2014 Graduate Bootcamp: More TDD

Mocks & stubs; acceptance test frameworks; web app testing

Transcript

1. More TDD
2. Test doubles
3. Test doubles Acceptance test tools
4. Test doubles Acceptance test tools Testing web apps
5. Test doubles
6. Test doubles (stubs and mocks)
7. Test doubles (stubs and mocks) (and dummies and fakes and spies)
8. TDD
9. TDD
10. TDD
11. Refactoring
12. Refactoring
13. Refactoring
14. Queries & commands (a small digression)
15. Queries User
 repository Authenticator Session
16. Queries User
 repository Authenticator Session findUser("bob");
17. Queries User
 repository Authenticator Session [a User object]
18. Commands User
 repository Authenticator Session setUser(user);
19. Test doubles (stubs & mocks)
20. Stubbing a query Stub
 repository Authenticator Session findUser("bob");
21. A stub simply returns canned values
22. A stub simply returns canned values (which may be real value objects or other test doubles)
23. Mocking a command User
 repository Authenticator Mock
 Session setUser(user);
24. A mock verifies methods were called
25. Stub queries Mock commands
26. (and dummies and fakes and spies)
27. Outside-in design
28. Identify responsibilities
29. Identify responsibilities Does the class have a single responsibility?
30. Identify responsibilities Does the class have a single responsibility? Yes test drive behaviour as normal
31. Identify responsibilities Does the class have a single responsibility? Yes test drive behaviour as normal No identify collaborating roles (interfaces) specify interactions using test doubles
32. Implement collaborators
33. Implement collaborators For each role identified at the layer above…
34. Implement collaborators For each role identified at the layer above… Identify responsibilities Does the class have a single responsibility? Yes test drive behaviour as normal No identify collaborating roles (interfaces) specify interactions using test doubles
35. Rules*
36. Rules* A class can arrange collaborators or do work
37. Rules* A class can arrange collaborators or do work Stub queries; mock commands
38. Rules* A class can arrange collaborators or do work Stub queries; mock commands Doubles can return value objects or other doubles (but not objects with behaviour)
39. Rules* A class can arrange collaborators or do work Stub queries; mock commands Doubles can return value objects or other doubles (but not objects with behaviour) Don’t stub or mock value objects or primitives
40. Rules* A class can arrange collaborators or do work Stub queries; mock commands Doubles can return value objects or other doubles (but not objects with behaviour) Don’t stub or mock value objects or primitives Don’t stub or mock the object under test
41. Rules* A class can arrange collaborators or do work Stub queries; mock commands Doubles can return value objects or other doubles (but not objects with behaviour) Don’t stub or mock value objects or primitives Don’t stub or mock the object under test
42. Rules* A class can arrange collaborators or do work Stub queries; mock commands Doubles can return value objects or other doubles (but not objects with behaviour) Don’t stub or mock value objects or primitives Don’t stub or mock the object under test *more what you’d call ‘guidelines’ than actual rules
43. Show me the code!
44. Java frameworks
45. Java frameworks EasyMock
46. Java frameworks EasyMock JMock
47. Java frameworks EasyMock JMock Mockito
48. Java frameworks EasyMock JMock Mockito JMockit
49. Java frameworks EasyMock JMock Mockito JMockit PowerMock
50. Java frameworks EasyMock JMock Mockito JMockit PowerMock
51. Our earlier example Stub
 repository Authenticator setUser(user); Mock
 Session findUser("bob");
52. public class Authenticator { public Authenticator(final Repository repository) { } public void authenticate(String username, Session session) { } }
53. public class Authenticator { public Authenticator(final Repository repository) { } public void authenticate(String username, Session session) { } } public interface Repository { User findUser(String username); }
54. public class Authenticator { public Authenticator(final Repository repository) { } public void authenticate(String username, Session session) { } } public interface Repository { User findUser(String username); } public interface Session { void setUser(User user); }
55. public class Authenticator { public Authenticator(final Repository repository) { } public void authenticate(String username, Session session) { } } public interface Repository { User findUser(String username); } public interface Session { void setUser(User user); } public class User { }
56. import org.junit.Test; import static org.easymock.EasyMock.*; public class AuthenticatorTest { @Test public void testAuthenticate() { User user = new User(); Repository stubRepository = createMock(Repository.class); expect(stubRepository.findUser("bob")).andStubReturn(user); replay(stubRepository); Session mockSession = createMock(Session.class); mockSession.setUser(user); replay(mockSession); Authenticator authenticator = new Authenticator(stubRepository); authenticator.authenticate("bob", mockSession); verify(mockSession); } }
