Clean Unit Tests

The story about why unit tests matter.

Transcript

1. Чистые
   unit-тесты
   

   View Slide

2. What makes a clean test?
   Three things. Readability, readability, and readability.
   Robert C. Martin, «Clean Code»
   

   View Slide

3. #добришко
   

   View Slide

4. - (void)testLoadAlbums {
   NSError *err1 = [NSError errorWithDomain:@"" code:123 userInfo:nil];
   OCMStub([self.provider getAlbumsWithResultBlock:OCMOCK_ANY]).andDo(block);
   [self waitForExpectationsWithTimeout:1. handler:^(NSError *localError) {
   OCMVerify([self.provider getAlbumsWithResultBlock:OCMOCK_ANY]);
   }];
   }
   4
   

   View Slide

5. - (void)testLoadAlbums {
   NSError *err1 = [NSError errorWithDomain:@"" code:123 userInfo:nil];
   OCMStub([self.provider getAlbumsWithResultBlock:OCMOCK_ANY]).andDo(block);
   [self waitForExpectationsWithTimeout:1. handler:^(NSError *localError) {
   OCMVerify([self.provider getAlbumsWithResultBlock:OCMOCK_ANY]);
   }];
   }
   5
   

   View Slide

6. - (void)testLoadAlbums {
   NSError *err1 = [NSError errorWithDomain:@"" code:123 userInfo:nil];
   OCMStub([self.provider getAlbumsWithResultBlock:OCMOCK_ANY]).andDo(block);
   [self waitForExpectationsWithTimeout:1. handler:^(NSError *localError) {
   OCMVerify([self.provider getAlbumsWithResultBlock:OCMOCK_ANY]);
   }];
   }
   6
   

   View Slide

7. - (void)testLoadAlbums {
   NSError *err1 = [NSError errorWithDomain:@"" code:123 userInfo:nil];
   OCMStub([self.provider getAlbumsWithResultBlock:OCMOCK_ANY]).andDo(block);
   [self waitForExpectationsWithTimeout:1. handler:^(NSError *localError) {
   OCMVerify([self.provider getAlbumsWithResultBlock:OCMOCK_ANY]);
   }];
   }
   7
   

   View Slide

8. - (void)testDeletingMessages {
   NSMutableArray *messages = [NSMutableArray new];
   NSManagedObjectContext *ctx = [NSManagedObjectContext MR_contextForCurrentThread];
   [messages addObject:message];
   }
   XCTestExpectation *expectation = [self expectationWithDescription:
   [NSString stringWithFormat:@"%s", __PRETTY_FUNCTION__]];
   [self.service deleteMessages:messages withResultBlock:^(NSError *error) {
   [expectation fulfill];
   }];
   }
   8
   

   View Slide

9. - (void)testDeletingMessages {
   NSMutableArray *messages = [NSMutableArray new];
   NSManagedObjectContext *ctx = [NSManagedObjectContext MR_contextForCurrentThread];
   [messages addObject:message];
   }
   XCTestExpectation *expectation = [self expectationWithDescription:
   [NSString stringWithFormat:@"%s", __PRETTY_FUNCTION__]];
   [self.service deleteMessages:messages withResultBlock:^(NSError *error) {
   [expectation fulfill];
   }];
   }
   9
   

   View Slide

10. - (void)testDeletingMessages {
    NSMutableArray *messages = [NSMutableArray new];
    NSManagedObjectContext *ctx = [NSManagedObjectContext MR_contextForCurrentThread];
    [messages addObject:message];
    }
    XCTestExpectation *expectation = [self expectationWithDescription:
    [NSString stringWithFormat:@"%s", __PRETTY_FUNCTION__]];
    [self.service deleteMessages:messages withResultBlock:^(NSError *error) {
    [expectation fulfill];
    }];
    }
    10
    

