iOS Unit Testing Workshop

Transcript

1. Unit Testing for iOS $> git clone --recursive https://github.com/moredip/run2bart-iOS.git $>

   cd run2bart-iOS $> open Run2Bart/Run2Bart.xcworkspace you should have already done this:

2. me me me Pete Hodgson Consultant at ThoughtWorks @ph1 blog.thepete.net

3. tell me about yourself experience with iOS? experience with automated

   testing? experience testing with iOS?

4. goals for the workshop hands on experience good testing practices

   overview of all the major moving parts of Kiwi introduction to the advanced stuff

5. some theory, some hands-on (with pairing!) workshop format

6. interrupt, raise your hand, ask questions Please

7. why should you care? Unit Testing

8. None
9. None
10. None

11. 1. write code 2. submit stack of cards 3. wait

    (probably overnight) 4. find out if your program worked

12. Feedback

13. write it check it

14. feedback

15. 24 hrs punchcards

16. 60 mins big ol’ C++ program

17. http://xkcd.com/303/

18. 10 secs an iOS app

19. what’s next?

20. of feedback speed

21. of feedback quality

22. syntax vs. semantics

23. does it compile? static analysis unit testing

24. unit testing means better feedback

25. what is a unit test?

26. what is NOT unit test?

27. types of automated testing

28. Your App End User Backend Services

29. Unit Test Your App End User Backend Services

30. Integration Test Your App End User Backend Services

31. Acceptance Test Your App End User Backend Services

32. Acceptance Test Your App End User Backend Services The App

33. Acceptance Unit Integration

34. “my first unit test” with kiwi

35. what is kiwi? open-source tool builds on top of stock

    XCode tooling adds nicer ways of organizing tests adds nicer ways to make assertions adds ability to mock/stub

36. setting up a project to use Kiwi

37. Guide: Up and Running with Kiwi https://github.com/allending/Kiwi/wiki

38. CocoaPods makes this a lot easier https://github.com/CocoaPods/CocoaPods

39. what is a unit test?

40. x+1 12 13

41. system under test in out

42. #import "Kiwi.h" SPEC_BEGIN(MyFirstSpec) describe(@"Basic Arithmetic", ^{ it(@"can increment 12",^{ [[theValue(12+1)

    should] equal:theValue(13)]; }); }); SPEC_END myFirstSpec.m

43. Hands-on: writing our first test

44. $> git checkout sl-2 $> git clean -dxf 1: Close

    XCode 2: 3: Open Run2Bart.xcworkspace

45. #import "Kiwi.h" SPEC_BEGIN(MyFirstSpec) describe(@"Basic Arithmetic", ^{ it(@"can increment 12",^{ [[theValue(12+1)

    should] equal:theValue(13)]; }); }); SPEC_END ExampleSpec.m

46. 12+1 does equal 13 does 12*2 equal 24?

47. #import "Kiwi.h" SPEC_BEGIN(MyFirstSpec) describe(@"Basic Arithmetic", ^{ it(@"can increment 12",^{ [[theValue(12+1)

    should] equal:theValue(13)]; }); }); SPEC_END ExampleSpec.m

48. testing ‘real’ app code parsing JSON

49. Introducing: Run2Bart

50. parsing JSON

51. @implementation Station + (NSArray *)loadStations:(NSArray *)rawStations { NSMutableArray *stations =

    [NSMutableArray array]; for(NSDictionary *rawStation in rawStations){ Station *station = [[Station alloc] initWithName:rawStation[@"name"] abbr:rawStation[@"abbr"]]; [stations addObject:station]; } return stations; } - (id)initWithName:(NSString *)name abbr:(NSString *)abbr { self = [super init]; if (self) { _name = [name copy]; ! ! _abbr = [abbr copy]; } return self; } @end Station.m

52. system under test in out

53. [ { “name”:”foo”, ... }, {...} ] Station loadStations

54. describe(@"Station", ^{ it(@"loads from JSON correctly",^{ NSArray *rawStations = @[

    @{@"abbr":@"s1",@"name":@"station one"}, @{@"abbr":@"s2",@"name":@"station two"}, ]; NSArray *stations = [Station loadStations:rawStations]; [[theValue(stations.count) should] equal:theValue(2)]; [[[stations[0] abbr] should] equal:@"s1"]; [[[stations[0] name] should] equal:@"station one"]; [[[stations[1] abbr] should] equal:@"s2"]; [[[stations[1] name] should] equal:@"station two"]; }); }); StationSpec.m

