Imperative Bowling Kata 20 Years On Delegating Menial Tasks to AI Coding Tool Claude Code A Very First Attempt Bowling Game Code Kata Claude Code Agentic code tool 🧑💻 @philip_schwarz slides by https://fpilluminated.org/ 

As can be seen on the next slide, in late 2000 Uncle Bob (Robert Martin) and Bob Koss pair programmed (in a hotel room) the Bowling Game, and (two years later) the ensuing programming episode was captured in glorious detail in the fourty or so pages constituting chapter six of the book Agile Software Development, Principles, Patterns, and Practices. The two Bobs were both associated members of Object Mentor, a now defunct company which was founded by Uncle Bob in 1991, and which advocated object-oriented software technologies and cutting-edge Agile development methodologies. In 1998, Object Mentor helped to define the Agile development method known as Extreme Programming. In 2000, Object Mentor helped form the Agile Alliance — a group of professionals dedicated to the advocacy of lean and emergent software methods. By 2005 Uncle Bob had practised the Bowling Game code kata hundreds of times (see slide after next for an overview of the term code kata), and although one of the key aspects of a code kata is that most times (if not each time) we ‘do’ a particular kata, we go through a unique learning experience, he decided to capture, in a deck called Bowling Game Kata, an example of the sequence of TDD steps that one may go through when performing the kata (see subsequent slides for where to find the original deck). The sequence illustrated in the deck is not meant to be ‘the’ ideal sequence, or a typical sequence. It is just a sequence whose length and particulars make it both amenable to capturing in a deck, and didactically suitable as a demonstration of ‘doing’ that kata. Here is what we are going to do in this deck (it will become perfectly obvious once we actually do it, so don’t worry if you find some or all of the following unclear): • Fire up coding tool Claude Code • Go through the original Bowling Game Kata deck, one slide at a time, and do the following for each original slide: • Show a copy of the original slide that has been modified as described in the next two bullet points • If relevant, highlight the code that is being added and/or modified in the TDD step illustrated by the original slide • Add a slide number • Add a slide showing: • how the code in the current original slide differs from the code in the previous original slide • a command that causes Claude to make code changes that result in the above differences • Add one or more slides showing an interaction in which we issue Claude with the command, and Claude obeys it, keeping us informed of actions taken, and their outcome. @philip_schwarz • Original slides are going to be marked with these two icons and a with page number • Highlighted code in original slides will look like this • Modified code in original slides will look like this • The Claude commands that we’ll be issuing will look like this run the test suite green 11 orange 

A Programming Episode Design and programming are human activities; forget that and all is lost. —Bjarne Stroustrup, 1991 In order to demonstrate the XP programming practices, Bob Koss (RSK) and Bob Martin (RCM) will pair program a simple application while you watch like a fly on the wall. We will use test-driven development and a lot of refactoring to create our application. What follows is a pretty faithful reenactment of a programming episode that the two Bobs did in a hotel room in late 2000. We made lots of mistakes while doing this. Some of the mistakes are in code, some are in logic, some are in design, and some are in requirements. As you read, you will see us flail around in all these areas, identifying and then dealing with our errors and misconceptions. The process is messy - as all human processes are. The result… well, it’s amazing the order that can arise out of such a messy process. The program calculates the score of a game of bowling, so it helps if you know the rules. If you don’t know the rules of bowling, check out the box on page 99 Image © Jennifer M. Kohnke 

No content

The next four slides provide a bit of context for the Bowling Game Kata deck, and show where the deck can be found. If you are already familiar with the deck, and already know where to find it, you might want to skip the slides, at least on a first reading. 

https://x.com/unclebobmartin http://cleancoder.com/products http://butunclebob.com/ … (continued) Robert C. Martin 

http://butunclebob.com/FrontPage … (continuing) 

http://butunclebob.com/ArticleS.UncleBob.TheProgrammingDojo 

http://butunclebob.com/ArticleS.UncleBob.TheBowlingGameKata http://butunclebob.com/files/downloads/Bowling%20Game%20Kata.ppt 

With that preamble out of the way, let’s start going through our lightly annotated copies of the slides of the Bowling Game Kata deck, and issuing relevant commands for Claude to obey. Be warned that there is nothing prescriptive or exemplary about the chosen commands. Just because the commands had the intended consequences, it doesn’t mean that they are of any particular merit. The commands are not the embodiment of any planned strategy and/or tactics aimed at securing a desired outcome in terms of e.g. optimality, effectiveness, efficiency, productivity. On the contrary, the commands are just whatever came to mind in a first and only session with Claude, the session’s proceedings being shown ’warts and all’. As a first example of this, while we begin by issuing commands purely consisting of prose, we later find it expedient to include in the commands some code fragments, small ones at first, and larger ones later on. As an other example, our prose commands are almost certainly more verbose than necessary given Claude’s ability to figure out the intent of commands. 

Bowling Game Kata Object Mentor, Inc. fitnesse.org Copyright © 2005 by Object Mentor, Inc All copies must retain this page unchanged. www.junit.org www.objectmentor.com blog.objectmentor.com 1 

Scoring Bowling. The game consists of 10 frames as shown above. In each frame the player has two opportunities to knock down 10 pins. The score for the frame is the total number of pins knocked down, plus bonuses for strikes and spares. A spare is when the player knocks down all 10 pins in two tries. The bonus for that frame is the number of pins knocked down by the next roll. So in frame 3 above, the score is 10 (the total number knocked down) plus a bonus of 5 (the number of pins knocked down on the next roll.) A strike is when the player knocks down all 10 pins on his first try. The bonus for that frame is the value of the next two balls rolled. In the tenth frame a player who rolls a spare or strike is allowed to roll the extra balls to complete the frame. However no more than three balls can be rolled in tenth frame. 2 

The Requirements. • Write a class named “Game” that has two methods – roll(pins : int) is called each time the player rolls a ball. The argument is the number of pins knocked down. – score() : int is called only at the very end of the game. It returns the total score for that game. 3 

A quick design session Clearly we need the Game class. 4 

A quick design session A game has 10 frames. 5 

A quick design session A frame has 1 or two rolls. 6 

A quick design session The tenth frame has two or three rolls. It is different from all the other frames. 7 

A quick design session The score function must iterate through all the frames, and calculate all their scores. 8 

A quick design session The score for a spare or a strike depends on the frame’s successor 9 

Begin. • Create a project named BowlingGame 10 

create an empty java project called claude-practice using the latest versions of java and junit as of 2005 9 10 

By the way: I have chosen project name claude-practice, rather than bowling-kata, just in case the latter would prompt Claude to search my laptop for existing related code and/or documents which might skew the results of this experiment. Similarly, in a later slide I choose class name Test, ather than BowlingGameTest. 

$ claude ╭─── Claude Code v2.0.75 ────────────────────────────────────────────────────────────────────────────────────────────────╮ │ │ Tips for getting started │ │ Welcome back Philip! │ Run /init to create a CLAUDE.md file with instructions for Claude │ │ │ ───────────────────────────────────────────────────────────────── │ │ * ▗ ▗ ▖ ▖ * │ Recent activity │ │ * * │ No recent activity │ │ * ▘▘ ▝▝ * │ │ │ │ │ │ Opus 4.5 · Claude Pro · │ │ │ [email protected]'s Organization │ │ │ ~/dev/claude-code-experiment │ │ ╰────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────╯ > create an empty java project called claude-practice using the latest versions of java and junit as of 2005 ⏺ Bash(mkdir -p claude-practice/src/main/java claude-practice/src/test/java claude-practice/lib) ⎿ Running… ──────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────── Bash command mkdir -p claude-practice/src/main/java claude-practice/src/test/java claude-practice/lib Create project directory structure Do you want to proceed? (Tab to add further instructions) ❯ 1. Yes 2. Yes, and don't ask again for mkdir commands in /Users/philipschwarz/dev/claude-code-experiment 3. No Esc to cancel 

⏺ As of 2005, the latest versions were Java 5 (JDK 1.5) and JUnit 3.8.1 (JUnit 4 didn't arrive until early 2006). Ant was the standard build tool at the time. ⏺ Write(claude-practice/build.xml) ─────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────── Create file claude-practice/build.xml ╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌ 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 31 32 33 34 35 39 40 41 42 43 44 45 46 47 48 49 50 ╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌ Do you want to create build.xml? (Tab to add further instructions) ❯ 1. Yes 2. Yes, allow all edits during this session (shift+tab) 3. No Esc to cancel 

⏺ Now let me download JUnit 3.8.1: ⏺ Bash(curl -sL -o /Users/philipschwarz/dev/claude-code-experiment/claude-practice/lib/junit-3.8.1.jar https://repo1.maven.org/maven2/junit/junit/3.8.1/junit-3.8.1.jar…) ⎿ Running… ────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────── Bash command curl -sL -o /Users/philipschwarz/dev/claude-code-experiment/claude-practice/lib/junit-3.8.1.jar https://repo1.maven.org/maven2/junit/junit/3.8.1/junit-3.8.1.jar && ls -la /Users/philipschwarz/dev/claude-code-experiment/claude-practice/lib/Download JUnit 3.8.1 jar Do you want to proceed? (Tab to add further instructions) ❯ 1. Yes 2. Yes, and don't ask again for curl commands in /Users/philipschwarz/dev/claude-code-experiment 3. No Esc to cancel ⏺ The claude-practice project is ready. Here's what was created: claude-practice/ ├── build.xml # Ant build file (Java 1.5 source/target) ├── lib/ │ └── junit-3.8.1.jar # JUnit 3.8.1 ├── src/ │ ├── main/java/ # Production source │ └── test/java/ # Test source Versions used (latest as of 2005): - Java 5 (JDK 1.5) — released Sept 2004 - JUnit 3.8.1 — released Nov 2003 (JUnit 4 wasn't released until Feb 2006) - Ant build file — the standard build tool of the era Build commands: ant compile, ant test, ant clean. ────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────── > now add a failing test 

Begin. • Create a project named BowlingGame • Create a unit test named BowlingGameTest import junit.framework.TestCase; public class BowlingGameTest extends TestCase { } 11 

create a unit test called Test 10 11 

> create a unit test called Test ⏺ Write(claude-practice/src/test/java/Test.java) ──────────────────────────────────────────────────────────────────────────────────── Create file claude-practice/src/test/java/Test.java ╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌ 1 import junit.framework.TestCase; 2 3 public class Test extends TestCase { 4 5 } ╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌ Do you want to create Test.java? (Tab to add further instructions) ❯ 1. Yes 2. Yes, allow all edits during this session (shift+tab) 3. No Esc to cancel > create a unit test called Test ⏺ Write(claude-practice/src/test/java/Test.java) ⎿ Wrote 6 lines to claude-practice/src/test/java/Test.java 1 import junit.framework.TestCase; 2 public class Test extends TestCase { 3 } ⏺ Created src/test/java/Test.java — an empty JUnit 3 test case extending TestCase. ──────────────────────────────────────────────────────────────────────────────────── > add a test method 

Begin. • Create a project named BowlingGame • Create a unit test named BowlingGameTest import junit.framework.TestCase; public class BowlingGameTest extends TestCase { } Excute this program and verify that you get the following error: No tests found in BowlingGameTest 12 

run the test suite 11 12 

> run the test suite ⏺ Bash(cd /Users/philipschwarz/dev/claude-code-experiment/claude-practice && ant test) ⎿ Error: Exit code 127 (eval):1: command not found: ant ⏺ Ant isn't installed. Let me check what's available: ⏺ Bash(which javac java 2>&1; java -version 2>&1) ⎿ Running… ─────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────── Bash command which javac java 2>&1; java -version 2>&1 Check Java availability Do you want to proceed? (Tab to add further instructions) ❯ 1. Yes 2. Yes, and don't ask again for java commands in /Users/philipschwarz/dev/claude-code-experiment 3. No Esc to cancel 

⏺ No Ant, but Java is available. I'll compile and run the tests directly: ⏺ Bash(cd /Users/philipschwarz/dev/claude-code-experiment/claude-practice && mkdir -p build/test-classes && javac -cp lib/junit-3.8.1.jar -d build/test-classes src/tes…) ⎿ Running… ─────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────── Bash command cd /Users/philipschwarz/dev/claude-code-experiment/claude-practice && mkdir -p build/test-classes && javac -cp lib/junit-3.8.1.jar -d build/test-classes src/test/java/Test.java && java -cp lib/junit-3.8.1.jar:build/test-classes junit.textui.TestRunner Test Compile and run JUnit tests Do you want to proceed? (Tab to add further instructions) ❯ 1. Yes 2. No Esc to cancel ⏺ Bash(cd /Users/philipschwarz/dev/claude-code-experiment/claude-practice && mkdir -p build/test-classes && javac -cp lib/junit-3.8.1.jar -d build/test-classes src/tes…) ⎿ Error: Exit code 1 .F Time: 0.002 There was 1 failure: 1) warning(junit.framework.TestSuite$1)junit.framework.AssertionFailedError: No tests found in Test FAILURES!!! Tests run: 1, Failures: 1, Errors: 0 ⏺ The test suite compiled and ran successfully. JUnit 3 reports a warning because the Test class has no test methods yet — that's expected for an empty test case. ─────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────── > add a test method 