    View Slide

11. - (void)testDeletingMessages {
    NSMutableArray *messages = [NSMutableArray new];
    NSManagedObjectContext *ctx = [NSManagedObjectContext MR_contextForCurrentThread];
    [messages addObject:message];
    }
    XCTestExpectation *expectation = [self expectationWithDescription:
    [NSString stringWithFormat:@"%s", __PRETTY_FUNCTION__]];
    [self.service deleteMessages:messages withResultBlock:^(NSError *error) {
    [expectation fulfill];
    }];
    }
    11
    

    View Slide

12. Зачем нужны чистые тесты
    Как писать чистые тесты
    Рефакторим тест
    12
    

    View Slide

13. Зачем нужны чистые тесты
    Как писать чистые тесты
    Рефакторим тест
    13
    

    View Slide

14. View Slide

15. /**
    @author Egor Tolstoy
    Метод возвращает закешированные результаты поиска для определенной
    поисковой строки
    @param searchTerm Поисковая строка
    @return Результаты поиска
    */
    - (NSArray *)obtainSearchResultsForSearchTerm:(NSString *)searchTerm;
    15
    

    View Slide

16. @implementation PeopleServiceImplementationTests
    - (void)testThatService {
    }
    - (void)testThatService {
    }
    - (void)testThatService {
    }
    - (void)testThatService {
    }
    @end
    16
    

    View Slide

17. @implementation PeopleServiceImplementationTests
    - (void)testThatService {
    }
    - (void)testThatService {
    }
    - (void)testThatService {
    }
    - (void)testThatService {
    }
    @end
    17
    

    View Slide

18. @implementation PeopleServiceImplementationTests
    - (void)testThatService {
    }
    - (void)testThatService {
    }
    - (void)testThatService {
    }
    - (void)testThatService {
    }
    @end
    18
    

    View Slide

19. @implementation PeopleServiceImplementationTests
    - (void)testThatService {
    }
    - (void)testThatService {
    }
    - (void)testThatService {
    }
    - (void)testThatService {
    }
    @end
    19
    

    View Slide

20. @implementation PeopleServiceImplementationTests
    - (void)testThatService {
    }
    - (void)testThatService {
    }
    - (void)testThatService {
    }
    - (void)testThatService {
    }
    @end
    20
    

    View Slide

21. /**
    Метод возвращает закешированные результаты поиска для определенной
    поисковой строки
    @param searchTerm Поисковая строка
    @return Результаты поиска
    */
    +
    ...ServiceReturnsCachedSearchResultsForCorrectQuery
    ...ServiceReturnsNilWhenNoResults
    ...ServiceReturnsNilForInvalidCharacters
    ...ServiceInterpretsDashesAsUnderscores
    21
    

    View Slide

22. Грязные тесты > Тяжело поддерживать >
    Удаление тестов > Падает качество проекта
    22
    

    View Slide

23. Грязные тесты > Тяжело поддерживать >
    Удаление тестов > Падает качество проекта
    23
    

    View Slide

24. Грязные тесты > Тяжело поддерживать >
    Удаление тестов > Падает качество проекта
    24
    

    View Slide

25. Грязные тесты > Тяжело поддерживать >
    Удаление тестов > Падает качество проекта
    25
    

    View Slide

26. Зачем нужны чистые тесты
    Как писать чистые тесты
    Рефакторим тест
    26
    

    View Slide

27. Чистый тест
    предметно-ориентированный язык
    без лишнего контекста
    тестируется одно поведение системы
    27
    

    View Slide

28. Предметно-ориентированный язык
    Хорошо
    XCTAssertEqualObjects(testAlbumError, expectedError);
    - (void)testThatServiceReturnsNilWhenNoResults
    [self setupStateWithBlockedUser];
    Плохо
    XCTAssertEqualObjects(err1, err2);
    - (void)testNil
    [self setupTestData];
    28
    

    View Slide

29. Нет лишнего контекста
    Хорошо
    [self stubServiceCompletionBlockWithError:error];
    - (void)setUp {}
    Плохо
    ...[invocation getArgument:&result atIndex:3];...
    ... self.interactor.output = OCMProtocolMock(...);...
    29
    

