book

Test Driven Development: By Example

by Kent Beck

November 2002

Intermediate to advanced

240 pages

5h 9m

English

Addison-Wesley Professional

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Courage

What’s Next?MetaphorJUnit UsageCode MetricsProcessTest QualityOne Last Review
Test (noun)Isolated TestTest ListTest FirstAssert FirstTest DataEvident Data
One Step TestStarter TestExplanation TestLearning Test1Another TestRegression TestBreakDo OverCheap Desk, Nice Chair
Child TestMock ObjectSelf ShuntLog StringCrash Test DummyBroken TestClean Check-in
Fake It (’Til You Make It)TriangulateObvious ImplementationOne to Many
AssertionFixtureExternal FixtureTest MethodException TestAll Tests
CommandValue ObjectNull ObjectTemplate MethodPluggable ObjectPluggable Selector3Factory MethodImposterCompositeCollecting ParameterSingleton
Reconcile DifferencesIsolate ChangeMigrate DataExtract MethodInline MethodExtract InterfaceMove MethodMethod ObjectAdd ParameterMethod Parameter to Constructor Parameter
How large should your steps be?What don’t you have to test?How do you know if you have good tests?How does TDD lead to frameworks?How much feedback do you need?When should you delete tests?How do the programming language and environment influence TDD?Can you test drive enormous systems?Can you drive development with application-level tests?How do you switch to TDD midstream?Who is TDD intended for?Is TDD sensitive to initial conditions?How does TDD relate to patterns?Why does TDD work?What’s with the name?How does TDD relate to the practices of Extreme Programming?Darach’s Challenge
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Content preview from Test Driven Development: By Example

Chapter 29 xUnit Patterns

These are patterns for using one of the xUnit family of testing frameworks.

Assertion

How do you check that tests worked correctly? Write boolean expressions that automate your judgment about whether the code worked.

If we are going to make the tests fully automated, then every bit of human judgment has to be taken out of the evaluation of the results. We need to push a button and make all of the decisions necessary to verify the correct working of the code that the computer runs. This suggests the following.

The decisions have to be boolean—True generally means everything is okay, and false means something unexpected happened.
The state of the booleans have to be checked by computer, by calling some variant of an ...