The first test. import junit.framework.TestCase; public class BowlingGameTest extends TestCase { public void testGutterGame() throws Exception { Game g = new Game(); } } 13 

Add to the test suite a test called testGutterGame which simply defines variable g and sets it to an instance of a non-existent class called Game 12 13 

> Add to the test suite a test called testGutterGame which simply defines variable g and sets it to an instance of a non-existent class called Game ⏺ Read(claude-practice/src/test/java/Test.java) ⎿ Read 6 lines ⏺ Update(claude-practice/src/test/java/Test.java) ─────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────── Edit file claude-practice/src/test/java/Test.java ╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌ 2 3 public class Test extends TestCase { 4 5 + public void testGutterGame() { 6 + Game g = new Game(); 7 + } 8 } ╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌ Do you want to make this edit to Test.java? (Tab to add further instructions) ❯ 1. Yes 2. Yes, allow all edits during this session (shift+tab) 3. No Esc to cancel ⏺ Added testGutterGame. It references the non-existent Game class, so it won't compile until that class is created. ─────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────── > create the Game class so the test compiles ↵ send ─────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────── 

The first test. import junit.framework.TestCase; public class BowlingGameTest extends TestCase { public void testGutterGame() throws Exception { Game g = new Game(); } } public class Game { } 14 

create the Game class so the test compiles 13 14 

> create the Game class so the test compiles ⏺ Write(claude-practice/src/main/java/Game.java) ─────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────── Create file claude-practice/src/main/java/Game.java ╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌ 1 public class Game { 2 3 } ╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌ Do you want to create Game.java? (Tab to add further instructions) ❯ 1. Yes 2. Yes, allow all edits during this session (shift+tab) 3. No Esc to cancel ⏺ Write(claude-practice/src/main/java/Game.java) ⎿ Wrote 4 lines to claude-practice/src/main/java/Game.java 1 public class Game { 2 } ⏺ Created src/main/java/Game.java. The test should now compile. ─────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────── > run the tests 

The first test. import junit.framework.TestCase; public class BowlingGameTest extends TestCase { public void testGutterGame() throws Exception { Game g = new Game(); } } public class Game { } 15 

run the tests 14 15 

> run the tests ⏺ Bash(cd /Users/philipschwarz/dev/claude-code-experiment/claude-practice && mkdir -p build/classes build/test-classes && javac -d build/classes src/main/java/Game.jav…) ⎿ Running… ─────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────── Bash command cd /Users/philipschwarz/dev/claude-code-experiment/claude-practice && mkdir -p build/classes build/test-classes && javac -d build/classes src/main/java/Game.java && javac -cp lib/junit-3.8.1.jar:build/classes -d build/test-classes src/test/java/Test.java && java -cp lib/junit-3.8.1.jar:build/classes:build/test-classes junit.textui.TestRunner Test Compile and run JUnit tests Do you want to proceed? (Tab to add further instructions) ❯ 1. Yes 2. No Esc to cancel > run the tests ⏺ Bash(cd /Users/philipschwarz/dev/claude-code-experiment/claude-practice && mkdir -p build/classes build/test-classes && javac -d build/classes src/main/java/Game.jav…) ⎿ . Time: 0.001 OK (1 test) ⏺ 1 test ran, all passing. ─────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────── > 

The first test. import junit.framework.TestCase; public class BowlingGameTest extends TestCase { public void testGutterGame() throws Exception { Game g = new Game(); for (int i=0; i<20; i++) g.roll(0); } } public class Game { } 16 

Modify testGutterGame so that, after defining g, it invokes twenty times, with an argument of zero, its non-existent method whose name is roll and whose single parameter is an integer number 15 16 

> Modify testGutterGame so that, after defining g, it invokes twenty times, with an argument of zero, its non-existent method whose name is roll and whose single parameter is an integer number ⏺ Update(src/test/java/Test.java) ─────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────── Edit file src/test/java/Test.java ╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌ 4 5 public void testGutterGame() { 6 Game g = new Game(); 7 + for (int i = 0; i < 20; i++) { 8 + g.roll(0); 9 + } 10 } 11 } ╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌ Do you want to make this edit to Test.java? (Tab to add further instructions) ❯ 1. Yes 2. Yes, allow all edits during this session (shift+tab) 3. No Esc to cancel ⏺ Added the loop calling g.roll(0) twenty times. This won't compile until Game has a roll(int) method. ─────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────── > create the roll method so the test compiles 

The first test. import junit.framework.TestCase; public class BowlingGameTest extends TestCase { public void testGutterGame() throws Exception { Game g = new Game(); for (int i=0; i<20; i++) g.roll(0); } } public class Game { public void roll(int pins) { } } 17 

Add to Game a method whose name is roll, and whose parameter is an integer called pins, and whose return type is void, and whose body is empty 15 16 

> Add to Game a method whose name is roll, and whose parameter is an integer called pins, and whose return type is void, and whose body is empty ⏺ Update(src/main/java/Game.java) ─────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────── Edit file src/main/java/Game.java ╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌ 1 public class Game { 2 3 + public void roll(int pins) { 4 + } 5 } ╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌ Do you want to make this edit to Game.java? (Tab to add further instructions) ❯ 1. Yes 2. Yes, allow all edits during this session (shift+tab) 3. No Esc to cancel ⏺ Added the roll(int pins) method to Game. ─────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────── > run the tests 

The first test. import junit.framework.TestCase; public class BowlingGameTest extends TestCase { public void testGutterGame() throws Exception { Game g = new Game(); for (int i=0; i<20; i++) g.roll(0); assertEquals(0, g.score()); } } public class Game { public void roll(int pins) { } } 18 

Modify testGutterGame so that after calling roll twenty times, it asserts that the result of invoking g's non-existent method called score is zero 17 18 

> Modify testGutterGame so that after calling roll twenty times, it asserts that the result of invoking g's non-existent method called score is zero ⏺ Update(src/test/java/Test.java) ─────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────── Edit file src/test/java/Test.java ╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌ 7 for (int i = 0; i < 20; i++) { 8 g.roll(0); 9 } 10 + assertEquals(0, g.score()); 11 } 12 } ╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌ Do you want to make this edit to Test.java? (Tab to add further instructions) ❯ 1. Yes 2. Yes, allow all edits during this session (shift+tab) 3. No ⏺ Added the assertion. This won't compile until Game has a score() method. ─────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────── > 

The first test. import junit.framework.TestCase; public class BowlingGameTest extends TestCase { public void testGutterGame() throws Exception { Game g = new Game(); for (int i=0; i<20; i++) g.roll(0); assertEquals(0, g.score()); } } public class Game { public void roll(int pins) { } public int score() { return -1; } } expected:<0> but was:<-1> 19 

Add to Game a zero-argument method whose name is score, and whose return type is integer, and whose body simply returns -1 run the tests 18 19 

> Add to Game a zero-argument method whose name is score, and whose return type is integer, and whose body simply returns -1 ⏺ Update(src/main/java/Game.java) ─────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────── Edit file src/main/java/Game.java ╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌ 2 3 public void roll(int pins) { 4 } 5 + 6 + public int score() { 7 + return -1; 8 + } 9 } ╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌ Do you want to make this edit to Game.java? (Tab to add further instructions) ❯ 1. Yes 2. Yes, allow all edits during this session (shift+tab) 3. No ⏺ Added the score() method returning -1. ─────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────── > run the tests 

> run the tests ⏺ Bash(mkdir -p build/classes build/test-classes && javac -d build/classes src/main/java/Game.java && javac -cp lib/junit-3.8.1.jar:build/classes -d build/test-classes…) ⎿ Running… ─────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────── Bash command mkdir -p build/classes build/test-classes && javac -d build/classes src/main/java/Game.java && javac -cp lib/junit-3.8.1.jar:build/classes -d build/test-classes src/test/java/Test.java && java -cp lib/junit-3.8.1.jar:build/classes:build/test-classes junit.textui.TestRunner Test Compile and run JUnit tests Do you want to proceed? (Tab to add further instructions) ❯ 1. Yes 2. Yes, and don't ask again for mkdir, javac, and java commands in /Users/philipschwarz/dev/claude-code-experiment 3. No Esc to cancel > run the tests ⏺ Bash(mkdir -p build/classes build/test-classes && javac -d build/classes src/main/java/Game.java && javac -cp lib/junit-3.8.1.jar:build/classes -d build/test-classes…) ⎿ Error: Exit code 1 .F Time: 0.002 There was 1 failure: 1) testGutterGame(Test)junit.framework.AssertionFailedError: expected:<0> but was:<-1> at Test.testGutterGame(Test.java:10) at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) … +2 lines (ctrl+o to see all) ⏺ The test fails as expected — score() returns -1 but the test expects 0. ─────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────── > Make score return 0 

The first test. import junit.framework.TestCase; public class BowlingGameTest extends TestCase { public void testGutterGame() throws Exception { Game g = new Game(); for (int i=0; i<20; i++) g.roll(0); assertEquals(0, g.score()); } } public class Game { public void roll(int pins) { } public int score() { return 0; } } 20 

19 20 Modify the body of the score method so that it returns zero rather than -1 run the tests 

> Modify the body of the score method so that it returns zero rather than -1 ⏺ Update(src/main/java/Game.java) ─────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────── Edit file src/main/java/Game.java ╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌ 4 } 5 6 public int score() { 7 - return -1; 7 + return 0; 8 } 9 } ╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌ Do you want to make this edit to Game.java? (Tab to add further instructions) ❯ 1. Yes 2. Yes, allow all edits during this session (shift+tab) 3. No Esc to cancel ⏺ Done — score() now returns 0. ─────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────── > run the tests 

> run the tests ⏺ Bash(mkdir -p build/classes build/test-classes && javac -d build/classes src/main/java/Game.java && javac -cp lib/junit-3.8.1.jar:build/classes -d build/test-classes…) ⎿ Running… ─────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────── Bash command mkdir -p build/classes build/test-classes && javac -d build/classes src/main/java/Game.java && javac -cp lib/junit-3.8.1.jar:build/classes -d build/test-classes src/test/java/Test.java && java -cp lib/junit-3.8.1.jar:build/classes:build/test-classes junit.textui.TestRunner Test Compile and run JUnit tests Do you want to proceed? (Tab to add further instructions) ❯ 1. Yes 2. Yes, and don't ask again for mkdir, javac, and java commands in /Users/philipschwarz/dev/claude-code-experiment 3. No Esc to cancel > run the tests ⏺ Bash(mkdir -p build/classes build/test-classes && javac -d build/classes src/main/java/Game.java && javac -cp lib/junit-3.8.1.jar:build/classes -d build/test-classes…) ⎿ . Time: 0.002 OK (1 test) ⏺ 1 test ran, all passing. ─────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────── > add a second test called testAllOnes 

The Second test. import junit.framework.TestCase; public class BowlingGameTest extends TestCase { public void testGutterGame() throws Exception { Game g = new Game(); for (int i = 0; i < 20; i++) g.roll(0); assertEquals(0, g.score()); } public void testAllOnes() throws Exception { Game g = new Game(); for (int i = 0; i < 20; i++) g.roll(1); assertEquals(20, g.score()); } } public class Game { public void roll(int pins) { } public int score() { return 0; } } 21 

20 21 Add a new test that is called testAllOnes, and ony differs from testGutterGame in that it invokes roll with one rather than with zero, and it asserts that the result of invoking score is twenty rather than zero 

> Add a new test that is called testAllOnes, and ony differs from testGutterGame in that it invokes roll with one rather than with zero, and it asserts that the result of invoking score is twenty rather than zero ⏺ Read(src/test/java/Test.java) ⎿ Read 13 lines ⏺ Update(src/test/java/Test.java) ─────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────── Edit file src/test/java/Test.java ╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌ 9 } 10 assertEquals(0, g.score()); 11 } 12 + 13 + public void testAllOnes() { 14 + Game g = new Game(); 15 + for (int i = 0; i < 20; i++) { 16 + g.roll(1); 17 + } 18 + assertEquals(20, g.score()); 19 + } 20 } ╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌ Do you want to make this edit to Test.java? (Tab to add further instructions) ❯ 1. Yes 2. Yes, allow all edits during this session (shift+tab) 3. No Esc to cancel ⏺ Added testAllOnes. ─────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────── > run the tests 