57. import org.junit.Test; import static org.easymock.EasyMock.*; public class AuthenticatorTest { @Test public void testAuthenticate() { User user = new User(); Repository stubRepository = createMock(Repository.class); expect(stubRepository.findUser("bob")).andStubReturn(user); replay(stubRepository); Session mockSession = createMock(Session.class); mockSession.setUser(user); replay(mockSession); Authenticator authenticator = new Authenticator(stubRepository); authenticator.authenticate("bob", mockSession); verify(mockSession); } }
58. import org.junit.Test; import static org.easymock.EasyMock.*; public class AuthenticatorTest { @Test public void testAuthenticate() { User user = new User(); Repository stubRepository = createMock(Repository.class); expect(stubRepository.findUser("bob")).andStubReturn(user); replay(stubRepository); Session mockSession = createMock(Session.class); mockSession.setUser(user); replay(mockSession); Authenticator authenticator = new Authenticator(stubRepository); authenticator.authenticate("bob", mockSession); verify(mockSession); } }
59. import org.junit.Test; import static org.easymock.EasyMock.*; public class AuthenticatorTest { @Test public void testAuthenticate() { User user = new User(); Repository stubRepository = createMock(Repository.class); expect(stubRepository.findUser("bob")).andStubReturn(user); replay(stubRepository); Session mockSession = createMock(Session.class); mockSession.setUser(user); replay(mockSession); Authenticator authenticator = new Authenticator(stubRepository); authenticator.authenticate("bob", mockSession); verify(mockSession); } }
60. import org.junit.Test; import static org.easymock.EasyMock.*; public class AuthenticatorTest { @Test public void testAuthenticate() { User user = new User(); Repository stubRepository = createMock(Repository.class); expect(stubRepository.findUser("bob")).andStubReturn(user); replay(stubRepository); Session mockSession = createMock(Session.class); mockSession.setUser(user); replay(mockSession); Authenticator authenticator = new Authenticator(stubRepository); authenticator.authenticate("bob", mockSession); verify(mockSession); } }
61. import org.junit.Test; import static org.easymock.EasyMock.*; public class AuthenticatorTest { @Test public void testAuthenticate() { User user = new User(); Repository stubRepository = createMock(Repository.class); expect(stubRepository.findUser("bob")).andStubReturn(user); replay(stubRepository); Session mockSession = createMock(Session.class); mockSession.setUser(user); replay(mockSession); Authenticator authenticator = new Authenticator(stubRepository); authenticator.authenticate("bob", mockSession); verify(mockSession); } }
62. import org.junit.Test; import static org.easymock.EasyMock.*; public class AuthenticatorTest { @Test public void testAuthenticate() { User user = new User(); Repository stubRepository = createMock(Repository.class); expect(stubRepository.findUser("bob")).andStubReturn(user); replay(stubRepository); Session mockSession = createMock(Session.class); mockSession.setUser(user); replay(mockSession); Authenticator authenticator = new Authenticator(stubRepository); authenticator.authenticate("bob", mockSession); verify(mockSession); } }
63. import org.junit.Test; import static org.easymock.EasyMock.*; public class AuthenticatorTest { @Test public void testAuthenticate() { User user = new User(); Repository stubRepository = createMock(Repository.class); expect(stubRepository.findUser("bob")).andStubReturn(user); replay(stubRepository); Session mockSession = createMock(Session.class); mockSession.setUser(user); replay(mockSession); Authenticator authenticator = new Authenticator(stubRepository); authenticator.authenticate("bob", mockSession); verify(mockSession); } }
64. JUnit version 4.11 .E Time: 0.045 There was 1 failure: 1) testAuthenticate(AuthenticatorTest) java.lang.AssertionError: Expectation failure on verify: Session.setUser(User@27f8302d): expected: 1, actual: 0 at org.easymock.internal.MocksControl.verify (MocksControl.java:226) ... FAILURES!!! Tests run: 1, Failures: 1
65. JUnit version 4.11 .E Time: 0.045 There was 1 failure: 1) testAuthenticate(AuthenticatorTest) java.lang.AssertionError: Expectation failure on verify: Session.setUser(User@27f8302d): expected: 1, actual: 0 at org.easymock.internal.MocksControl.verify (MocksControl.java:226) ... FAILURES!!! Tests run: 1, Failures: 1
66. public class Authenticator { private Repository repository; public Authenticator(final Repository repository) { this.repository = repository; } public void authenticate(String username, Session session) { User user = repository.findUser(username); session.setUser(user); } }
67. JUnit version 4.11 . Time: 0.204 OK (1 test)
68. A stub simply returns canned values
69. A stub simply returns canned values A mock verifies methods were called
70. Stub queries Mock commands
71. Acceptance test tools
72. Behaviour-driven development Executable examples Customer Red Refactor Green Release
73. Behaviour-driven development Executable examples Customer Red Refactor Green Release
74. package com.example.calculator; import static org.junit.Assert.*; import org.junit.*; import com.example.Calculator; public class CalculatorTests { private Calculator calc; @Before public void SetUp() { calc = new Calculator(); } @Test public void testAddition() { calc.push("4"); calc.push("+"); calc.push("5"); assertEquals("9", calc.value()); } }
