(Unit) Testing ios Apps. Paweł Dudek

Transcription

1 (Unit) Testing ios Apps Paweł Dudek 1

2 Why do we want to write tests? 2

3 Reasons for testing Striving for better software Leads to better, more modularized codebase Faster development cycles Being confident about your code Less code to write Saved time 3

4 Common misconceptions 4

5 Common misconceptions It will take longer to write code or Time spent writing/refactoring tests is time lost It will take more time to modify existing system 5

6 Reasons for testing Striving for better software Leads to better, more modularized codebase Faster development cycles Being confident about your code Less code to write Saved time 6

7 Am I going to write poor software if I don t do tests? 7

8 Are unit tests an invaluable tool for writing great software? Heck yes. Am I going to produce a poor product if I can t unit test? Hell no. Jonathan Rasmusson 8

9 Now that we know that writing tests is a good idea... 9

10 How can we do it? 10

11 Warning You will feel confused You won t know how to start You will need help Conclusion: it s not easy to start 11

12 Tips Never think of tests as tests Think of a scenario, behavior, example Grab a mature project from github with tests included Find someone experienced and ask questions Program in pairs! 12

13 Get on with it! How can we test? 13

14 TDD Test Driven Development Red, Green, Refactor Write failing test first Fix it Refactor 14

15 BDD Behavior Driven Development 15

16 How does BDD differ from TDD? 16

17 BDD builds upon TDD by formalising the good habits of the best TDD practitioners. Matt Wynne, XP Evangelist 17

18 Good habits Work outside-in Use examples Use ubiquitous language 18

19 A little bit of terminology... 19

20 Terminology Mocking (mocks & stubs) Expecting Matching Faking 20

21 Testing in ios 21

22 Unit Tests 22

23 OCUnit Oldest Mac testing framework - officially supported by Apple since 2005 Integrated with XCode Built-in assertion macros 23

24 OCUnit Syntax All test classes inherit from SenTestCase All tests begin with test Setup and teardown method Everything else is ignored by testing framework Means you can use as additional setup methods! 24

25 OCUnit -(void)testfullname { Person *person = [Person person]; person.firstname person.secondname NSString *fullname = [person fullname]; NSString *expectedname Testowniczek"; STAssertTrue([fullName } 25

26 OCUnit vs XCTest 26

27 Behavior Tests 27

28 Kiwi and Cedar Nearly the same syntax Built-in stubs/mocks Built-in matchers 28

29 Kiwi and Cedar Syntax 29

30 SPEC_BEGIN(PersonSpec)! ^{ block Person *person;! beforeeach(^{ person = [[Person alloc] init]; person.firstname person.lastname Last Name"; });! describe(@"full name", ^{! block NSString *fullname;! beforeeach(^{ fullname = [person fullname]; });! it(@"should return the full name", ^{ expect(fullname).to(equal(@"mariusz Testowniczek")); }); }); });! SPEC_END 30

31 Example 31

32 Cedar Taptera Additions 32

33 The action block 33

34 The action block Syntax addition to previous blocks Executed after all beforeeach s for given example are run Really useful when chaining behavior tests 34

35 Describe beforeeach action Describe beforeeach action Describe beforeeach action it 35

36 Example 36

37 Helper libraries 37

38 Helper libraries Mocking: OCMock, OCMockito, LRMockey Expecting: Expecta Matching: OCHamcrest 38

39 Most the presented libraries offer similar functionality It all depends on syntax. 39

40 ios Testing Tips 40

41 Testing UI Layout Hard to maintain (as can change rapidly when GD goes on a rampage) Gives little value (quickly noticed by QA if something is off) 41

42 System Singletons [UIDevice currentdevice] [UIScreen mainscreen] Makes hard to test if accessed directly Nice candidate for putting in a property 42

43 UIViewController transitions Pushing new view controllers on nav controller stack or using transitions API Use helper class Tests - check if a given method was called on the helper class 43

44 Testing UIView animations Easiest way is to use the block-based API Helper class similar to transitions Tests - use fake to immediately call the animation block 44

45 Common caveats Don t set mocks on [UIViewController view] Avoid using categories to override system properties or existing behaviour Keychain and most of system objects are unavailable when tests are run from command line w/o simulator Don t test objects that are fakes or partial mocks 45

46 Things worth talking about but cut due to time limitations Frank / KIF - Application Tests Specta - yet another BDD style testing framework Dependency injection - Objection, Typhoon 46

47 Summary 47

48 Summary Testing is a great way to help developers Better codebase, faster iterations Invaluable for larger projects 48

49 Resources & Contact Code Examples github.com/paweldudek 49