The Second test. import junit.framework.TestCase; public class BowlingGameTest extends TestCase { public void testGutterGame() throws Exception { Game g = new Game(); for (int i = 0; i < 20; i++) g.roll(0); assertEquals(0, g.score()); } public void testAllOnes() throws Exception { Game g = new Game(); for (int i = 0; i < 20; i++) g.roll(1); assertEquals(20, g.score()); } } public class Game { public void roll(int pins) { } public int score() { return 0; } } - Game creation is duplicated - roll loop is duplicated 22 

The Second test. import junit.framework.TestCase; public class BowlingGameTest extends TestCase { public void testGutterGame() throws Exception { Game g = new Game(); for (int i = 0; i < 20; i++) g.roll(0); assertEquals(0, g.score()); } public void testAllOnes() throws Exception { Game g = new Game(); for (int i = 0; i < 20; i++) g.roll(1); assertEquals(20, g.score()); } } public class Game { public void roll(int pins) { } public int score() { return 0; } } - Game creation is duplicated - roll loop is duplicated expected:<20> but was:<0> 23 

run the tests 22 23 

> run the tests ⏺ Bash(mkdir -p build/classes build/test-classes && javac -d build/classes src/main/java/Game.java && javac -cp lib/junit-3.8.1.jar:build/classes -d build/test-classes…) ⎿ Error: Exit code 1 .F. Time: 0.002 There was 1 failure: 1) testAllOnes(Test)junit.framework.AssertionFailedError: expected:<20> but was:<0> at Test.testAllOnes(Test.java:18) at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) … +2 lines (ctrl+o to see all) ⏺ testGutterGame passes but testAllOnes fails — score() still returns a hardcoded 0 instead of summing the rolls. ─────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────── > 

The Second test. import junit.framework.TestCase; public class BowlingGameTest extends TestCase { private Game g; protected void setUp() throws Exception { g = new Game(); } public void testGutterGame() throws Exception { for (int i = 0; i < 20; i++) g.roll(0); assertEquals(0, g.score()); } public void testAllOnes() throws Exception { for (int i = 0; i < 20; i++) g.roll(1); assertEquals(20, g.score()); } } public class Game { private int score = 0; public void roll(int pins) { score += pins; } public int score() { return score; } } - roll loop is duplicated 24 

refactor g so that it is a private variable of Game that is initialised with a Game instance before the execution of each test Add to Game an integer variable named score and initialised to zero Modify roll so that rather than doing nothing it increments variable score by the value of its pins argument Modify score method so that rather than always returning zero it returns variable score run the tests 23 24 

> refactor g so that it is a private variable of Game that is initialised with a Game instance before the execution of each test ⏺ Read(src/test/java/Test.java) ⎿ Read 21 lines ⏺ Write(src/test/java/Test.java) ─────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────── Overwrite file src/test/java/Test.java ╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌ 2 3 public class Test extends TestCase { 4 5 + private Game g; 6 + 7 + protected void setUp() throws Exception { 8 + super.setUp(); 9 + g = new Game(); 10 + } 11 + 12 public void testGutterGame() { 6 - Game g = new Game(); 13 for (int i = 0; i < 20; i++) { 14 g.roll(0); 15 } ... 17 } 18 19 public void testAllOnes() { 14 - Game g = new Game(); 20 for (int i = 0; i < 20; i++) { 21 g.roll(1); 22 } ╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌ Do you want to overwrite Test.java? (Tab to add further instructions) ❯ 1. Yes 2. Yes, allow all edits during this session (shift+tab) 3. No Esc to cancel ⏺ Refactored g to a private field, initialized in setUp() before each test. ─────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────── > run the tests 

> Add to Game an integer variable named score and initialised to zero ⏺ Read(src/main/java/Game.java) ⎿ Read 10 lines ⏺ Update(src/main/java/Game.java) ─────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────── Edit file src/main/java/Game.java ╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌ 1 public class Game { 2 3 + private int score = 0; 4 + 5 public void roll(int pins) { 6 } 7 ╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌ Do you want to make this edit to Game.java? (Tab to add further instructions) ❯ 1. Yes 2. Yes, allow all edits during this session (shift+tab) 3. No Esc to cancel ⏺ Added private int score = 0; to Game. ─────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────── > 

> Modify roll so that rather than doing nothing it increments variable score by the value of its pins argument ⏺ Update(src/main/java/Game.java) ─────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────── Edit file src/main/java/Game.java ╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌ 3 private int score = 0; 4 5 public void roll(int pins) { 6 + score += pins; 7 } 8 9 public int score() { ╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌ Do you want to make this edit to Game.java? (Tab to add further instructions) ❯ 1. Yes 2. Yes, allow all edits during this session (shift+tab) 3. No Esc to cancel ⏺ Done — roll now adds pins to score. ─────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────── > 

> Modify score method so that rather than always returning zero it returns variable score ⏺ Update(src/main/java/Game.java) ─────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────── Edit file src/main/java/Game.java ╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌ 7 } 8 9 public int score() { 10 - return 0; 10 + return score; 11 } 12 } ╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌ Do you want to make this edit to Game.java? (Tab to add further instructions) ❯ 1. Yes 2. Yes, allow all edits during this session (shift+tab) 3. No Esc to cancel ⏺ Done — score() now returns the score variable. ─────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────── > run the tests > run the tests ⏺ Bash(mkdir -p build/classes build/test-classes && javac -d build/classes src/main/java/Game.java && javac -cp lib/junit-3.8.1.jar:build/classes -d build/test-classes…) ⎿ .. Time: 0.001 OK (2 tests) ⏺ 2 tests ran, all passing. ─────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────── > add a test for a spare 

The Second test. import junit.framework.TestCase; public class BowlingGameTest extends TestCase { private Game g; protected void setUp() throws Exception { g = new Game(); } public void testGutterGame() throws Exception { int n = 20; int pins = 0; for (int i = 0; i < n; i++) { g.roll(pins); } assertEquals(0, g.score()); } public void testAllOnes() throws Exception { for (int i = 0; i < 20; i++) g.roll(1); assertEquals(20, g.score()); } } public class Game { private int score = 0; public void roll(int pins) { score += pins; } public int score() { return score; } } - roll loop is duplicated 25 

24 25 Refactor the line in testGutterGame that invokes the roll method: extract 20, the max value of the range, into integer val n, and extract 0, the parameter passed to roll, into integer val pins run the tests 

> Refactor the line in testGutterGame that invokes the roll method: extract 20, the max value of the range, into integer val n, and extract 0, the parameter passed to roll, into integer val pins ⏺ Update(src/test/java/Test.java) ───────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────── Edit file src/test/java/Test.java ╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌ 10 } 11 12 public void testGutterGame() { 13 - for (int i = 0; i < 20; i++) { 14 - g.roll(0); 13 + int n = 20; 14 + int pins = 0; 15 + for (int i = 0; i < n; i++) { 16 + g.roll(pins); 17 } 18 assertEquals(0, g.score()); 19 } ╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌ Do you want to make this edit to Test.java? (Tab to add further instructions) ❯ 1. Yes 2. Yes, allow all edits during this session (shift+tab) 3. No Esc to cancel ⏺ Extracted n = 20 and pins = 0 in testGutterGame. ───────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────── > > run the tests ⏺ Bash(mkdir -p build/classes build/test-classes && javac -d build/classes src/main/java/Game.java && javac -cp lib/junit-3.8.1.jar:build/classes -d build/test-classes…) ⎿ .. Time: 0.001 OK (2 tests) ⏺ 2 tests ran, all passing. ──────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────── > 

The Second test. import junit.framework.TestCase; public class BowlingGameTest extends TestCase { private Game g; protected void setUp() throws Exception { g = new Game(); } public void testGutterGame() throws Exception { int n = 20; int pins = 0; rollMany(n, pins); assertEquals(0, g.score()); } private void rollMany(int n, int pins) { for (int i = 0; i < n; i++) g.roll(pins); } public void testAllOnes() throws Exception { for (int i = 0; i < 20; i++) g.roll(1); assertEquals(20, g.score()); } } public class Game { private int score = 0; public void roll(int pins) { score += pins; } public int score() { return score; } } - roll loop is duplicated 26 

The Second test. import junit.framework.TestCase; public class BowlingGameTest extends TestCase { private Game g; protected void setUp() throws Exception { g = new Game(); } public void testGutterGame() throws Exception { rollMany(20, 0); assertEquals(0, g.score()); } private void rollMany(int n, int pins) { for (int i = 0; i < n; i++) g.roll(pins); } public void testAllOnes() throws Exception { for (int i = 0; i < 20; i++) g.roll(1); assertEquals(20, g.score()); } } public class Game { private int score = 0; public void roll(int pins) { score += pins; } public int score() { return score; } } - roll loop is duplicated 27 

Extract into method rollMany the loop that invokes method roll in testGutterGame run the tests 26 27 25 26 

> Extract into method rollMany the loop that invokes method roll in testGutterGame ⏺ Update(src/test/java/Test.java) ───────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────── Edit file src/test/java/Test.java ╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌ 9 g = new Game(); 10 } 11 12 - public void testGutterGame() { 13 - int n = 20; 14 - int pins = 0; 12 + private void rollMany(int n, int pins) { 13 for (int i = 0; i < n; i++) { 14 g.roll(pins); 15 } 16 + } 17 + 18 + public void testGutterGame() { 19 + rollMany(20, 0); 20 assertEquals(0, g.score()); 21 } 22 ╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌ Do you want to make this edit to Test.java? (Tab to add further instructions) ❯ 1. Yes 2. Yes, allow all edits during this session (shift+tab) 3. No Esc to cancel ⏺ Extracted rollMany from testGutterGame. The loop in testAllOnes is unchanged. ───────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────── > now use rollMany in testAllOnes too 

The Second test. import junit.framework.TestCase; public class BowlingGameTest extends TestCase { private Game g; protected void setUp() throws Exception { g = new Game(); } public void testGutterGame() throws Exception { rollMany(20, 0); assertEquals(0, g.score()); } private void rollMany(int n, int pins) { for (int i = 0; i < n; i++) g.roll(pins); } public void testAllOnes() throws Exception { rollMany(20,1); assertEquals(20, g.score()); } } public class Game { private int score = 0; public void roll(int pins) { score += pins; } public int score() { return score; } } - roll loop is duplicated 28 

The Second test. import junit.framework.TestCase; public class BowlingGameTest extends TestCase { private Game g; protected void setUp() throws Exception { g = new Game(); } private void rollMany(int n, int pins) { for (int i = 0; i < n; i++) g.roll(pins); } public void testGutterGame() throws Exception { rollMany(20, 0); assertEquals(0, g.score()); } public void testAllOnes() throws Exception { rollMany(20,1); assertEquals(20, g.score()); } } public class Game { private int score = 0; public void roll(int pins) { score += pins; } public int score() { return score; } } 29 

28 29 27 28 now use rollMany in testAllOnes too run the tests 

> now use rollMany in testAllOnes too ⏺ Update(src/test/java/Test.java) ───────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────── Edit file src/test/java/Test.java ╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌ 21 } 22 23 public void testAllOnes() { 24 - for (int i = 0; i < 20; i++) { 25 - g.roll(1); 26 - } 24 + rollMany(20, 1); 25 assertEquals(20, g.score()); 26 } 27 } ╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌ Do you want to make this edit to Test.java? (Tab to add further instructions) ❯ 1. Yes 2. Yes, allow all edits during this session (shift+tab) 3. No Esc to cancel ⏺ Done — testAllOnes now uses rollMany(20, 1). ───────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────── > run the tests > run the tests ⏺ Bash(mkdir -p build/classes build/test-classes && javac -d build/classes src/main/java/Game.java && javac -cp lib/junit-3.8.1.jar:build/classes -d build/test-classes…) ⎿ .. Time: 0.001 OK (2 tests) ⏺ 2 tests ran, all passing. ──────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────── > 

The Third test. import junit.framework.TestCase; public class BowlingGameTest extends TestCase { private Game g; protected void setUp() throws Exception { g = new Game(); } private void rollMany(int n, int pins) { for (int i = 0; i < n; i++) g.roll(pins); } public void testGutterGame() throws Exception { rollMany(20, 0); assertEquals(0, g.score()); } public void testAllOnes() throws Exception { rollMany(20,1); assertEquals(20, g.score()); } public void testOneSpare() throws Exception { g.roll(5); g.roll(5); // spare g.roll(3); rollMany(17,0); assertEquals(16,g.score()); } } public class Game { private int score = 0; public void roll(int pins) { score += pins; } public int score() { return score; } } - ugly comment in test. 30 

