tdd.md

TDD & JavaScript

Who?

Joscha Meyer Robert Kowalski

@OschenPoschen @robinson_k

(Wer macht unit tests und wer macht sie für javascript)

Why Jimdo <3 TDD?

What do we have?

Long living product - long living code

Fast changing requirements - fast changing code

Why Jimdo <3 TDD?

Less bugs

Speed up

Proven functioniality

What is TDD?

Unit Tests

Avoid regressions

Feedback (Continous, fast (F5, Clickpath))

What is TDD?

Red

Green

Refactor

Why Red Green Refactor

Describe the expected behaviour (name of test)

Think about result (implement expectation)

Green! (implement solution as fast as possible)

Make it DRY (refactor)

=> Validated tests

QUnit Test

<% code do %> test('firstLower lowers the first character', function() { var cc = new CC();

var result = cc.firstLower('FirstToLowerString');

strictEqual(result, 'firstToLowerString');

}); <% end %>

<% code do %> test('firstLower should keep lower first characters', function() { var cc = new CC();

var result = cc.firstLower('firstToLowerString');

strictEqual(result, 'firstToLowerString');

}); <% end %>

Stubbing and Mocking

Stubs: Fake Implentations (return values)

Mocks: Like Stubs, but with expectations

Stub: Example

Do's and don'ts

One assertion per test

Tests should be living docs

Test the communication with other Objects, don't test dependencies (external libraries, DOM)

If you cannot test it, fake it

Further "Reading"

• Test Driven Development: By Example - Kent Beck
• Test-Driven JavaScript Development - Christian Johansen
• http://www.cleancoders.com/ Screencasts
• Working Effectively with Legacy Code - Michael Feathers