75. Feature: Basic Arithmetic Background: A Calculator Given a calculator I just turned on Scenario: Addition When I add 4 and 5 Then the result is 9 Scenario: Subtraction When I subtract 4 from 10 Then the result is 6
76. public class CalculatorStepdefs { private Calculator calc; @Given("^a calculator I just turned on$") public void a_calculator_I_just_turned_on() { calc = new Calculator(); } @When("^I add (\\d+) and (\\d+)$") public void adding(int arg1, int arg2) { calc.push(arg1); calc.push("+"); calc.push(arg2); } @Then("^the result is (\\d+)$") public void the_result_is(double expected) { assertEquals(expected, calc.value()); } }
77. public class CalculatorStepdefs { private Calculator calc; @Given("^a calculator I just turned on$") public void a_calculator_I_just_turned_on() { calc = new Calculator(); } @When("^I add (\\d+) and (\\d+)$") public void adding(int arg1, int arg2) { calc.push(arg1); calc.push("+"); calc.push(arg2); } @Then("^the result is (\\d+)$") public void the_result_is(double expected) { assertEquals(expected, calc.value()); } }
78. public class CalculatorStepdefs { private Calculator calc; @Given("^a calculator I just turned on$") public void a_calculator_I_just_turned_on() { calc = new Calculator(); } @When("^I add (\\d+) and (\\d+)$") public void adding(int arg1, int arg2) { calc.push(arg1); calc.push("+"); calc.push(arg2); } @Then("^the result is (\\d+)$") public void the_result_is(double expected) { assertEquals(expected, calc.value()); } }
79. public class CalculatorStepdefs { private Calculator calc; @Given("^a calculator I just turned on$") public void a_calculator_I_just_turned_on() { calc = new Calculator(); } @When("^I add (\\d+) and (\\d+)$") public void adding(int arg1, int arg2) { calc.push(arg1); calc.push("+"); calc.push(arg2); } @Then("^the result is (\\d+)$") public void the_result_is(double expected) { assertEquals(expected, calc.value()); } }
80. public class CalculatorStepdefs { private Calculator calc; @Given("^a calculator I just turned on$") public void a_calculator_I_just_turned_on() { calc = new Calculator(); } @When("^I add (\\d+) and (\\d+)$") public void adding(int arg1, int arg2) { calc.push(arg1); calc.push("+"); calc.push(arg2); } @Then("^the result is (\\d+)$") public void the_result_is(double expected) { assertEquals(expected, calc.value()); } }
81. public class CalculatorStepdefs { private Calculator calc; @Given("^a calculator I just turned on$") public void a_calculator_I_just_turned_on() { calc = new Calculator(); } @When("^I add (\\d+) and (\\d+)$") public void adding(int arg1, int arg2) { calc.push(arg1); calc.push("+"); calc.push(arg2); } @Then("^the result is (\\d+)$") public void the_result_is(double expected) { assertEquals(expected, calc.value()); } }
82. Testing web apps
84. Feature: Finding train times Scenario: Search for a single journey Given it is 17.30 on 25/10/2014 When I want to travel from Ipswich to Liverpool Street And I want to travel on 27/10/2014 And I search for trains Then the first train should leave at 17:43 public class TrainTimesStepdefs { @When("^I want to travel from (.+) to (.+)$”) public void chooseStations(String from, String to) { WebDriver driver = new FirefoxDriver(); driver.get(“http://www.nationalrail.co.uk/"); element = driver.findElement(By.name("txtFrom")); element.sendKeys(from); element = driver.findElement(By.name("txtTo")); element.sendKeys(to); } }
85. Feature: Finding train times Scenario: Search for a single journey Given it is 17.30 on 25/10/2014 When I want to travel from Ipswich to Liverpool Street And I want to travel on 27/10/2014 And I search for trains Then the first train should leave at 17:43 public class TrainTimesStepdefs { @When("^I want to travel from (.+) to (.+)$") public void chooseStations(String from, String to) { WebDriver driver = new FirefoxDriver(); driver.get("http://www.nationalrail.co.uk/"); element = driver.findElement(By.name("txtFrom")); element.sendKeys(from); element = driver.findElement(By.name("txtTo")); element.sendKeys(to); } }
86. Feature: Finding train times Scenario: Search for a single journey Given it is 17.30 on 25/10/2014 When I want to travel from Ipswich to Liverpool Street And I want to travel on 27/10/2014 And I search for trains Then the first train should leave at 17:43 public class TrainTimesStepdefs { @When("^I want to travel from (.+) to (.+)$") public void chooseStations(String from, String to) { WebDriver driver = new FirefoxDriver(); driver.get("http://www.nationalrail.co.uk/"); element = driver.findElement(By.name("txtFrom")); element.sendKeys(from); element = driver.findElement(By.name("txtTo")); element.sendKeys(to); } }
87. Feature: Finding train times Scenario: Search for a single journey Given it is 17.30 on 25/10/2014 When I want to travel from Ipswich to Liverpool Street And I want to travel on 27/10/2014 And I search for trains Then the first train should leave at 17:43 public class TrainTimesStepdefs { @When("^I want to travel from (.+) to (.+)$") public void chooseStations(String from, String to) { WebDriver driver = new FirefoxDriver(); driver.get("http://www.nationalrail.co.uk/"); element = driver.findElement(By.name("txtFrom")); element.sendKeys(from); element = driver.findElement(By.name("txtTo")); element.sendKeys(to); } }