    View Slide

30. Тестируем одно поведение
    Хорошо
    ...
    XCTAssertTrue(viewReloaded);
    XCTAssertTrue(newDataIsShown);
    Плохо
    ...
    XCTAssertTrue(newUserSaved);
    XCTAssertFalse(viewReloaded);
    XCTAssertNil([self.service obtainSearchHistory]);
    30
    

    View Slide

31. OCMExpect([self.mockView setupInitialStateWithMenuItems:[OCMArg checkWithBlock:^BOOL(NSArray
    *menuItems) {
    __block BOOL correctSelectors = YES;
    [menuItems enumerateObjectsUsingBlock:^(ItemViewModel *menuItem, NSUInteger idx, BOOL stop) {
    NSString *expectedSelector = selectors[idx];
    if (![expectedSelector isEqualToString:NSStringFromSelector(menuItem.tapSelector)]) {
    correctSelectors = NO;
    }
    }];
    return correctSelectors && menuItems.count == selectors.count;
    }]]);
    31
    

    View Slide

32. OCMExpect([self.mockView setupInitialStateWithMenuItems:[OCMArg checkWithBlock:^BOOL(NSArray
    *menuItems) {
    __block BOOL correctSelectors = YES;
    [menuItems enumerateObjectsUsingBlock:^(ItemViewModel *menuItem, NSUInteger idx, BOOL stop) {
    NSString *expectedSelector = selectors[idx];
    if (![expectedSelector isEqualToString:NSStringFromSelector(menuItem.tapSelector)]) {
    correctSelectors = NO;
    }
    }];
    return correctSelectors && menuItems.count == selectors.count;
    }]]);
    self.mockView = [MockMenuView new];
    XCTAssertTrue(self.mockView.areAllSelectorsCorrect);
    32
    

    View Slide

33. // Случайная строка
    NSString *string = [[NSUUID UUID] UUIDString];
    // Произвольная ошибка
    NSError *error = [NSError errorWithDomain:@"TestDomain" code:0 userInfo:nil];
    33
    

    View Slide

34. // Случайная строка
    NSString *string = [[NSUUID UUID] UUIDString];
    // Произвольная ошибка
    NSError *error = [NSError errorWithDomain:@"TestDomain" code:0 userInfo:nil];
    NSString *string = [MockGenerator generateMockString];
    NSError *error = [MockGenerator generateMockError];
    34
    

    View Slide

35. - (void)setUp {
    [super setUp];
    RamblerInitialAssemblyCollector *collector = [RamblerInitialAssemblyCollector new];
    NSArray *assemblyClasses = [collector collectInitialAssemblyClasses];
    NSMutableArray *collaboratingAssemblies = [NSMutableArray array];
    for (Class assemblyClass in assemblyClasses) {
    if (assemblyClass == [NetworkAssembly class]) {
    continue;
    }
    TyphoonAssembly *assembly = [assemblyClass new];
    [collaboratingAssemblies addObject:assembly];
    }
    NetworkAssembly *networkAssembly = [NetworkAssembly new];
    [networkAssembly activateWithCollaboratingAssemblies:collaboratingAssemblies];
    [networkAssembly inject:self];
    }
    35
    

    View Slide

36. - (void)setUp {
    [super setUp];
    RamblerInitialAssemblyCollector *collector = [RamblerInitialAssemblyCollector new];
    NSArray *assemblyClasses = [collector collectInitialAssemblyClasses];
    NSMutableArray *collaboratingAssemblies = [NSMutableArray array];
    for (Class assemblyClass in assemblyClasses) {
    if (assemblyClass == [NetworkAssembly class]) {
    continue;
    }
    TyphoonAssembly *assembly = [assemblyClass new];
    [collaboratingAssemblies addObject:assembly];
    }
    NetworkAssembly *networkAssembly = [NetworkAssembly new];
    [networkAssembly activateWithCollaboratingAssemblies:collaboratingAssemblies];
    [networkAssembly inject:self];
    [MagicalRecord setupInMemoryCoreData];
    }
    - (void)setUp {
    [self setUpWithAssemblyClass:[NetworkAssembly class]];
    }
    36
    