55. Arrange, Act, Assert

56. describe(@"Station", ^{ it(@"loads from JSON correctly",^{ NSArray *rawStations = @[

    @{@"abbr":@"s1",@"name":@"station one"}, @{@"abbr":@"s2",@"name":@"station two"}, ]; NSArray *stations = [Station loadStations:rawStations]; [[theValue(stations.count) should] equal:theValue(2)]; [[[stations[0] abbr] should] equal:@"s1"]; [[[stations[0] name] should] equal:@"station one"]; [[[stations[1] abbr] should] equal:@"s2"]; [[[stations[1] name] should] equal:@"station two"]; }); }); arrange

57. describe(@"Station", ^{ it(@"loads from JSON correctly",^{ NSArray *rawStations = @[

    @{@"abbr":@"s1",@"name":@"station one"}, @{@"abbr":@"s2",@"name":@"station two"}, ]; NSArray *stations = [Station loadStations:rawStations]; [[theValue(stations.count) should] equal:theValue(2)]; [[[stations[0] abbr] should] equal:@"s1"]; [[[stations[0] name] should] equal:@"station one"]; [[[stations[1] abbr] should] equal:@"s2"]; [[[stations[1] name] should] equal:@"station two"]; }); }); act

58. describe(@"Station", ^{ it(@"loads from JSON correctly",^{ NSArray *rawStations = @[

    @{@"abbr":@"s1",@"name":@"station one"}, @{@"abbr":@"s2",@"name":@"station two"}, ]; NSArray *stations = [Station loadStations:rawStations]; [[theValue(stations.count) should] equal:theValue(2)]; [[[stations[0] abbr] should] equal:@"s1"]; [[[stations[0] name] should] equal:@"station one"]; [[[stations[1] abbr] should] equal:@"s2"]; [[[stations[1] name] should] equal:@"station two"]; }); }); assert

59. describe(@"Station", ^{ it(@"loads from JSON correctly",^{ ////////////////// // Arrange NSArray

    *rawStations = @[ @{@"abbr":@"s1",@"name":@"station one"}, @{@"abbr":@"s2",@"name":@"station two"}, ]; ////////////////// // Act NSArray *stations = [Station loadStations:rawStations]; ////////////////// // Assert [[theValue(stations.count) should] equal:theValue(2)]; [[[stations[0] abbr] should] equal:@"s1"]; [[[stations[0] name] should] equal:@"station one"]; [[[stations[1] abbr] should] equal:@"s2"]; [[[stations[1] name] should] equal:@"station two"]; }); });

60. Given, When, Then

61. describe(@"Station", ^{ it(@"loads from JSON correctly",^{ ////////////////// // Given NSArray

    *rawStations = @[ @{@"abbr":@"s1",@"name":@"station one"}, @{@"abbr":@"s2",@"name":@"station two"}, ]; ////////////////// // When NSArray *stations = [Station loadStations:rawStations]; ////////////////// // Then [[theValue(stations.count) should] equal:theValue(2)]; [[[stations[0] abbr] should] equal:@"s1"]; [[[stations[0] name] should] equal:@"station one"]; [[[stations[1] abbr] should] equal:@"s2"]; [[[stations[1] name] should] equal:@"station two"]; }); });

62. another simple test displaying estimated departures

63. 5 “5 mins” etdToDisplay

64. #import "Kiwi.h" #import "UpcomingDeparture.h" SPEC_BEGIN(UpcomingDepartureSpec) describe(@"[UpcomingDeparture etdToDisplay]", ^{ it(@"is correct

    for an etd of 5",^{ UpcomingDeparture *upcomingDeparture = [[UpcomingDeparture alloc] initWithDestinationName:@"blah" etd:@(5)]; [[[upcomingDeparture etdToDisplay] should] equal:@"5 mins"]; }); }); SPEC_END UpcomingDepartureSpec.m

65. - (NSString *) etdToDisplay{ return [NSString stringWithFormat:@"%@ mins", self.etdInMinutes]; }

    UpcomingDeparture.m

66. 5 “5 mins” etdToDisplay

67. etdToDisplay 1 “1 min” 5 “5 mins”