29 30 Write new test testOneSpare which (1) invokes roll twice with pins=5, and once with pins=3 (2) invokes rollMany with n=17 and pins=0 (3) asserts that the result of invoking score is 16 Append comment "// spare" to the second line in testOneSpare that invokes roll with pins=5 

> Write new test testOneSpare which (1) invokes roll twice with pins=5, and once with pins= 3 (2) invokes rollMany with n=17 and pins=0 (3) asserts that the result of invoking score is 16 ⏺ Update(src/test/java/Test.java) ───────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────── Edit file src/test/java/Test.java ╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌ 20 assertEquals(0, g.score()); 21 } 22 23 + public void testOneSpare() { 24 + g.roll(5); 25 + g.roll(5); 26 + g.roll(3); 27 + rollMany(17, 0); 28 + assertEquals(16, g.score()); 29 + } 30 + 31 public void testAllOnes() { 32 rollMany(20, 1); 33 assertEquals(20, g.score()); ╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌ Do you want to make this edit to Test.java? (Tab to add further instructions) ❯ 1. Yes 2. Yes, allow all edits during this session (shift+tab) 3. No Esc to cancel ⏺ Added testOneSpare. ───────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────── > run the tests 

> Append comment "// spare" to the second line in testOneSpare that invokes roll with pins=5 ⏺ Update(src/test/java/Test.java) ───────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────── Edit file src/test/java/Test.java ╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌ 22 23 public void testOneSpare() { 24 g.roll(5); 25 - g.roll(5); 25 + g.roll(5); // spare 26 g.roll(3); 27 rollMany(17, 0); 28 assertEquals(16, g.score()); ╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌ Do you want to make this edit to Test.java? (Tab to add further instructions) ❯ 1. Yes 2. Yes, allow all edits during this session (shift+tab) 3. No Esc to cancel ⏺ Done. ───────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────── > 

The Third test. import junit.framework.TestCase; public class BowlingGameTest extends TestCase { private Game g; protected void setUp() throws Exception { g = new Game(); } private void rollMany(int n, int pins) { for (int i = 0; i < n; i++) g.roll(pins); } public void testGutterGame() throws Exception { rollMany(20, 0); assertEquals(0, g.score()); } public void testAllOnes() throws Exception { rollMany(20,1); assertEquals(20, g.score()); } public void testOneSpare() throws Exception { g.roll(5); g.roll(5); // spare g.roll(3); rollMany(17,0); assertEquals(16,g.score()); } } public class Game { private int score = 0; public void roll(int pins) { score += pins; } public int score() { return score; } } - ugly comment in test. expected:<16> but was:<13> 31 

run the tests 30 31 

> run the tests ⏺ Bash(mkdir -p build/classes build/test-classes && javac -d build/classes src/main/java/Game.java && javac -cp lib/junit-3.8.1.jar:build/classes -d build/test-classes…) ⎿ Error: Exit code 1 ..F. Time: 0.002 There was 1 failure: 1) testOneSpare(Test)junit.framework.AssertionFailedError: expected:<16> but was:<13> at Test.testOneSpare(Test.java:28) at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) … +2 lines (ctrl+o to see all) ⏺ testOneSpare fails — expected 16 but got 13. The spare bonus (adding the next roll's pins) isn't implemented yet. The other 2 tests pass. ───────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────── > 

The Third test. import junit.framework.TestCase; public class BowlingGameTest extends TestCase { private Game g; protected void setUp() throws Exception { g = new Game(); } private void rollMany(int n, int pins) { for (int i = 0; i < n; i++) g.roll(pins); } public void testGutterGame() throws Exception { rollMany(20, 0); assertEquals(0, g.score()); } public void testAllOnes() throws Exception { rollMany(20,1); assertEquals(20, g.score()); } public void testOneSpare() throws Exception { g.roll(5); g.roll(5); // spare g.roll(3); rollMany(17,0); assertEquals(16,g.score()); } } public class Game { private int score = 0; public void roll(int pins) { score += pins; } public int score() { return score; } } - ugly comment in test. tempted to use flag to remember previous roll. So design must be wrong. 32 

The Third test. import junit.framework.TestCase; public class BowlingGameTest extends TestCase { private Game g; protected void setUp() throws Exception { g = new Game(); } private void rollMany(int n, int pins) { for (int i = 0; i < n; i++) g.roll(pins); } public void testGutterGame() throws Exception { rollMany(20, 0); assertEquals(0, g.score()); } public void testAllOnes() throws Exception { rollMany(20,1); assertEquals(20, g.score()); } public void testOneSpare() throws Exception { g.roll(5); g.roll(5); // spare g.roll(3); rollMany(17,0); assertEquals(16,g.score()); } } public class Game { private int score = 0; public void roll(int pins) { score += pins; } public int score() { return score; } } - ugly comment in test. roll() calculates score, but name does not imply that. score() does not calculate score, but name implies that it does. Design is wrong. Responsibilities are misplaced. 33 

The Third test. import junit.framework.TestCase; public class BowlingGameTest extends TestCase { private Game g; protected void setUp() throws Exception { g = new Game(); } private void rollMany(int n, int pins) { for (int i = 0; i < n; i++) g.roll(pins); } public void testGutterGame() throws Exception { rollMany(20, 0); assertEquals(0, g.score()); } public void testAllOnes() throws Exception { rollMany(20,1); assertEquals(20, g.score()); } // public void testOneSpare() throws Exception { // g.roll(5); // g.roll(5); // spare // g.roll(3); // rollMany(17,0); // assertEquals(16,g.score()); // } } public class Game { private int score = 0; public void roll(int pins) { score += pins; } public int score() { return score; } } - ugly comment in test. 34 

31 34 comment out testOneSpare run the tests 

> comment out testOneSpare ⏺ Update(src/test/java/Test.java) ───────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────── Edit file src/test/java/Test.java ╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌ 20 assertEquals(0, g.score()); 21 } 22 23 - public void testOneSpare() { 24 - g.roll(5); 25 - g.roll(5); // spare 26 - g.roll(3); 27 - rollMany(17, 0); 28 - assertEquals(16, g.score()); 29 - } 23 + // public void testOneSpare() { 24 + // g.roll(5); 25 + // g.roll(5); // spare 26 + // g.roll(3); 27 + // rollMany(17, 0); 28 + // assertEquals(16, g.score()); 29 + // } 30 31 public void testAllOnes() { 32 rollMany(20, 1); ╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌ Do you want to make this edit to Test.java? (Tab to add further instructions) ❯ 1. Yes 2. Yes, allow all edits during this session (shift+tab) 3. No Esc to cancel ⏺ Done — testOneSpare is commented out. ───────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────── > show the current state of Game 

> run the tests ⏺ Bash(mkdir -p build/classes build/test-classes && javac -d build/classes src/main/java/Game.java && javac -cp lib/junit-3.8.1.jar:build/classes -d build/test-classes…) ⎿ .. Time: 0.001 OK (2 tests) ⏺ 2 tests ran, all passing. ──────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────── > 

The Third test. import junit.framework.TestCase; public class BowlingGameTest extends TestCase { private Game g; protected void setUp() throws Exception { g = new Game(); } private void rollMany(int n, int pins) { for (int i = 0; i < n; i++) g.roll(pins); } public void testGutterGame() throws Exception { rollMany(20, 0); assertEquals(0, g.score()); } public void testAllOnes() throws Exception { rollMany(20,1); assertEquals(20, g.score()); } // public void testOneSpare() throws Exception { // g.roll(5); // g.roll(5); // spare // g.roll(3); // rollMany(17,0); // assertEquals(16,g.score()); // } } public class Game { private int score = 0; private int rolls[] = new int[21]; private int currentRoll = 0; public void roll(int pins) { score += pins; rolls[currentRoll++] = pins; } public int score() { return score; } } - ugly comment in test. 35 

Add to Game (1) integer array variable rolls initialized with an array of 21 zeroes (2) integer variable currentRoll initialized with zero run the tests Add to roll a second line that sets rolls element at index currentRoll to pins and increments currentRoll by 1 34 35 

> Add to Game (1) integer array variable rolls initialized with an array of 21 zeroes (2) integer variable currentRoll initialized with zero ⏺ Update(src/main/java/Game.java) ───────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────── Edit file src/main/java/Game.java ╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌ 1 public class Game { 2 3 private int score = 0; 4 + private int[] rolls = new int[21]; 5 + private int currentRoll = 0; 6 7 public void roll(int pins) { 8 score += pins; ╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌ Do you want to make this edit to Game.java? (Tab to add further instructions) ❯ 1. Yes 2. Yes, allow all edits during this session (shift+tab) 3. No Esc to cancel ⏺ Done — added rolls (array of 21 zeroes) and currentRoll (initialized to 0). ───────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────── > 

> Add to roll a second line that sets rolls element at index currentRoll to pins and increments currentRoll by 1 ⏺ Update(src/main/java/Game.java) ───────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────── Edit file src/main/java/Game.java ╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌ 6 7 public void roll(int pins) { 8 score += pins; 9 + rolls[currentRoll++] = pins; 10 } 11 12 public int score() { ╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌ Do you want to make this edit to Game.java? (Tab to add further instructions) ❯ 1. Yes 2. Yes, allow all edits during this session (shift+tab) 3. No Esc to cancel ⏺ Done — added rolls[currentRoll++] = pins; to roll. ───────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────── > run the tests > run the tests ⏺ Bash(mkdir -p build/classes build/test-classes && javac -d build/classes src/main/java/Game.java && javac -cp lib/junit-3.8.1.jar:build/classes -d build/test-classes…) ⎿ .. Time: 0.002 OK (2 tests) ⏺ 2 tests ran, all passing. ───────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────── > 

The Third test. import junit.framework.TestCase; public class BowlingGameTest extends TestCase { private Game g; protected void setUp() throws Exception { g = new Game(); } private void rollMany(int n, int pins) { for (int i = 0; i < n; i++) g.roll(pins); } public void testGutterGame() throws Exception { rollMany(20, 0); assertEquals(0, g.score()); } public void testAllOnes() throws Exception { rollMany(20,1); assertEquals(20, g.score()); } // public void testOneSpare() throws Exception { // g.roll(5); // g.roll(5); // spare // g.roll(3); // rollMany(17,0); // assertEquals(16,g.score()); // } } public class Game { private int score = 0; private int rolls[] = new int[21]; private int currentRoll = 0; public void roll(int pins) { score += pins; rolls[currentRoll++] = pins; } public int score() { int score = 0; for (int i = 0; i < rolls.length; i++) score += rolls[i]; return score; } } - ugly comment in test. 36 

run the tests Modify score method so that (1) it defines integer variable score initialised to zero (2) loops through rolls elements adding them to score 35 36 

> Modify score method so that (1) it defines integer variable score initialised to zero (2) loops through rolls elements adding them to score ⏺ Update(src/main/java/Game.java) ───────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────── Edit file src/main/java/Game.java ╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌ 10 } 11 12 public int score() { 13 + int score = 0; 14 + for (int i = 0; i < rolls.length; i++) { 15 + score += rolls[i]; 16 + } 17 return score; 18 } 19 } ╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌ Do you want to make this edit to Game.java? (Tab to add further instructions) ❯ 1. Yes 2. Yes, allow all edits during this session (shift+tab) 3. No Esc to cancel ⏺ Done — score() now sums the rolls array using a local score variable. ───────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────── > run the tests > run the tests ⏺ Bash(mkdir -p build/classes build/test-classes && javac -d build/classes src/main/java/Game.java && javac -cp lib/junit-3.8.1.jar:build/classes -d build/test-classes…) ⎿ .. Time: 0.002 OK (2 tests) ⏺ 2 tests ran, all passing. ───────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────── > 

The Third test. import junit.framework.TestCase; public class BowlingGameTest extends TestCase { private Game g; protected void setUp() throws Exception { g = new Game(); } private void rollMany(int n, int pins) { for (int i = 0; i < n; i++) g.roll(pins); } public void testGutterGame() throws Exception { rollMany(20, 0); assertEquals(0, g.score()); } public void testAllOnes() throws Exception { rollMany(20,1); assertEquals(20, g.score()); } // public void testOneSpare() throws Exception { // g.roll(5); // g.roll(5); // spare // g.roll(3); // rollMany(17,0); // assertEquals(16,g.score()); // } } public class Game { private int rolls[] = new int[21]; private int currentRoll = 0; public void roll(int pins) { rolls[currentRoll++] = pins; } public int score() { int score = 0; for (int i = 0; i < rolls.length; i++) score += rolls[i]; return score; } } - ugly comment in test. 37 