    View Slide

37. - (void)testThatServiceLoadsSessionProfileSuccessfully {
    NSError *resultError;
    // большой блок логики загрузки профиля
    XCTAssertNil(resultError);
    }
    - (void)testThatServiceLoadsSessionProfileWithError {
    NSError *expectedError = [MockObjectsFactory generateGeneralError];
    // большой блок логики загрузки профиля
    XCTAssertEqualObjects(resultError, expectedError);
    }
    37
    

    View Slide

38. - (void)testThatServiceLoadsSessionProfileSuccessfully {
    NSError *resultError;
    // большой блок логики загрузки профиля
    XCTAssertNil(resultError);
    }
    - (void)testThatServiceLoadsSessionProfileWithError {
    NSError *expectedError = [MockObjectsFactory generateGeneralError];
    // большой блок логики загрузки профиля
    XCTAssertEqualObjects(resultError, expectedError);
    }
    - (void)testThatServiceLoadsProfileSuccessfully {
    [self verifyThatServiceLoadsProfileWithError:nil];
    }
    - (void)testThatServiceLoadsProfileWithError {
    [self verifyThatServiceLoadsProfileWithError:error];
    }
    - (void)verifyThatServiceLoadsProfileWithError:(id)error {
    ...
    }
    38
    

    View Slide

39. - (void)testThatPresenterStartsObservePost {
    NSString *postId = [MockObjectsFactory generateGeneralString];
    [self.presenter configureCurrentModuleWithPostId:postId];
    [self.presenter didTriggerViewReadyEvent];
    OCMVerify([self.mockInteractor startObserveChangesWithPostId:postId]);
    }
    39
    

    View Slide

40. - (void)testThatPresenterStartsObservePost {
    NSString *postId = [MockObjectsFactory generateGeneralString];
    [self.presenter configureCurrentModuleWithPostId:postId];
    [self.presenter didTriggerViewReadyEvent];
    OCMVerify([self.mockInteractor startObserveChangesWithPostId:postId]);
    }
    - (void)testThatPresenterStartsObservePost {
    // given
    NSString *postId = [MockObjectsFactory generateGeneralString];
    [self.presenter configureCurrentModuleWithPostId:postId];
    // when
    [self.presenter didTriggerViewReadyEvent];
    // then
    OCMVerify([self.mockInteractor startObserveChangesWithPostId:postId]);
    }
    40
    

    View Slide

41. Зачем нужны чистые тесты
    Как писать чистые тесты
    Рефакторим тест
    41
    

    View Slide

42. OperationScheduler
    queue1 queue2
    NSOperation NSOperation
    42
    

    View Slide

43. NSArray *operations = self.generalQueue.operations;
    for (NSOperation *generalOperation in operations) {
    [generalOperation addDependency:operation];
    }
    [self.authQueue addOperation:operation];
    43
    

    View Slide

44. • Передаем initialOperation в Планировщик
    • Передаем в Планировщик 5 generalOperation
    • При выполнении initialOperation создает authOperation
    initial > authorization > general (5x)
    44
    

