«Как сделать так, чтобы тесты на Swift не причиняли боль» Сычев Александр, Rambler&Co
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The document discusses best practices for writing tests in Swift, including recommendations to: - Write clean, readable tests that focus on asserting a single truth - Use a domain-specific language in tests for clarity - Structure tests with "given-when-then" - Mock dependencies through protocols to enable test isolation - Favor partial mocks over fully mocking to limit complexity
![Tests in Swift
- (void)testThatObjectsWithEqualTitleAreEqual {
// given
RubricsObject *object1 = [[RubricsObject alloc] initWithTagID:@"tagID1"
title:@"Title"];
RubricsObject *object2 = [[RubricsObject alloc] initWithTagID:@"tagID2"
title:@"Title"];
// when
BOOL equal = [object1 isEqual:object2];
// then
XCTAssertTrue(equal);
}](https://image.slidesharecdn.com/nn-170425070316/85/Swift-Rambler-Co-14-320.jpg)
![Tests in Swift
- (void)testThatObjectsWithEqualTitleAreEqual {
// given
RubricsObject *object1 = [[RubricsObject alloc] initWithTagID:@"tagID1"
title:@"Title"];
RubricsObject *object2 = [[RubricsObject alloc] initWithTagID:@"tagID2"
title:@"Title"];
// when
BOOL equal = [object1 isEqual:object2];
// then
XCTAssertTrue(equal);
}
// given
// when
// then](https://image.slidesharecdn.com/nn-170425070316/85/Swift-Rambler-Co-15-320.jpg)
![Tests in Swift
- (void)testThatObjectsWithEqualTitleAreEqual {
// given
RubricsObject *object1 = [[RubricsObject alloc] initWithTagID:@"tagID1"
title:@"Title"];
RubricsObject *object2 = [[RubricsObject alloc] initWithTagID:@"tagID2"
title:@"Title"];
// when
BOOL equal = [object1 isEqual:object2];
// then
XCTAssertTrue(equal);
}
// given
// when
// then](https://image.slidesharecdn.com/nn-170425070316/85/Swift-Rambler-Co-16-320.jpg)
![Tests in Swift
- (void)testThatObjectsWithEqualTitleAreEqual {
// given
RubricsObject *object1 = [[RubricsObject alloc] initWithTagID:@"tagID1"
title:@"Title"];
RubricsObject *object2 = [[RubricsObject alloc] initWithTagID:@"tagID2"
title:@"Title"];
// when
BOOL equal = [object1 isEqual:object2];
// then
XCTAssertTrue(equal);
}
// given
// when
// then](https://image.slidesharecdn.com/nn-170425070316/85/Swift-Rambler-Co-17-320.jpg)
![Tests in Swift
- (void)testThatObjectsWithEqualTitleAreEqual {
// given
RubricsObject *object1 = [[RubricsObject alloc] initWithTagID:@"tagID1"
title:@"Title"];
RubricsObject *object2 = [[RubricsObject alloc] initWithTagID:@"tagID2"
title:@"Title"];
// when
BOOL equal = [object1 isEqual:object2];
// then
XCTAssertTrue(equal);
}
// given
// when
// then](https://image.slidesharecdn.com/nn-170425070316/85/Swift-Rambler-Co-18-320.jpg)
![Tests in Swift
Предметно-ориентированный язык
- (void)test1 {
RubricsObject *obj = [RubricsObject new];
XCTAssertEqualObjects(obj1, obj2);
}](https://image.slidesharecdn.com/nn-170425070316/85/Swift-Rambler-Co-21-320.jpg)
![Tests in Swift
Предметно-ориентированный язык
- (void)test1 {
RubricsObject *obj = [RubricsObject new];
XCTAssertEqualObjects(obj1, obj2);
}](https://image.slidesharecdn.com/nn-170425070316/85/Swift-Rambler-Co-22-320.jpg)
![Tests in Swift
- (void)testThatObjectsWithEqualTitleAreEqual {
// given
RubricsObject *object1 = [[RubricsObject alloc] initWithTagID:@"tagID1"
title:@"Title"];
RubricsObject *object2 = [[RubricsObject alloc] initWithTagID:@"tagID2"
title:@"Title"];
// when
BOOL equal = [object1 isEqual:object2];
// then
XCTAssertTrue(equal);
}](https://image.slidesharecdn.com/nn-170425070316/85/Swift-Rambler-Co-24-320.jpg)