68. etdToDisplay 0 “now” 5 “5 mins” 1 “1 min”

69. Let’s do some TDD!

70. describe(@"[UpcomingDeparture etdToDisplay]", ^{ it(@"is correct for an etd of 5",^{

    UpcomingDeparture *upcomingDeparture = [[UpcomingDeparture alloc] initWithDestinationName:@"blah" etd:@(5)]; [[[upcomingDeparture etdToDisplay] should] equal:@"5 mins"]; }); it(@"is correct for an etd of 1",^{ UpcomingDeparture *upcomingDeparture = [[UpcomingDeparture alloc] initWithDestinationName:@"blah" etd:@(1)]; [[[upcomingDeparture etdToDisplay] should] equal:@"1 min"]; }); it(@"is correct for an etd of 0",^{ UpcomingDeparture *upcomingDeparture = [[UpcomingDeparture alloc] initWithDestinationName:@"blah" etd:@(0)]; [[[upcomingDeparture etdToDisplay] should] equal:@"now"]; }); }); UpcomingDepartureSpec.m

71. edge-cases made easier

72. ~ BREAK? ~

73. testing UIKit code

74. $> git checkout sl-3 $> git clean -dxf 1: Close

    XCode 2: 3: Open Run2Bart.xcworkspace

75. - (id)initForStation:(Station *)station { self = [super init]; if (self)

    { self.station = station; self.title = station.name; self.bartClient = [AppDelegate sharedInstance].bartClient; } return self; } UpcomingDeparturesViewController.m

76. SPEC_BEGIN(UpcomingDeparturesViewControllerSpec) describe( @"UpcomingDeparturesViewController ", ^{ it( @"has the station's name

    as the title", ^{ // Given Station *theStation = [[Station alloc] initWithName:@"station name" abbr:@"station-abbr"]; UpcomingDeparturesViewController *theDeparturesVC = [[UpcomingDeparturesViewController alloc] initForStation:theStation]; // Then [[theDeparturesVC.title should] equal:@"station name"]; }); // ... UpcomingDeparturesViewControllerSpec.m

77. UIKit code is still just code

78. testing UIKit code rendering UITableViewCells

79. - (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath { static NSString *CellIdentifier

    = @"Cell"; UpcomingDeparture *departure = [self.departures objectAtIndex:indexPath.row]; UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier]; if( !cell ) cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleValue1 reuseIdentifier:CellIdentifier]; cell.textLabel.font = [UIFont systemFontOfSize:18.0]; cell.detailTextLabel.font = [UIFont systemFontOfSize:24.0]; cell.textLabel.text = departure.destinationName; cell.detailTextLabel.text = departure.etdToDisplay; return cell; } UpcomingDeparturesViewController.m

80. describe(@"rendering departures", ^{ it( @"renders a table view cell for

    each departure", ^{ // Given UITableView *ignoredTableView = nil; Station *someStation = [[Station alloc] initWithName:@"station name" abbr:@"station-abbr"]; UpcomingDeparturesViewController *departuresVC = [[UpcomingDeparturesViewController alloc] initForStation:someStation]; NSArray *departures = @[ [[UpcomingDeparture alloc] initWithDestinationName:@"dest 1" etd:@(0)], [[UpcomingDeparture alloc] initWithDestinationName:@"dest 2" etd:@(1)], [[UpcomingDeparture alloc] initWithDestinationName:@"dest 3" etd:@(2)] ]; departuresVC.departures = departures; // When NSInteger numSections = [departuresVC numberOfSectionsInTableView:ignoredTableView]; NSInteger numRows = [departuresVC tableView:ignoredTableView numberOfRowsInSection:0]; // Then [[theValue(numSections) should] equal:theValue(1)]; [[theValue(numRows) should] equal:theValue(3)]; }); }); UpcomingDeparturesViewControllerSpec.m

81. your turn test that: table view cells have the right

    data

82. hints [departureVC tableView:cellForRowAtIndexPath:] tableViewCell.textLabel.text tableViewCell.detailTextLabel.text BREAK after this

83. ~ BREAK? ~

84. test doubles (mocks/stubs)