36 37 remove variable score from Game run the tests 

> remove variable score from Game ⏺ Update(src/main/java/Game.java) ───────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────── Edit file src/main/java/Game.java ╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌ 1 public class Game { 2 3 - private int score = 0; 3 private int[] rolls = new int[21]; 4 private int currentRoll = 0; 5 ╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌ Do you want to make this edit to Game.java? (Tab to add further instructions) ❯ 1. Yes 2. Yes, allow all edits during this session (shift+tab) 3. No Esc to cancel ⏺ Update(src/main/java/Game.java) ───────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────── Edit file src/main/java/Game.java ╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌ 4 private int currentRoll = 0; 5 6 public void roll(int pins) { 7 - score += pins; 7 rolls[currentRoll++] = pins; 8 } 9 ╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌ Do you want to make this edit to Game.java? (Tab to add further instructions) ❯ 1. Yes 2. Yes, allow all edits during this session (shift+tab) 3. No Esc to cancel ⏺ Removed the score field and the score += pins; line in roll. ───────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────── > run the tests 

> run the tests ⏺ Bash(mkdir -p build/classes build/test-classes && javac -d build/classes src/main/java/Game.java && javac -cp lib/junit-3.8.1.jar:build/classes -d build/test-classes…) ⎿ .. Time: 0.001 OK (2 tests) ⏺ 2 tests ran, all passing. ───────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────── > uncomment testOneSpare 

The Third test. import junit.framework.TestCase; public class BowlingGameTest extends TestCase { private Game g; protected void setUp() throws Exception { g = new Game(); } private void rollMany(int n, int pins) { for (int i = 0; i < n; i++) g.roll(pins); } public void testGutterGame() throws Exception { rollMany(20, 0); assertEquals(0, g.score()); } public void testAllOnes() throws Exception { rollMany(20,1); assertEquals(20, g.score()); } public void testOneSpare() throws Exception { g.roll(5); g.roll(5); // spare g.roll(3); rollMany(17,0); assertEquals(16,g.score()); } } public class Game { private int rolls[] = new int[21]; private int currentRoll = 0; public void roll(int pins) { rolls[currentRoll++] = pins; } public int score() { int score = 0; for (int i = 0; i < rolls.length; i++) score += rolls[i]; return score; } } - ugly comment in test. expected:<16> but was:<13> 38 

37 38 uncomment testOneSpare run the tests 

> uncomment testOneSpare ⏺ Update(src/test/java/Test.java) ───────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────── Edit file src/test/java/Test.java ╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌ 20 assertEquals(0, g.score()); 21 } 22 23 - // public void testOneSpare() { 24 - // g.roll(5); 25 - // g.roll(5); // spare 26 - // g.roll(3); 27 - // rollMany(17, 0); 28 - // assertEquals(16, g.score()); 29 - // } 23 + public void testOneSpare() { 24 + g.roll(5); 25 + g.roll(5); // spare 26 + g.roll(3); 27 + rollMany(17, 0); 28 + assertEquals(16, g.score()); 29 + } 30 31 public void testAllOnes() { 32 rollMany(20, 1); ╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌ Do you want to make this edit to Test.java? (Tab to add further instructions) ❯ 1. Yes 2. Yes, allow all edits during this session (shift+tab) 3. No Esc to cancel ⏺ Done — testOneSpare is uncommented. ───────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────── > run the tests 

> run the tests ⏺ Bash(mkdir -p build/classes build/test-classes && javac -d build/classes src/main/java/Game.java && javac -cp lib/junit-3.8.1.jar:build/classes -d build/test-classes…) ⎿ Error: Exit code 1 ..F. Time: 0.003 There was 1 failure: 1) testOneSpare(Test)junit.framework.AssertionFailedError: expected:<16> but was:<13> at Test.testOneSpare(Test.java:28) at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) … +2 lines (ctrl+o to see all) ⏺ testOneSpare fails — expected 16 but got 13. The spare bonus logic still needs to be implemented in score(). ───────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────── > 

The Third test. import junit.framework.TestCase; public class BowlingGameTest extends TestCase { private Game g; protected void setUp() throws Exception { g = new Game(); } private void rollMany(int n, int pins) { for (int i = 0; i < n; i++) g.roll(pins); } public void testGutterGame() throws Exception { rollMany(20, 0); assertEquals(0, g.score()); } public void testAllOnes() throws Exception { rollMany(20,1); assertEquals(20, g.score()); } public void testOneSpare() throws Exception { g.roll(5); g.roll(5); // spare g.roll(3); rollMany(17,0); assertEquals(16,g.score()); } } public class Game { private int rolls[] = new int[21]; private int currentRoll = 0; public void roll(int pins) { rolls[currentRoll++] = pins; } public int score() { int score = 0; for (int i = 0; i < rolls.length; i++) { if (rolls[i] + rolls[i+1] == 10) // spare score += ... score += rolls[i]; } return score; } } - ugly comment in test. This isn’t going to work because i might not refer to the first ball of the frame. Design is still wrong. Need to walk through array two balls (one frame) at a time. 39 

The Third test. import junit.framework.TestCase; public class BowlingGameTest extends TestCase { private Game g; protected void setUp() throws Exception { g = new Game(); } private void rollMany(int n, int pins) { for (int i = 0; i < n; i++) g.roll(pins); } public void testGutterGame() throws Exception { rollMany(20, 0); assertEquals(0, g.score()); } public void testAllOnes() throws Exception { rollMany(20,1); assertEquals(20, g.score()); } // public void testOneSpare() throws Exception { // g.roll(5); // g.roll(5); // spare // g.roll(3); // rollMany(17,0); // assertEquals(16,g.score()); // } } public class Game { private int rolls[] = new int[21]; private int currentRoll = 0; public void roll(int pins) { rolls[currentRoll++] = pins; } public int score() { int score = 0; for (int i = 0; i < rolls.length; i++) score += rolls[i]; return score; } } - ugly comment in test. 40 

38 40 comment out testOneSpare run the tests 

> comment out testOneSpare ⏺ Update(src/test/java/Test.java) ───────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────── Edit file src/test/java/Test.java ╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌ 20 assertEquals(0, g.score()); 21 } 22 23 - public void testOneSpare() { 24 - g.roll(5); 25 - g.roll(5); // spare 26 - g.roll(3); 27 - rollMany(17, 0); 28 - assertEquals(16, g.score()); 29 - } 23 + // public void testOneSpare() { 24 + // g.roll(5); 25 + // g.roll(5); // spare 26 + // g.roll(3); 27 + // rollMany(17, 0); 28 + // assertEquals(16, g.score()); 29 + // } 30 31 public void testAllOnes() { 32 rollMany(20, 1); ╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌ Do you want to make this edit to Test.java? (Tab to add further instructions) ❯ 1. Yes 2. Yes, allow all edits during this session (shift+tab) 3. No Esc to cancel ⏺ Done — testOneSpare is commented out. ───────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────── > 

> run the tests ⏺ Bash(mkdir -p build/classes build/test-classes && javac -d build/classes src/main/java/Game.java && javac -cp lib/junit-3.8.1.jar:build/classes -d build/test-classes…) ⎿ .. Time: 0.001 OK (2 tests) ⏺ 2 tests ran, all passing. ───────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────── > 

The Third test. import junit.framework.TestCase; public class BowlingGameTest extends TestCase { private Game g; protected void setUp() throws Exception { g = new Game(); } private void rollMany(int n, int pins) { for (int i = 0; i < n; i++) g.roll(pins); } public void testGutterGame() throws Exception { rollMany(20, 0); assertEquals(0, g.score()); } public void testAllOnes() throws Exception { rollMany(20,1); assertEquals(20, g.score()); } // public void testOneSpare() throws Exception { // g.roll(5); // g.roll(5); // spare // g.roll(3); // rollMany(17,0); // assertEquals(16,g.score()); // } } public class Game { private int rolls[] = new int[21]; private int currentRoll = 0; public void roll(int pins) { rolls[currentRoll++] = pins; } public int score() { int score = 0; int i = 0; for (int frame = 0; frame < 10; frame++) { score += rolls[i] + rolls[i+1]; i += 2; } return score; } } - ugly comment in test. 41 

40 41 > In the score method: (1) rename i to frame, except in the loop's body (2) change the exclusive upper bound of frame from rolls.length to 10 (3) before the loop, define integer variable i initialised to zero (4) change the loop's body from score += rolls[i]; to score += rolls[i] + rolls[i+1]; i+=2; 

> In the score method: (1) rename i to frame, except in the loop's body (2) change the exclusive upper bound of frame from rolls.length to 10 (3) before the loop, define integer variable i initialised to zero (4) change the loop's body from score += rolls[i]; to score += rolls[i] + rolls[i+1]; i+=2; ⏺ Update(src/main/java/Game.java) ──────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────── Edit file src/main/java/Game.java ╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌ 9 10 public int score() { 11 int score = 0; 12 - for (int i = 0; i < rolls.length; i++) { 13 - score += rolls[i]; 12 + int i = 0; 13 + for (int frame = 0; frame < 10; frame++) { 14 + score += rolls[i] + rolls[i + 1]; 15 + i += 2; 16 } 17 return score; 18 } ╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌ Do you want to make this edit to Game.java? (Tab to add further instructions) ❯ 1. Yes 2. Yes, allow all edits during this session (shift+tab) 3. No Esc to cancel ⏺ Done. ──────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────── > run the tests 

> run the tests ⏺ Bash(mkdir -p build/classes build/test-classes && javac -d build/classes src/main/java/Game.java && javac -cp lib/junit-3.8.1.jar:build/classes -d build/test-classes…) ⎿ .. Time: 0.001 OK (2 tests) ⏺ 2 tests ran, all passing. ───────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────── > 

The Third test. import junit.framework.TestCase; public class BowlingGameTest extends TestCase { private Game g; protected void setUp() throws Exception { g = new Game(); } private void rollMany(int n, int pins) { for (int i = 0; i < n; i++) g.roll(pins); } public void testGutterGame() throws Exception { rollMany(20, 0); assertEquals(0, g.score()); } public void testAllOnes() throws Exception { rollMany(20,1); assertEquals(20, g.score()); } public void testOneSpare() throws Exception { g.roll(5); g.roll(5); // spare g.roll(3); rollMany(17,0); assertEquals(16,g.score()); } } public class Game { private int rolls[] = new int[21]; private int currentRoll = 0; public void roll(int pins) { rolls[currentRoll++] = pins; } public int score() { int score = 0; int i = 0; for (int frame = 0; frame < 10; frame++) { score += rolls[i] + rolls[i+1]; i += 2; } return score; } } - ugly comment in test. expected:<16> but was:<13> 42 

41 42 uncomment testOneSpare run the tests 

> uncomment testOneSpare ⏺ Update(src/test/java/Test.java) ───────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────── Edit file src/test/java/Test.java ╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌ 20 assertEquals(0, g.score()); 21 } 22 23 - // public void testOneSpare() { 24 - // g.roll(5); 25 - // g.roll(5); // spare 26 - // g.roll(3); 27 - // rollMany(17, 0); 28 - // assertEquals(16, g.score()); 29 - // } 23 + public void testOneSpare() { 24 + g.roll(5); 25 + g.roll(5); // spare 26 + g.roll(3); 27 + rollMany(17, 0); 28 + assertEquals(16, g.score()); 29 + } 30 31 public void testAllOnes() { 32 rollMany(20, 1); ╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌ Do you want to make this edit to Test.java? (Tab to add further instructions) ❯ 1. Yes 2. Yes, allow all edits during this session (shift+tab) 3. No Esc to cancel ⏺ Done — testOneSpare is uncommented. ───────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────── > run the tests 

> run the tests ⏺ Bash(mkdir -p build/classes build/test-classes && javac -d build/classes src/main/java/Game.java && javac -cp lib/junit-3.8.1.jar:build/classes -d build/test-classes…) ⎿ Error: Exit code 1 ..F. Time: 0.003 There was 1 failure: 1) testOneSpare(Test)junit.framework.AssertionFailedError: expected:<16> but was:<13> at Test.testOneSpare(Test.java:28) at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) … +2 lines (ctrl+o to see all) ⏺ testOneSpare still fails — expected 16 but got 13. The spare bonus (adding the next roll after the frame) isn't handled yet in score(). ──────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────── > 