![Tests in Swift
Нет лишнего контекста
- (void)testThatMailBoxServiceObtainesCachedConnectedMailBoxConfigList {
// given
NSString *firstMailBoxNativeFolderName = @"firstFolder";
NSString *secondMailBoxNativeFolderName = @"secondFolder";
NSManagedObjectContext *managedObjectContext = [NSManagedObjectContext MR_rootSavingContext];
[managedObjectContext performBlockAndWait:^{
RCMMailBox *firstMailBox = [RCMMailBox MR_createEntityInContext:managedObjectContext];
firstMailBox.nativeFolder = firstMailBoxNativeFolderName;
RCMMailBox *secondMailBox = [RCMMailBox MR_createEntityInContext:managedObjectContext];
secondMailBox.nativeFolder = secondMailBoxNativeFolderName;
[managedObjectContext MR_saveOnlySelfAndWait];
}];
// when
NSArray *mailBoxList = [self.mailBoxService obtainCachedConnectedMailBoxConfigList];
// then
BOOL containsFirstMailBox;
BOOL containsSecondMailBox;
for (id<RCMMailBoxConfig> mailBoxConfig in mailBoxList) {
if ([mailBoxConfig.nativeFolder isEqualToString:firstMailBoxNativeFolderName]) {
containsFirstMailBox = YES;
}
else if ([mailBoxConfig.nativeFolder isEqualToString:secondMailBoxNativeFolderName]) {
containsSecondMailBox = YES;
}
}
XCTAssertTrue(containsFirstMailBox);
XCTAssertTrue(containsSecondMailBox);
}](https://image.slidesharecdn.com/nn-170425070316/85/Swift-Rambler-Co-25-320.jpg)
![Tests in Swift
Нет лишнего контекста
- (void)testThatMailBoxServiceObtainesCachedConnectedMailBoxConfigList {
// given
NSString *firstMailBoxNativeFolderName = @"firstFolder";
NSString *secondMailBoxNativeFolderName = @"secondFolder";
NSManagedObjectContext *managedObjectContext = [NSManagedObjectContext MR_rootSavingContext];
[managedObjectContext performBlockAndWait:^{
RCMMailBox *firstMailBox = [RCMMailBox MR_createEntityInContext:managedObjectContext];
firstMailBox.nativeFolder = firstMailBoxNativeFolderName;
RCMMailBox *secondMailBox = [RCMMailBox MR_createEntityInContext:managedObjectContext];
secondMailBox.nativeFolder = secondMailBoxNativeFolderName;
[managedObjectContext MR_saveOnlySelfAndWait];
}];
// when
NSArray *mailBoxList = [self.mailBoxService obtainCachedConnectedMailBoxConfigList];
// then
BOOL containsFirstMailBox;
BOOL containsSecondMailBox;
for (id<RCMMailBoxConfig> mailBoxConfig in mailBoxList) {
if ([mailBoxConfig.nativeFolder isEqualToString:firstMailBoxNativeFolderName]) {
containsFirstMailBox = YES;
}
else if ([mailBoxConfig.nativeFolder isEqualToString:secondMailBoxNativeFolderName]) {
containsSecondMailBox = YES;
}
}
XCTAssertTrue(containsFirstMailBox);
XCTAssertTrue(containsSecondMailBox);
}
😱](https://image.slidesharecdn.com/nn-170425070316/85/Swift-Rambler-Co-26-320.jpg)
![Tests in Swift
Mocks
NSURLSession *mock = OCMClassMock([NSURLSession class]);](https://image.slidesharecdn.com/nn-170425070316/85/Swift-Rambler-Co-55-320.jpg)
![Tests in Swift
Mocks
NSURLSession *mock = OCMClassMock([NSURLSession class]);](https://image.slidesharecdn.com/nn-170425070316/85/Swift-Rambler-Co-56-320.jpg)
«Как сделать так, чтобы тесты на Swift не причиняли боль» Сычев Александр, Rambler&Co
- 1. Александр Сычев Как сделать так, чтобы тесты на Swift не причиняли боль 🤕
- 2. Tests in Swift Александр Сычев a.sychev@rambler-co.ru @asychev89
- 3. Tests in Swift • Требования к тестам • Что мы поменяли • Swift-style тесты • Советы и рекомендации
- 7. Tests in Swift Преимущества • Понимание требований • Стабильность при рефакторинге • Документация • Хороший API • Меньше ошибок
- 8. Tests in Swift Преимущества • Понимание требований • Стабильность при рефакторинге • Документация • Хороший API • Меньше ошибок
