ADVANCED TDD Diego Aguiar Beltrán @MolloKhan

➢ Developer at SymfonyCasts ➢ Hiking ➢ Gaming (Warcraft FTW!) ➢ Tepic, Mexico Diego Aguiar Beltrán @MolloKhan

Main Topics ➢ What TDD Really is ➢ Useful TDD Techniques ➢ What “Getting Stuck” means ➢ When Not to TDD

What is TDD? ➢ Programming Methodology ➢ It’s Composed of 3 Laws ➢ Tests Always Go First ➢ Red, Green, Refactor cycle

TDD is more like a discipline

➢ Practice, practice, practice… ➢ Train Your Mind ➢ Tests Go First

A bit of History… ➢ Kent Beck inventor of TDD ➢ Invented In the late 1990’s ➢ As a way to write better quality code

TDD Techniques ➢ Fake it till you make it ➢ Triangulation ➢ Assert First

Fake it till you make it

Name Inverter Example “Diego Aguiar” → “Aguiar, Diego” Fake it till you make it

Where to start? Fake it till you make it

Fake it till you make it public function testNullCase() { $name = null; $invertedName = $this->nameInverter ->invert($name); self::assertEquals('', $invertedName); } public function invert($name) { // Forcing test to pass return ‘’; } TEST CODE PRODUCTION

public function invert($name) { return 'Diego'; } PRODUCTION Fake it till you make it public function testSingleName() { $name = 'Diego'; $invertedName = $this->nameInverter ->invert($name); self::assertEquals( 'Diego', $invertedName ); } TEST CODE

Fake it till you make it PRODUCTION public function invert($name) { if (!$name) { return ''; } return $name; }

Triangulation

Triangulation class NameInverterTest extends TestCase { public function testNullCase() { $invertedName = $this->nameInverter->invert(null); self::assertEquals('', $invertedName); } public function testSingleName() { $invertedName = $this->nameInverter->invert('Diego'); self::assertEquals('Diego', $invertedName); } }

Fake it till you make it & Triangulation The Best of Friends

Assert First

Assert First class NameInverterTest extends TestCase { public function testFullName() { $name = 'Diego Aguiar'; $invertedName = $this->nameInverter ->invert($name); self::assertEquals('Aguiar, Diego', $invertedName); } }

Getting Stuck

Why does it happen? ➢ It’s a symptom of a problem ➢ Production code is too specific ➢ You wrote the wrong test ➢ Aiming for the goal too fast

How to get Unstuck ➢ Step up and think for a simpler test ➢ Refactor hard-to-test code ➢ Write a list of use-cases ➢ Ignore testing for a moment

When Not to TDD ➢ Configuration ➢ Discovering ➢ Repository Queries

➢ TDD is more like a discipline ➢ There are techniques to get you unstuck ➢ TDD is a tool, not a rule Conclusion @MolloKhan

Happy TDD! @MolloKhan “One test a day keeps bugs away"

Z zero (or empty case) O one M many B boundaries I interfaces E exceptions BONUS!! https://i.ytimg.com/vi/0xRCYmbvfEs/maxresdefault.jpg

Happy TDD! @MolloKhan THANK YOU AGAIN!