85. $> git checkout sl-4 $> git clean -dxf 1: Close

    XCode 2: 3: Open Run2Bart.xcworkspace

86. UpcomingDeparturesViewController.m - (void)viewWillAppear:(BOOL)animated{ [self refreshUpcomingDepartures]; } - (void) refreshUpcomingDepartures{ [self.refreshControl

    beginRefreshing]; [self.bartClient fetchUpcomingDeparturesForStation:self.station success:^(NSArray *departures) { [self.refreshControl endRefreshing]; self.departures = departures; [self.tableView reloadData]; } failure:^(NSError *error) { [self.refreshControl endRefreshing]; }]; }

87. Dependencies in Unit Tests

88. API UI Business Logic

89. API UI Business Logic SUT

90. API UI Business Logic SUT

91. API UI Business Logic SUT

92. API UI Business Logic SUT TD TD

93. SUT TD TD

94. API UI Business Logic SUT

95. API UI Business Logic SUT View Controller

96. API UI Business Logic SUT BartClient View Controller

97. API UI Business Logic SUT TD

98. API UI Business Logic SUT TD View Controller

99. API UI Business Logic SUT TD Spy BartClient View Controller

100. - (void)viewWillAppear:(BOOL)animated{ [self refreshUpcomingDepartures]; } - (void) refreshUpcomingDepartures{ [self.refreshControl beginRefreshing];

     [self.bartClient fetchUpcomingDeparturesForStation:self.station success:^(NSArray *departures) { [self.refreshControl endRefreshing]; self.departures = departures; [self.tableView reloadData]; } failure:^(NSError *error) { [self.refreshControl endRefreshing]; }]; } UpcomingDeparturesViewController.m

101. @interface SpyBartClient : NSObject<BartClient>{ BOOL _fetchWasCalled; } @end @implementation SpyBartClient

     - (id)init { self = [super init]; if (self) { _fetchWasCalled = NO; } return self; } - (void)fetchUpcomingDeparturesForStation:(Station *)station success:(FetchSuccessBlock)success failure:(FetchFailureBlock)failure{ _fetchWasCalled = YES; } - (BOOL)fetchUpcomingDeparturesWasCalled{ return _fetchWasCalled; } @end UpcomingDeparturesViewControllerSpec.m

102. describe(@"the VC's view appearing", ^{ it( @"asks the api client

     to load the upcoming departures", ^{ SpyBartClient *testDoubleBartClient = [[SpyBartClient alloc] init]; departuresVC.bartClient = testDoubleBartClient; [departuresVC viewWillAppear:YES]; [[theValue([testDoubleBartClient fetchUpcomingDeparturesWasCalled]) should] beTrue]; }); }); UpcomingDeparturesViewControllerSpec.m

103. API UI Business Logic SUT TD Spy BartClient View Controller

104. from hand-rolled to dynamic

105. @interface SpyBartClient : NSObject<BartClient>{ BOOL _fetchWasCalled; } @end @implementation SpyBartClient

     - (id)init { self = [super init]; if (self) { _fetchWasCalled = NO; } return self; } - (void)fetchUpcomingDeparturesForStation:(Station *)station success:(FetchSuccessBlock)success failure:(FetchFailureBlock)failure{ _fetchWasCalled = YES; } - (BOOL)fetchUpcomingDeparturesWasCalled{ return _fetchWasCalled; } @end UpcomingDeparturesViewControllerSpec.m

106. UpcomingDeparturesViewControllerSpec.m id mockBartClient = [KWMock mockForProtocol:@protocol(BartClient)];

107. UpcomingDeparturesViewControllerSpec.m it( @"asks the api client to load the upcoming

     departures", ^{ id mockBartClient = [KWMock mockForProtocol:@protocol(BartClient)]; departuresVC.bartClient = mockBartClient; [[mockBartClient should] receive:@selector(fetchUpcomingDeparturesForStation:success:failure:) andReturn:nil]; [departuresVC viewWillAppear:YES]; });

108. it( @"asks the api client to load the upcoming departures",

     ^{ id mockBartClient = [KWMock mockForProtocol:@protocol(BartClient)]; departuresVC.bartClient = mockBartClient; [[mockBartClient should] receive:@selector(fetchUpcomingDeparturesForStation:success:failure:) andReturn:nil]; [departuresVC viewWillAppear:YES]; }); it( @"asks the api client to load the upcoming departures", ^{ SpyBartClient *testDoubleBartClient = [[SpyBartClient alloc] init]; departuresVC.bartClient = testDoubleBartClient; [departuresVC viewWillAppear:YES]; [[theValue([testDoubleBartClient fetchUpcomingDeparturesWasCalled] should] beTrue]; }); hand-rolled dynamic