- 9. Tests in Swift Преимущества • Понимание требований • Стабильность при рефакторинге • Документация • Хороший API • Меньше ошибок
- 10. Tests in Swift Преимущества • Понимание требований • Стабильность при рефакторинге • Документация • Хороший API • Меньше ошибок
- 11. Tests in Swift Преимущества • Понимание требований • Стабильность при рефакторинге • Документация • Хороший API • Меньше ошибок
- 14. Tests in Swift - (void)testThatObjectsWithEqualTitleAreEqual { // given RubricsObject *object1 = [[RubricsObject alloc] initWithTagID:@"tagID1" title:@"Title"]; RubricsObject *object2 = [[RubricsObject alloc] initWithTagID:@"tagID2" title:@"Title"]; // when BOOL equal = [object1 isEqual:object2]; // then XCTAssertTrue(equal); }
- 15. Tests in Swift - (void)testThatObjectsWithEqualTitleAreEqual { // given RubricsObject *object1 = [[RubricsObject alloc] initWithTagID:@"tagID1" title:@"Title"]; RubricsObject *object2 = [[RubricsObject alloc] initWithTagID:@"tagID2" title:@"Title"]; // when BOOL equal = [object1 isEqual:object2]; // then XCTAssertTrue(equal); } // given // when // then
- 16. Tests in Swift - (void)testThatObjectsWithEqualTitleAreEqual { // given RubricsObject *object1 = [[RubricsObject alloc] initWithTagID:@"tagID1" title:@"Title"]; RubricsObject *object2 = [[RubricsObject alloc] initWithTagID:@"tagID2" title:@"Title"]; // when BOOL equal = [object1 isEqual:object2]; // then XCTAssertTrue(equal); } // given // when // then
- 17. Tests in Swift - (void)testThatObjectsWithEqualTitleAreEqual { // given RubricsObject *object1 = [[RubricsObject alloc] initWithTagID:@"tagID1" title:@"Title"]; RubricsObject *object2 = [[RubricsObject alloc] initWithTagID:@"tagID2" title:@"Title"]; // when BOOL equal = [object1 isEqual:object2]; // then XCTAssertTrue(equal); } // given // when // then
- 18. Tests in Swift - (void)testThatObjectsWithEqualTitleAreEqual { // given RubricsObject *object1 = [[RubricsObject alloc] initWithTagID:@"tagID1" title:@"Title"]; RubricsObject *object2 = [[RubricsObject alloc] initWithTagID:@"tagID2" title:@"Title"]; // when BOOL equal = [object1 isEqual:object2]; // then XCTAssertTrue(equal); } // given // when // then
- 19. Tests in Swift What makes a clean test? Three things. Readability, readability, and readability. Robert C. Martin
- 20. Tests in Swift • Предметно-ориентированный язык • Нет лишнего контекста • Проверка одной истины Чистый тест
- 21. Tests in Swift Предметно-ориентированный язык - (void)test1 { RubricsObject *obj = [RubricsObject new]; XCTAssertEqualObjects(obj1, obj2); }
- 22. Tests in Swift Предметно-ориентированный язык - (void)test1 { RubricsObject *obj = [RubricsObject new]; XCTAssertEqualObjects(obj1, obj2); }
- 24. Tests in Swift - (void)testThatObjectsWithEqualTitleAreEqual { // given RubricsObject *object1 = [[RubricsObject alloc] initWithTagID:@"tagID1" title:@"Title"]; RubricsObject *object2 = [[RubricsObject alloc] initWithTagID:@"tagID2" title:@"Title"]; // when BOOL equal = [object1 isEqual:object2]; // then XCTAssertTrue(equal); }