The Third test. import junit.framework.TestCase; public class BowlingGameTest extends TestCase { private Game g; protected void setUp() throws Exception { g = new Game(); } private void rollMany(int n, int pins) { for (int i = 0; i < n; i++) g.roll(pins); } public void testGutterGame() throws Exception { rollMany(20, 0); assertEquals(0, g.score()); } public void testAllOnes() throws Exception { rollMany(20,1); assertEquals(20, g.score()); } public void testOneSpare() throws Exception { g.roll(5); g.roll(5); // spare g.roll(3); rollMany(17,0); assertEquals(16,g.score()); } } public class Game { private int rolls[] = new int[21]; private int currentRoll = 0; public void roll(int pins) { rolls[currentRoll++] = pins; } public int score() { int score = 0; int i = 0; for (int frame = 0; frame < 10; frame++) { if (rolls[i] + rolls[i + 1] == 10) // spare { score += 10 + rolls[i + 2]; i += 2; } else { score += rolls[i] + rolls[i + 1]; i += 2; } } return score; } } - ugly comment in test. 43 

42 43 In the score method, change the body of the loop from score += rolls[i] + rolls[i + 1]; i += 2; to if (rolls[i] + rolls[i + 1] == 10) // spare { score += 10 + rolls[i + 2]; i += 2; } else { score += rolls[i] + rolls[i + 1]; i += 2; } run the tests 

> In the score method, change the body of the loop from score += rolls[i] + rolls[i + 1]; i += 2; to if (rolls[i] + rolls[i + 1] == 10) // spare { score += 10 + rolls[i + 2]; i += 2; } else { score += rolls[i] + rolls[i + 1]; i += 2; } ⏺ Update(src/main/java/Game.java) ──────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────── Edit file src/main/java/Game.java ╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌ 11 int score = 0; 12 int i = 0; 13 for (int frame = 0; frame < 10; frame++) { 14 - score += rolls[i] + rolls[i+1]; 15 - i += 2; 14 + if (rolls[i] + rolls[i + 1] == 10) // spare 15 + { 16 + score += 10 + rolls[i + 2]; 17 + i += 2; 18 + } else { 19 + score += rolls[i] + rolls[i + 1]; 20 + i += 2; 21 + } 22 } 23 return score; 24 } ╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌ Do you want to make this edit to Game.java? (Tab to add further instructions) ❯ 1. Yes 2. Yes, allow all edits during this session (shift+tab) 3. No Esc to cancel ⏺ Done — added spare handling in the score() loop. ──────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────── > run the tests 

> run the tests ⏺ Bash(mkdir -p build/classes build/test-classes && javac -d build/classes src/main/java/Game.java && javac -cp lib/junit-3.8.1.jar:build/classes -d build/test-classes…) ⎿ ... Time: 0.001 OK (3 tests) ⏺ 3 tests ran, all passing. ──────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────── > Write new test testOneStrike 

The Third test. import junit.framework.TestCase; public class BowlingGameTest extends TestCase { private Game g; protected void setUp() throws Exception { g = new Game(); } private void rollMany(int n, int pins) { for (int i = 0; i < n; i++) g.roll(pins); } public void testGutterGame() throws Exception { rollMany(20, 0); assertEquals(0, g.score()); } public void testAllOnes() throws Exception { rollMany(20,1); assertEquals(20, g.score()); } public void testOneSpare() throws Exception { g.roll(5); g.roll(5); // spare g.roll(3); rollMany(17,0); assertEquals(16,g.score()); } } public class Game { private int rolls[] = new int[21]; private int currentRoll = 0; public void roll(int pins) { rolls[currentRoll++] = pins; } public int score() { int score = 0; int i = 0; for (int frame = 0; frame < 10; frame++) { if (rolls[i] + rolls[i + 1] == 10) // spare { score += 10 + rolls[i + 2]; i += 2; } else { score += rolls[i] + rolls[i + 1]; i += 2; } } return score; } } - ugly comment in test. - ugly comment in conditional. - i is a bad name for this variable 44 

The Third test. import junit.framework.TestCase; public class BowlingGameTest extends TestCase { private Game g; protected void setUp() throws Exception { g = new Game(); } private void rollMany(int n, int pins) { for (int i = 0; i < n; i++) g.roll(pins); } public void testGutterGame() throws Exception { rollMany(20, 0); assertEquals(0, g.score()); } public void testAllOnes() throws Exception { rollMany(20,1); assertEquals(20, g.score()); } public void testOneSpare() throws Exception { g.roll(5); g.roll(5); // spare g.roll(3); rollMany(17,0); assertEquals(16,g.score()); } } public class Game { private int rolls[] = new int[21]; private int currentRoll = 0; public void roll(int pins) { rolls[currentRoll++] = pins; } public int score() { int score = 0; int frameIndex = 0; for (int frame = 0; frame < 10; frame++) { if (rolls[frameIndex] + rolls[frameIndex + 1] == 10) // spare { score += 10 + rolls[frameIndex + 2]; frameIndex += 2; } else { score += rolls[frameIndex] + rolls[frameIndex + 1]; frameIndex += 2; } } return score; } } - ugly comment in test. - ugly comment in conditional. 45 

rename i to frameIndex in score method run the tests 44 45 

> rename i to frameIndex in score method ⏺ Read(src/main/java/Game.java) ⎿ Read 26 lines ⏺ Update(src/main/java/Game.java) ──────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────── Edit file src/main/java/Game.java ╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌ 9 10 public int score() { 11 int score = 0; 12 - int i = 0; 12 + int frameIndex = 0; 13 for (int frame = 0; frame < 10; frame++) { 14 - if (rolls[i] + rolls[i + 1] == 10) // spare 14 + if (rolls[frameIndex] + rolls[frameIndex + 1] == 10) // spare 15 { 16 - score += 10 + rolls[i + 2]; 17 - i += 2; 16 + score += 10 + rolls[frameIndex + 2]; 17 + frameIndex += 2; 18 } else { 19 - score += rolls[i] + rolls[i + 1]; 20 - i += 2; 19 + score += rolls[frameIndex] + rolls[frameIndex + 1]; 20 + frameIndex += 2; 21 } 22 } 23 return score; ╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌ Do you want to make this edit to Game.java? (Tab to add further instructions) ❯ 1. Yes 2. Yes, allow all edits during this session (shift+tab) 3. No Esc to cancel ⏺ Done — renamed i to frameIndex throughout the score() method. ──────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────── > run the tests 

> run the tests ⏺ Bash(mkdir -p build/classes build/test-classes && javac -d build/classes src/main/java/Game.java && javac -cp lib/junit-3.8.1.jar:build/classes -d build/test-classes…) ⎿ ... Time: 0.001 OK (3 tests) ⏺ 3 tests ran, all passing. ──────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────── > Add a test for a strike 

The Third test. import junit.framework.TestCase; public class BowlingGameTest extends TestCase { private Game g; protected void setUp() throws Exception { g = new Game(); } private void rollMany(int n, int pins) { for (int i = 0; i < n; i++) g.roll(pins); } public void testGutterGame() throws Exception { rollMany(20, 0); assertEquals(0, g.score()); } public void testAllOnes() throws Exception { rollMany(20,1); assertEquals(20, g.score()); } public void testOneSpare() throws Exception { g.roll(5); g.roll(5); // spare g.roll(3); rollMany(17,0); assertEquals(16,g.score()); } } public class Game { private int rolls[] = new int[21]; private int currentRoll = 0; public void roll(int pins) { rolls[currentRoll++] = pins; } public int score() { int score = 0; int frameIndex = 0; for (int frame = 0; frame < 10; frame++) { if (isSpare(frameIndex)) { score += 10 + rolls[frameIndex + 2]; frameIndex += 2; } else { score += rolls[frameIndex] + rolls[frameIndex + 1]; frameIndex += 2; } } return score; } private boolean isSpare(int frameIndex) { return rolls[frameIndex] + rolls[frameIndex + 1] == 10; } } - ugly comment in test. 46 

perform an 'extract method' refactoring on the boolean expression that is tested in the conditional in the score() method, calling the new method 'isSpare' run the tests 45 46 

> perform an 'extract method' refactoring on the boolean expression that is tested in the conditional in the score() method, calling the new method 'isSpare' ⏺ Update(src/main/java/Game.java) ──────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────── Edit file src/main/java/Game.java ╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌ 11 int score = 0; 12 int frameIndex = 0; 13 for (int frame = 0; frame < 10; frame++) { 14 - if (rolls[frameIndex] + rolls[frameIndex + 1] == 10) // spare 14 + if (isSpare(frameIndex)) 15 { 16 score += 10 + rolls[frameIndex + 2]; 17 frameIndex += 2; ╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌ Do you want to make this edit to Game.java? (Tab to add further instructions) ❯ 1. Yes 2. Yes, allow all edits during this session (shift+tab) 3. No Esc to cancel ⏺ Update(src/main/java/Game.java) ──────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────── Edit file src/main/java/Game.java ╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌ 7 rolls[currentRoll++] = pins; 8 } 9 10 + private boolean isSpare(int frameIndex) { 11 + return rolls[frameIndex] + rolls[frameIndex + 1] == 10; 12 + } 13 + 14 public int score() { 15 int score = 0; 16 int frameIndex = 0; ╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌ Do you want to make this edit to Game.java? (Tab to add further instructions) ❯ 1. Yes 2. Yes, allow all edits during this session (shift+tab) 3. No Esc to cancel ⏺ Done — extracted isSpare method and replaced the boolean expression with a call to it. ──────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────── > run the tests 

⏺ Done — extracted isSpare method and replaced the boolean expression with a call to it. ──────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────── > run the tests > run the tests ⏺ Bash(mkdir -p build/classes build/test-classes && javac -d build/classes src/main/java/Game.java && javac -cp lib/junit-3.8.1.jar:build/classes -d build/test-classes…) ⎿ ... Time: 0.001 OK (3 tests) ⏺ 3 tests ran, all passing. ──────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────── > Add a test for a strike 

The Third test. import junit.framework.TestCase; public class BowlingGameTest extends TestCase { private Game g; protected void setUp() throws Exception { g = new Game(); } private void rollMany(int n, int pins) { for (int i = 0; i < n; i++) g.roll(pins); } public void testGutterGame() throws Exception { rollMany(20, 0); assertEquals(0, g.score()); } public void testAllOnes() throws Exception { rollMany(20,1); assertEquals(20, g.score()); } public void testOneSpare() throws Exception { rollSpare(); g.roll(3); rollMany(17,0); assertEquals(16,g.score()); } private void rollSpare() { g.roll(5); g.roll(5); } } public class Game { private int rolls[] = new int[21]; private int currentRoll = 0; public void roll(int pins) { rolls[currentRoll++] = pins; } public int score() { int score = 0; int frameIndex = 0; for (int frame = 0; frame < 10; frame++) { if (isSpare(frameIndex)) { score += 10 + rolls[frameIndex + 2]; frameIndex += 2; } else { score += rolls[frameIndex] + rolls[frameIndex + 1]; frameIndex += 2; } } return score; } private boolean isSpare(int frameIndex) { return rolls[frameIndex] + rolls[frameIndex + 1] == 10; } } - 47 

extract from testOneSpare a method called rollSpare that rolls two fives run the tests 46 47 

⏺ Done — extracted rollSpare() and replaced the two g.roll(5) calls in testOneSpare with it. ──────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────── > run the tests > extract from testOneSpare a method called rollSpare that rolls two fives ⏺ Read(src/test/java/Test.java) ⎿ Read 36 lines ⏺ Update(src/test/java/Test.java) ──────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────── Edit file src/test/java/Test.java ╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌ 20 assertEquals(0, g.score()); 21 } 22 23 - public void testOneSpare() { 23 + private void rollSpare() { 24 g.roll(5); 25 - g.roll(5); // spare 25 + g.roll(5); 26 + } 27 + 28 + public void testOneSpare() { 29 + rollSpare(); 30 g.roll(3); 31 rollMany(17, 0); 32 assertEquals(16, g.score()); ╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌ Do you want to make this edit to Test.java? (Tab to add further instructions) ❯ 1. Yes 2. Yes, allow all edits during this session (shift+tab) 3. No Esc to cancel 

⏺ Done — extracted isSpare method and replaced the boolean expression with a call to it. ──────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────── > run the tests > run the tests ⏺ Bash(mkdir -p build/classes build/test-classes && javac -d build/classes src/main/java/Game.java && javac -cp lib/junit-3.8.1.jar:build/classes -d build/test-classes…) ⎿ ... Time: 0.001 OK (3 tests) ⏺ 3 tests ran, all passing. ──────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────── > Add a test for a strike 