    View Slide

45. - (void)testThatAuthOperationBlocksGeneralOperations {
    // given
    XCTestExpectation *expectation = [self expectationForCurrentTest];
    NSMutableArray *operationNames = [NSMutableArray array];
    NSString *const kAuthOperationName = @"AuthOperation";
    NSString *const kInitialOperationName = @"InitialOperation";
    NSString *const kGeneralOperationName = @"GeneralOperation";
    NSUInteger const kGeneralOperationsCount = 5;
    __block NSNumber *operationCounter = @0;
    NSBlockOperation *authOperation = [NSBlockOperation blockOperationWithBlock:^{
    dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{
    @synchronized(operationNames) {
    [operationNames addObject:kAuthOperationName];
    }
    [NSThread sleepForTimeInterval:0.05];
    });
    }];
    NSBlockOperation *initialOperation = [NSBlockOperation blockOperationWithBlock:^{
    @synchronized(operationNames) {
    [operationNames addObject:kInitialOperationName];
    }
    [self.scheduler addAuthOperation:authOperation];
    }];
    // when
    [self.scheduler addGeneralOperation:initialOperation];
    for (NSUInteger i = 0; i < kGeneralOperationsCount; i++) {
    NSBlockOperation *generalOperation = [NSBlockOperation blockOperationWithBlock:^{
    @synchronized(operationNames) {
    [operationNames addObject:kGeneralOperationName];
    }
    @synchronized(operationCounter) {
    operationCounter = @([operationCounter integerValue] + 1);
    if ([operationCounter integerValue] == kGeneralOperationsCount) {
    dispatch_async(dispatch_get_main_queue(), ^{
    [expectation fulfill];
    });
    }
    }
    }];
    [self.scheduler addGeneralOperation:generalOperation];
    }
    // then
    [self waitForExpectationsWithTimeout:kTestExpectationTimeout handler:^(NSError *error) {
    XCTAssertEqualObjects(operationNames[0], kInitialOperationName);
    XCTAssertEqualObjects(operationNames[1], kAuthOperationName);
    for (NSUInteger i = 2; i < kGeneralOperationsCount; i++) {
    XCTAssertEqualObjects(operationNames[i], kGeneralOperationName);
    }
    }];
    }
    45
    

    View Slide

46. XCTestExpectation *expectation =
    [self expectationWithDescription:@"Last operation fired"];
    XCTestExpectation *expectation =
    [self expectationForCurrentTest];
    46
    

    View Slide

47. NSString *const kAuthOperationName = @"AuthOperation";
    NSString *const kInitialOperationName = @"InitialOperation";
    NSString *const kGeneralOperationName = @"GeneralOperation";
    OperationSchedulerTestConstants.h
    47
    

    View Slide

48. NSBlockOperation *authOperation = [NSBlockOperation withBlock:^{
    dispatch_async(..., ^{
    @synchronized(operationNames) {
    [operationNames addObject:authName];
    }
    [NSThread sleep:0.05];
    });
    }];
    48
    

    View Slide

49. @interface TestBlockingByAuthOperationEnvironment : NSObject
    - (void)setupWithTestCase:(XCTestCase *)testCase
    operationsCount:(NSUInteger)operationsCount
    initialBlock:(Block)initialBlock;
    @property NSBlockOperation *initialOperation;
    @property NSBlockOperation *authOperation;
    @property NSArray *generalOperations;
    @property NSArray *firedOperationNames;
    @end
    49
    

    View Slide

50. TestBlockingByAuthOperationEnvironment *environment =
    [TestBlockingByAuthOperationEnvironment new];
    [environment setupWithTestCase:self
    operationsCount:kGeneralOperationsCount
    initialBlock:^{
    [self.scheduler addAuthOperation:environment.authOperation];
    for (NSOperation *operation in environment.generalOperations) {
    [self.scheduler addGeneralOperation:operation];
    }
    }];
    50
    

    View Slide

51. - (void)testThatAuthOperationBlocksGeneralOperations {
    // given
    NSUInteger const kGeneralOperationsCount = 5;
    TestBlockingByAuthOperationEnvironment *environment = [TestBlockingByAuthOperationEnvironment new];
    [environment setupEnvironmentWithTestCase:self
    generalOperationsCount:kGeneralOperationsCount
    initialOperationBlock:^{
    [self.scheduler addAuthOperation:environment.authOperation];
    for (NSOperation *operation in environment.generalOperations) {
    [self.scheduler addGeneralOperation:operation];
    }
    }];
    // when
    [self.scheduler addGeneralOperation:environment.initialOperation];
    // then
    [self waitForExpectationsWithTimeout:kTestExpectationTimeout handler:^(NSError *error) {
    [self verifyCorrectOperationOrder:kTestOrder];
    }];
    }
    51
    

    View Slide

52. Предметно-ориентированный язык
    Нет лишнего контекста
    Тестируем одно поведение
    52
    

    View Slide

53. What makes a clean test?
    Three things.
    Readability, readability,
    and readability.
    Егор Толстой
    @igrekde
    

    View Slide