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
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
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