The Fourth test. import junit.framework.TestCase; public class BowlingGameTest extends TestCase { ... public void testGutterGame() throws Exception { rollMany(20, 0); assertEquals(0, g.score()); } public void testAllOnes() throws Exception { rollMany(20,1); assertEquals(20, g.score()); } public void testOneSpare() throws Exception { rollSpare(); g.roll(3); rollMany(17,0); assertEquals(16,g.score()); } public void testOneStrike() throws Exception { g.roll(10); // strike g.roll(3); g.roll(4); rollMany(16, 0); assertEquals(24, g.score()); } private void rollSpare() { g.roll(5); g.roll(5); } } public class Game { private int rolls[] = new int[21]; private int currentRoll = 0; public void roll(int pins) { rolls[currentRoll++] = pins; } public int score() { int score = 0; int frameIndex = 0; for (int frame = 0; frame < 10; frame++) { if (isSpare(frameIndex)) { score += 10 + rolls[frameIndex + 2]; frameIndex += 2; } else { score += rolls[frameIndex] + rolls[frameIndex + 1]; frameIndex += 2; } } return score; } private boolean isSpare(int frameIndex) { return rolls[frameIndex] + rolls[frameIndex + 1] == 10; } } - ugly comment in testOneStrike. expected:<24> but was:<17> 48 

Add the following test public void testOneStrike() throws Exception { g.roll(10); // strike g.roll(3); g.roll(4); rollMany(16, 0); assertEquals(24, g.score()); } run the tests 47 48 

> Add the following test public void testOneStrike() throws Exception { g.roll(10); // strike g.roll(3); g.roll(4); rollMany(16, 0); assertEquals(24, g.score()); } ⏺ Update(src/test/java/Test.java) ──────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────── Edit file src/test/java/Test.java ╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌ 32 assertEquals(16, g.score()); 33 } 34 35 + public void testOneStrike() throws Exception { 36 + g.roll(10); // strike 37 + g.roll(3); 38 + g.roll(4); 39 + rollMany(16, 0); 40 + assertEquals(24, g.score()); 41 + } 42 + 43 public void testAllOnes() { 44 rollMany(20, 1); 45 assertEquals(20, g.score()); ╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌ Do you want to make this edit to Test.java? (Tab to add further instructions) ❯ 1. Yes 2. Yes, allow all edits during this session (shift+tab) 3. No Esc to cancel ⏺ Added testOneStrike. ──────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────── > run the tests 

> run the tests ⏺ Bash(mkdir -p build/classes build/test-classes && javac -d build/classes src/main/java/Game.java && javac -cp lib/junit-3.8.1.jar:build/classes -d build/test-classes…) ⎿ Error: Exit code 1 ..F.. Time: 0.003 There was 1 failure: 1) testOneStrike(Test)junit.framework.AssertionFailedError: expected:<24> but was:<17> at Test.testOneStrike(Test.java:40) at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) … +2 lines (ctrl+o to see all) ⏺ testOneStrike fails — expected 24 but got 17. The strike bonus logic isn't implemented yet in score(). ──────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────── > add strike handling to the score method 

The Fourth test. import junit.framework.TestCase; public class BowlingGameTest extends TestCase { ... public void testGutterGame() throws Exception { rollMany(20, 0); assertEquals(0, g.score()); } public void testAllOnes() throws Exception { rollMany(20,1); assertEquals(20, g.score()); } public void testOneSpare() throws Exception { rollSpare(); g.roll(3); rollMany(17,0); assertEquals(16,g.score()); } public void testOneStrike() throws Exception { g.roll(10); // strike g.roll(3); g.roll(4); rollMany(16, 0); assertEquals(24, g.score()); } private void rollSpare() { g.roll(5); g.roll(5); } } public class Game { private int rolls[] = new int[21]; private int currentRoll = 0; public void roll(int pins) { rolls[currentRoll++] = pins; } public int score() { int score = 0; int frameIndex = 0; for (int frame = 0; frame < 10; frame++) { if (rolls[frameIndex] == 10) // strike { score += 10 + rolls[frameIndex+1] + rolls[frameIndex+2]; frameIndex++; } else if (isSpare(frameIndex)) { score += 10 + rolls[frameIndex + 2]; frameIndex += 2; } else { score += rolls[frameIndex] + rolls[frameIndex + 1]; frameIndex += 2; } } return score; } private boolean isSpare(int frameIndex) { return rolls[frameIndex] + rolls[frameIndex + 1] == 10; } } - ugly comment in testOneStrike. - ugly comment in conditional. - ugly expressions. 49 

prefix the conditional in score() with the following: if (rolls[frameIndex] == 10) // strike { score += 10 + rolls[frameIndex+1] + rolls[frameIndex+2]; frameIndex++; } else run the tests 48 49 

> prefix the conditional in score() with the following: if (rolls[frameIndex] == 10) // strike { score += 10 + rolls[frameIndex+1] + rolls[frameIndex+2]; frameIndex++; } else ⏺ Update(src/main/java/Game.java) ──────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────── Edit file src/main/java/Game.java ╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌ 15 int score = 0; 16 int frameIndex = 0; 17 for (int frame = 0; frame < 10; frame++) { 18 - if (isSpare(frameIndex)) 18 + if (rolls[frameIndex] == 10) // strike 19 { 20 + score += 10 + 21 + rolls[frameIndex+1] + 22 + rolls[frameIndex+2]; 23 + frameIndex++; 24 + } 25 + else if (isSpare(frameIndex)) 26 + { 27 score += 10 + rolls[frameIndex + 2]; 28 frameIndex += 2; 29 } else { ╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌ Do you want to make this edit to Game.java? (Tab to add further instructions) ❯ 1. Yes 2. Yes, allow all edits during this session (shift+tab) 3. No Esc to cancel ⏺ Done — added strike handling before the spare conditional. ──────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────── > run the tests 

> run the tests ⏺ Bash(mkdir -p build/classes build/test-classes && javac -d build/classes src/main/java/Game.java && javac -cp lib/junit-3.8.1.jar:build/classes -d build/test-classes…) ⎿ .... Time: 0.002 OK (4 tests) ⏺ 4 tests ran, all passing. ──────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────── > 

The Fourth test. import junit.framework.TestCase; public class BowlingGameTest extends TestCase { ... public void testGutterGame() throws Exception { rollMany(20, 0); assertEquals(0, g.score()); } public void testAllOnes() throws Exception { rollMany(20,1); assertEquals(20, g.score()); } public void testOneSpare() throws Exception { rollSpare(); g.roll(3); rollMany(17,0); assertEquals(16,g.score()); } public void testOneStrike() throws Exception { g.roll(10); // strike g.roll(3); g.roll(4); rollMany(16, 0); assertEquals(24, g.score()); } private void rollSpare() { g.roll(5); g.roll(5); } } public class Game { private int rolls[] = new int[21]; private int currentRoll = 0; public void roll(int pins) { rolls[currentRoll++] = pins; } public int score() { int score = 0; int frameIndex = 0; for (int frame = 0; frame < 10; frame++) { if (rolls[frameIndex] == 10) // strike { score += 10 + strikeBonus(frameIndex); frameIndex++; } else if (isSpare(frameIndex)) { score += 10 + spareBonus(frameIndex); frameIndex += 2; } else { score += sumOfBallsInFrame(frameIndex); frameIndex += 2; } } return score; } private int sumOfBallsInFrame(int frameIndex) { return rolls[frameIndex]+rolls[frameIndex+1]; } private int spareBonus(int frameIndex) { return rolls[frameIndex + 2]; } private int strikeBonus(int frameIndex) { return rolls[frameIndex+1]+rolls[frameIndex+2]; } private boolean isSpare(int frameIndex) { return rolls[frameIndex]+rolls[frameIndex+1] == 10; } } - ugly comment in testOneStrike. - ugly comment in conditional. 50 

extract the following functions from the body of method score(): private int sumOfBallsInFrame(int frameIndex) { return rolls[frameIndex]+rolls[frameIndex+1]; } private int spareBonus(int frameIndex) { return rolls[frameIndex + 2]; } private int strikeBonus(int frameIndex) { return rolls[frameIndex+1]+rolls[frameIndex+2]; } run the tests 49 50 

> extract the following functions from the body of method score(): private int sumOfBallsInFrame(int frameIndex) { return rolls[frameIndex]+rolls[frameIndex+1]; } private int spareBonus(int frameIndex) { return rolls[frameIndex + 2]; } private int strikeBonus(int frameIndex) { return rolls[frameIndex+1]+rolls[frameIndex+2]; } ⏺ Read(src/main/java/Game.java) ⎿ Read 37 lines ⏺ Update(src/main/java/Game.java) ──────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────── Edit file src/main/java/Game.java ╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌ 11 return rolls[frameIndex] + rolls[frameIndex + 1] == 10; 12 } 13 14 + private int sumOfBallsInFrame(int frameIndex) { 15 + return rolls[frameIndex]+rolls[frameIndex+1]; 16 + } 17 + 18 + private int spareBonus(int frameIndex) { 19 + return rolls[frameIndex + 2]; 20 + } 21 + 22 + private int strikeBonus(int frameIndex) { 23 + return rolls[frameIndex+1]+rolls[frameIndex+2]; 24 + } 25 + 26 public int score() { 27 int score = 0; 28 int frameIndex = 0; ╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌ Do you want to make this edit to Game.java? (Tab to add further instructions) ❯ 1. Yes 2. Yes, allow all edits during this session (shift+tab) 3. No Esc to cancel 

⏺ Update(src/main/java/Game.java) ──────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────── Edit file src/main/java/Game.java ╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌ 29 for (int frame = 0; frame < 10; frame++) { 30 if (rolls[frameIndex] == 10) // strike 31 { 32 - score += 10 + 33 - rolls[frameIndex+1] + 34 - rolls[frameIndex+2]; 32 + score += 10 + strikeBonus(frameIndex); 33 frameIndex++; 34 } 35 else if (isSpare(frameIndex)) ╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌ Do you want to make this edit to Game.java? (Tab to add further instructions) ❯ 1. Yes 2. Yes, allow all edits during this session (shift+tab) 3. No Esc to cancel ⏺ Update(src/main/java/Game.java) ──────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────── Edit file src/main/java/Game.java ╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌ 34 } 35 else if (isSpare(frameIndex)) 36 { 37 - score += 10 + rolls[frameIndex + 2]; 37 + score += 10 + spareBonus(frameIndex); 38 frameIndex += 2; 39 } else { 40 score += rolls[frameIndex] + rolls[frameIndex + 1]; ╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌ Do you want to make this edit to Game.java? (Tab to add further instructions) ❯ 1. Yes 2. Yes, allow all edits during this session (shift+tab) 3. No Esc to cancel 

⏺ Update(src/main/java/Game.java) ──────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────── Edit file src/main/java/Game.java ╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌ 37 score += 10 + spareBonus(frameIndex); 38 frameIndex += 2; 39 } else { 40 - score += rolls[frameIndex] + rolls[frameIndex + 1]; 40 + score += sumOfBallsInFrame(frameIndex); 41 frameIndex += 2; 42 } 43 } ╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌ Do you want to make this edit to Game.java? (Tab to add further instructions) ❯ 1. Yes 2. Yes, allow all edits during this session (shift+tab) 3. No Esc to cancel ⏺ Done — extracted sumOfBallsInFrame, spareBonus, and strikeBonus methods and replaced the inline expressions in score(). ──────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────── > run the tests > run the tests ⏺ Bash(mkdir -p build/classes build/test-classes && javac -d build/classes src/main/java/Game.java && javac -cp lib/junit-3.8.1.jar:build/classes -d build/test-classes…) ⎿ .... Time: 0.002 OK (4 tests) ⏺ 4 tests ran, all passing. ──────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────── > 

The Fourth test. import junit.framework.TestCase; public class BowlingGameTest extends TestCase { ... public void testGutterGame() throws Exception { rollMany(20, 0); assertEquals(0, g.score()); } public void testAllOnes() throws Exception { rollMany(20,1); assertEquals(20, g.score()); } public void testOneSpare() throws Exception { rollSpare(); g.roll(3); rollMany(17,0); assertEquals(16,g.score()); } public void testOneStrike() throws Exception { g.roll(10); // strike g.roll(3); g.roll(4); rollMany(16, 0); assertEquals(24, g.score()); } private void rollSpare() { g.roll(5); g.roll(5); } } public class Game { private int rolls[] = new int[21]; private int currentRoll = 0; public void roll(int pins) { rolls[currentRoll++] = pins; } public int score() { int score = 0; int frameIndex = 0; for (int frame = 0; frame < 10; frame++) { if (isStrike(frameIndex)) { score += 10 + strikeBonus(frameIndex); frameIndex++; } else if (isSpare(frameIndex)) { score += 10 + spareBonus(frameIndex); frameIndex += 2; } else { score += sumOfBallsInFrame(frameIndex); frameIndex += 2; } } return score; } private boolean isStrike(int frameIndex) { return rolls[frameIndex] == 10; } private int sumOfBallsInFrame(int frameIndex) { return rolls[frameIndex] + rolls[frameIndex+1]; } private int spareBonus(int frameIndex) { return rolls[frameIndex+2]; } private int strikeBonus(int frameIndex) { return rolls[frameIndex+1] + rolls[frameIndex+2]; } private boolean isSpare(int frameIndex) { return rolls[frameIndex]+rolls[frameIndex+1] == 10; } } - ugly comment in testOneStrike. 51 

extract the following into method isStrike: rolls[frameIndex] == 10 run the tests 50 51 