109. verifying what has been sent to a test double

110. - (void)viewWillAppear:(BOOL)animated{ [self refreshUpcomingDepartures]; } - (void) refreshUpcomingDepartures{ [self.refreshControl beginRefreshing];

     [self.bartClient fetchUpcomingDeparturesForStation:self.station success:^(NSArray *departures) { [self.refreshControl endRefreshing]; self.departures = departures; [self.tableView reloadData]; } failure:^(NSError *error) { [self.refreshControl endRefreshing]; }]; } UpcomingDeparturesViewController.m

111. UpcomingDeparturesViewControllerSpec.m it( @"asks the api client to load the upcoming

     departures for the right station", ^{ id mockBartClient = [KWMock mockForProtocol:@protocol(BartClient)]; departuresVC.bartClient = mockBartClient; [[[mockBartClient should] receive] fetchUpcomingDeparturesForStation:station success:any() failure:any()]; [departuresVC viewWillAppear:YES]; });

112. another way to think about mocks/stubs

113. system under test in out

114. D e p e n d e n c y

     system under test indirect output indirect input direct input direct output T e s t

115. API UI Business Logic SUT BartClient View Controller

116. API UI Business Logic SUT

117. usiness ogic SUT SUT TD Test

118. D e p e n d e n c y

     system under test indirect output indirect input direct input direct output T e s t values passed to dependency via method call values returned from call to dependency

119. ~ BREAK? ~

120. DRYing up your test code

121. $> git checkout sl-3 $> git clean -dxf 1: Close

     XCode 2: 3: Open Run2Bart.xcworkspace

122. Don’t Repeat Yourself

123. describe( @"UpcomingDeparturesViewController ", ^{ it( @"has the station's name as

     the title", ^{ // Given Station *theStation = [[Station alloc] initWithName:@"station name" abbr:@"station-abbr"]; UpcomingDeparturesViewController *theDeparturesVC = [[UpcomingDeparturesViewController alloc] initForStation:theStation]; // Then [[theDeparturesVC.title should] equal:@"station name"]; }); // ... UpcomingDeparturesViewControllerSpec.m

124. describe( @"UpcomingDeparturesViewController ", ^{ it( @"has the station's name as

     the title", ^{ // Given Station *theStation = [[Station alloc] initWithName:@"station name" abbr:@"station-abbr"]; UpcomingDeparturesViewController *theDeparturesVC = [[UpcomingDeparturesViewController alloc] initForStation:theStation]; // Then [[theDeparturesVC.title should] equal:@"station name"]; }); // ... UpcomingDeparturesViewControllerSpec.m

125. describe( @"UpcomingDeparturesViewController ", ^{ __block Station *station; __block UpcomingDeparturesViewController *departuresVC;

     beforeEach(^{ station = [[Station alloc] initWithName:@"station name" abbr:@"station-abbr"]; departuresVC = [[UpcomingDeparturesViewController alloc] initForStation:station]; }) it( @"has the station's name as the title", ^{ // Then [[departuresVC.title should] equal:station.name]; }); // ... UpcomingDeparturesViewControllerSpec.m

126. your turn: DRY it up UpcomingDeparturesViewControllerSpec.m introduce a beforeEach block

     change tests in the file to take advantage of it

127. describe( @"UpcomingDeparturesViewController ", ^{ __block Station *station; __block UpcomingDeparturesViewController *departuresVC;

     beforeEach(^{ station = [[Station alloc] initWithName:@"station name" abbr:@"station-abbr"]; departuresVC = [[UpcomingDeparturesViewController alloc] initForStation:station]; }) it( @"has the station's name as the title", ^{ // Then [[departuresVC.title should] equal:station.name]; }); // ... UpcomingDeparturesViewControllerSpec.m

128. how unit-testing influences design

129. None

130. testable code is also loosely coupled and highly coherent

131. most of your code shouldn’t be UIKit code

132. Test-Driven Development

133. Test-Driven Design

134. TDD works best with fast tests

135. extra stuff - xctool - specta/expecta