> extract the following into method isStrike: rolls[frameIndex] == 10 ⏺ Update(src/main/java/Game.java) ──────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────── Edit file src/main/java/Game.java ╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌ 7 rolls[currentRoll++] = pins; 8 } 9 10 + private boolean isStrike(int frameIndex) { 11 + return rolls[frameIndex] == 10; 12 + } 13 + 14 private boolean isSpare(int frameIndex) { 15 return rolls[frameIndex] + rolls[frameIndex + 1] == 10; 16 } ╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌ Do you want to make this edit to Game.java? (Tab to add further instructions) ❯ 1. Yes 2. Yes, allow all edits during this session (shift+tab) 3. No Esc to cancel ⏺ Update(src/main/java/Game.java) ───────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────── Edit file src/main/java/Game.java ╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌ 31 int score = 0; 32 int frameIndex = 0; 33 for (int frame = 0; frame < 10; frame++) { 34 - if (rolls[frameIndex] == 10) // strike 34 + if (isStrike(frameIndex)) 35 { 36 score += 10 + strikeBonus(frameIndex); 37 frameIndex++; ╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌ Do you want to make this edit to Game.java? (Tab to add further instructions) ❯ 1. Yes 2. Yes, allow all edits during this session (shift+tab) 3. No Esc to cancel ⏺ Done — extracted isStrike method and replaced the inline expression. ───────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────── > run the tests 

> run the tests ⏺ Bash(mkdir -p build/classes build/test-classes && javac -d build/classes src/main/java/Game.java && javac -cp lib/junit-3.8.1.jar:build/classes -d build/test-classes…) ⎿ .... Time: 0.002 OK (4 tests) ⏺ 4 tests ran, all passing. ──────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────── > 

The Fourth test. ... public void testGutterGame() throws Exception { rollMany(20, 0); assertEquals(0, g.score()); } public void testAllOnes() throws Exception { rollMany(20,1); assertEquals(20, g.score()); } public void testOneSpare() throws Exception { rollSpare(); g.roll(3); rollMany(17,0); assertEquals(16,g.score()); } public void testOneStrike() throws Exception { rollStrike(); g.roll(3); g.roll(4); rollMany(16, 0); assertEquals(24, g.score()); } private void rollStrike() { g.roll(10); } private void rollSpare() { g.roll(5); g.roll(5); } } public class Game { private int rolls[] = new int[21]; private int currentRoll = 0; public void roll(int pins) { rolls[currentRoll++] = pins; } public int score() { int score = 0; int frameIndex = 0; for (int frame = 0; frame < 10; frame++) { if (isStrike(frameIndex)) { score += 10 + strikeBonus(frameIndex); frameIndex++; } else if (isSpare(frameIndex)) { score += 10 + spareBonus(frameIndex); frameIndex += 2; } else { score += sumOfBallsInFrame(frameIndex); frameIndex += 2; } } return score; } private boolean isStrike(int frameIndex) { return rolls[frameIndex] == 10; } private int sumOfBallsInFrame(int frameIndex) { return rolls[frameIndex] + rolls[frameIndex+1]; } private int spareBonus(int frameIndex) { return rolls[frameIndex+2]; } private int strikeBonus(int frameIndex) { return rolls[frameIndex+1] + rolls[frameIndex+2]; } private boolean isSpare(int frameIndex) { return rolls[frameIndex]+rolls[frameIndex+1] == 10; } } 52 

extract g.roll(10) into method rollStrike run the tests 51 52 

> extract g.roll(10) into method rollStrike ⏺ Update(src/test/java/Test.java) ───────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────── Edit file src/test/java/Test.java ╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌ 33 } 34 35 public void testOneStrike() throws Exception { 36 - g.roll(10); // strike 36 + rollStrike(); 37 g.roll(3); 38 g.roll(4); 39 rollMany(16, 0); ╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌ Do you want to make this edit to Test.java? (Tab to add further instructions) ❯ 1. Yes 2. Yes, allow all edits during this session (shift+tab) 3. No Esc to cancel ⏺ Update(src/test/java/Test.java) ────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────── Edit file src/test/java/Test.java ╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌ 25 g.roll(5); 26 } 27 28 + private void rollStrike() { 29 + g.roll(10); 30 + } 31 + 32 public void testOneSpare() { 33 rollSpare(); 34 g.roll(3); ╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌ Do you want to make this edit to Test.java? (Tab to add further instructions) ❯ 1. Yes 2. Yes, allow all edits during this session (shift+tab) 3. No Esc to cancel ⏺ Done — extracted rollStrike method. ────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────── > run the tests 

> run the tests ⏺ Bash(mkdir -p build/classes build/test-classes && javac -d build/classes src/main/java/Game.java && javac -cp lib/junit-3.8.1.jar:build/classes -d build/test-classes…) ⎿ .... Time: 0.002 OK (4 tests) ⏺ 4 tests ran, all passing. ──────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────── > 

The Fifth test. ... public void testGutterGame() throws Exception { rollMany(20, 0); assertEquals(0, g.score()); } public void testAllOnes() throws Exception { rollMany(20,1); assertEquals(20, g.score()); } public void testOneSpare() throws Exception { rollSpare(); g.roll(3); rollMany(17,0); assertEquals(16,g.score()); } public void testOneStrike() throws Exception { rollStrike(); g.roll(3); g.roll(4); rollMany(16, 0); assertEquals(24, g.score()); } public void testPerfectGame() throws Exception { rollMany(12,10); assertEquals(300, g.score()); } private void rollStrike() { g.roll(10); } private void rollSpare() { g.roll(5); g.roll(5); } } public class Game { private int rolls[] = new int[21]; private int currentRoll = 0; public void roll(int pins) { rolls[currentRoll++] = pins; } public int score() { int score = 0; int frameIndex = 0; for (int frame = 0; frame < 10; frame++) { if (isStrike(frameIndex)) { score += 10 + strikeBonus(frameIndex); frameIndex++; } else if (isSpare(frameIndex)) { score += 10 + spareBonus(frameIndex); frameIndex += 2; } else { score += sumOfBallsInFrame(frameIndex); frameIndex += 2; } } return score; } private boolean isStrike(int frameIndex) { return rolls[frameIndex] == 10; } private int sumOfBallsInFrame(int frameIndex) { return rolls[frameIndex] + rolls[frameIndex+1]; } private int spareBonus(int frameIndex) { return rolls[frameIndex+2]; } private int strikeBonus(int frameIndex) { return rolls[frameIndex+1] + rolls[frameIndex+2]; } private boolean isSpare(int frameIndex) { return rolls[frameIndex]+rolls[frameIndex+1] == 10; } } 53 

Add this final test: public void testPerfectGame() throws Exception { rollMany(12,10); assertEquals(300, g.score()); } run the tests 52 53 

> Add this final test: public void testPerfectGame() throws Exception { rollMany(12,10); assertEquals(300, g.score()); } ⏺ Update(src/test/java/Test.java) ────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────── Edit file src/test/java/Test.java ╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌ 44 assertEquals(24, g.score()); 45 } 46 47 + public void testPerfectGame() throws Exception { 48 + rollMany(12,10); 49 + assertEquals(300, g.score()); 50 + } 51 + 52 public void testAllOnes() { 53 rollMany(20, 1); 54 assertEquals(20, g.score()); ╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌ Do you want to make this edit to Test.java? (Tab to add further instructions) ❯ 1. Yes 2. Yes, allow all edits during this session (shift+tab) 3. No Esc to cancel ⏺ Added testPerfectGame. ────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────── > run the tests 

> run the tests ⏺ Bash(mkdir -p build/classes build/test-classes && javac -d build/classes src/main/java/Game.java && javac -cp lib/junit-3.8.1.jar:build/classes -d build/test- classes…) ⎿ ..... Time: 0.001 OK (5 tests) ⏺ 5 tests ran, all passing. ────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────── > show me Game.java 

End 54 

In the next slide we tell Claude to show the final code. The subsequent slide is the final one, and shows the same code, but with methods grouped according to their access modifiers (private/public), and with a splash of colour added to aid comprehension. 

> show me Game.java ⏺ Read(src/main/java/Game.java) ⎿ Read 51 lines ⏺ public class Game { private int[] rolls = new int[21]; private int currentRoll = 0; public void roll(int pins) { rolls[currentRoll++] = pins; } private boolean isStrike(int frameIndex) { return rolls[frameIndex] == 10; } private boolean isSpare(int frameIndex) { return rolls[frameIndex] + rolls[frameIndex + 1] == 10; } private int sumOfBallsInFrame(int frameIndex) { return rolls[frameIndex]+rolls[frameIndex+1]; } private int spareBonus(int frameIndex) { return rolls[frameIndex + 2]; } private int strikeBonus(int frameIndex) { return rolls[frameIndex+1]+rolls[frameIndex+2]; } public int score() { int score = 0; int frameIndex = 0; for (int frame = 0; frame < 10; frame++) { if (isStrike(frameIndex)) { score += 10 + strikeBonus(frameIndex); frameIndex++; } else if (isSpare(frameIndex)) { score += 10 + spareBonus(frameIndex); frameIndex += 2; } else { score += sumOfBallsInFrame(frameIndex); frameIndex += 2; } } return score; } } ────────────────────────────────────────────────────────────────────────── > show me Test.java ⏺ Read(src/test/java/Test.java) ⎿ Read 57 lines ⏺ import junit.framework.TestCase; public class Test extends TestCase { private Game g; protected void setUp() throws Exception { super.setUp(); g = new Game(); } private void rollMany(int n, int pins) { for (int i = 0; i < n; i++) { g.roll(pins); } } public void testGutterGame() { rollMany(20, 0); assertEquals(0, g.score()); } private void rollSpare() { g.roll(5); g.roll(5); } private void rollStrike() { g.roll(10); } public void testOneSpare() { rollSpare(); g.roll(3); rollMany(17, 0); assertEquals(16, g.score()); } public void testOneStrike() throws Exception { rollStrike(); g.roll(3); g.roll(4); rollMany(16, 0); assertEquals(24, g.score()); } public void testPerfectGame() throws Exception { rollMany(12,10); assertEquals(300, g.score()); } public void testAllOnes() { rollMany(20, 1); assertEquals(20, g.score()); } } ────────────────────────────────────────────────────────────────────────── 

public class Game { private int[] rolls = new int[21]; private int currentRoll = 0; private boolean isStrike(int frameIndex) { return rolls[frameIndex] == 10; } private boolean isSpare(int frameIndex) { return rolls[frameIndex] + rolls[frameIndex + 1] == 10; } private int sumOfBallsInFrame(int frameIndex) { return rolls[frameIndex]+rolls[frameIndex+1]; } private int spareBonus(int frameIndex) { return rolls[frameIndex + 2]; } private int strikeBonus(int frameIndex) { return rolls[frameIndex+1]+rolls[frameIndex+2]; } public void roll(int pins) { rolls[currentRoll++] = pins; } public int score() { int score = 0; int frameIndex = 0; for (int frame = 0; frame < 10; frame++) { if (isStrike(frameIndex)) { score += 10 + strikeBonus(frameIndex); frameIndex++; } else if (isSpare(frameIndex)) { score += 10 + spareBonus(frameIndex); frameIndex += 2; } else { score += sumOfBallsInFrame(frameIndex); frameIndex += 2; } } return score; } } import junit.framework.TestCase; public class Test extends TestCase { private Game g; protected void setUp() throws Exception { super.setUp(); g = new Game(); } private void rollMany(int n, int pins) { for (int i = 0; i < n; i++) { g.roll(pins); } } private void rollSpare() { g.roll(5); g.roll(5); } private void rollStrike() { g.roll(10); } public void testGutterGame() { rollMany(20, 0); assertEquals(0, g.score()); } public void testAllOnes() { rollMany(20, 1); assertEquals(20, g.score()); } public void testOneSpare() { rollSpare(); g.roll(3); rollMany(17, 0); assertEquals(16, g.score()); } public void testOneStrike() throws Exception { rollStrike(); g.roll(3); g.roll(4); rollMany(16, 0); assertEquals(24, g.score()); } public void testPerfectGame() throws Exception { rollMany(12,10); assertEquals(300, g.score()); } } 

That’s all. I hope you found it useful.