- 25. Tests in Swift Нет лишнего контекста - (void)testThatMailBoxServiceObtainesCachedConnectedMailBoxConfigList { // given NSString *firstMailBoxNativeFolderName = @"firstFolder"; NSString *secondMailBoxNativeFolderName = @"secondFolder"; NSManagedObjectContext *managedObjectContext = [NSManagedObjectContext MR_rootSavingContext]; [managedObjectContext performBlockAndWait:^{ RCMMailBox *firstMailBox = [RCMMailBox MR_createEntityInContext:managedObjectContext]; firstMailBox.nativeFolder = firstMailBoxNativeFolderName; RCMMailBox *secondMailBox = [RCMMailBox MR_createEntityInContext:managedObjectContext]; secondMailBox.nativeFolder = secondMailBoxNativeFolderName; [managedObjectContext MR_saveOnlySelfAndWait]; }]; // when NSArray *mailBoxList = [self.mailBoxService obtainCachedConnectedMailBoxConfigList]; // then BOOL containsFirstMailBox; BOOL containsSecondMailBox; for (id<RCMMailBoxConfig> mailBoxConfig in mailBoxList) { if ([mailBoxConfig.nativeFolder isEqualToString:firstMailBoxNativeFolderName]) { containsFirstMailBox = YES; } else if ([mailBoxConfig.nativeFolder isEqualToString:secondMailBoxNativeFolderName]) { containsSecondMailBox = YES; } } XCTAssertTrue(containsFirstMailBox); XCTAssertTrue(containsSecondMailBox); }
- 26. Tests in Swift Нет лишнего контекста - (void)testThatMailBoxServiceObtainesCachedConnectedMailBoxConfigList { // given NSString *firstMailBoxNativeFolderName = @"firstFolder"; NSString *secondMailBoxNativeFolderName = @"secondFolder"; NSManagedObjectContext *managedObjectContext = [NSManagedObjectContext MR_rootSavingContext]; [managedObjectContext performBlockAndWait:^{ RCMMailBox *firstMailBox = [RCMMailBox MR_createEntityInContext:managedObjectContext]; firstMailBox.nativeFolder = firstMailBoxNativeFolderName; RCMMailBox *secondMailBox = [RCMMailBox MR_createEntityInContext:managedObjectContext]; secondMailBox.nativeFolder = secondMailBoxNativeFolderName; [managedObjectContext MR_saveOnlySelfAndWait]; }]; // when NSArray *mailBoxList = [self.mailBoxService obtainCachedConnectedMailBoxConfigList]; // then BOOL containsFirstMailBox; BOOL containsSecondMailBox; for (id<RCMMailBoxConfig> mailBoxConfig in mailBoxList) { if ([mailBoxConfig.nativeFolder isEqualToString:firstMailBoxNativeFolderName]) { containsFirstMailBox = YES; } else if ([mailBoxConfig.nativeFolder isEqualToString:secondMailBoxNativeFolderName]) { containsSecondMailBox = YES; } } XCTAssertTrue(containsFirstMailBox); XCTAssertTrue(containsSecondMailBox); } 😱
- 27. Tests in Swift Extract Method
- 28. Tests in Swift Проверка одной истины assert one truth
- 29. Tests in Swift Требования • Скорость • Надежность
- 30. Tests in Swift Требования • Скорость • Надежность 🚀
- 31. Tests in Swift Требования • Скорость • Надежность
- 33. Tests in Swift • Требования к тестам • Что мы поменяли • Swift-style тесты • Советы и рекомендации
- 34. Tests in Swift НИЧЕГО ☺
- 35. Tests in Swift
- 36. Tests in Swift
- 37. Tests in Swift
- 38. Tests in Swift
- 39. Tests in Swift • Требования к тестам • Что мы поменяли • Swift-style тесты • Советы и рекомендации
- 41. Tests in Swift Assertions public func XCTFail(_ message: String = default, file: StaticString = #file, line: UInt = #line)
- 42. Tests in Swift func testExample() { // given // when // then XCTFail("message") } Assertions
- 43. Tests in Swift func testExample() { // given let pair = (20, 16) // when // then XCTAssertEqual(pair, (20, 17)) } Assertions
- 44. Tests in Swift func testExample() { // given let pair = (20, 16) // when // then XCTAssertEqual(pair, (20, 17)) } Assertions
- 45. Tests in Swift func testExample() { // given let pair = (20, 16) // when // then XCTAssert(pair == (20, 17)) } Assertions
- 48. Tests in Swift Write a custom test assertion
- 49. Tests in Swift func assertIntPairsEqual(actual: (_: Int, _: Int), expected: (_: Int, _: Int), file: StaticString = #file, line: UInt = #line) { if actual != expected { XCTFail("Expected (expected) but was (actual)", file: file, line: line) } } Custom assertions
- 50. Tests in Swift func assertIntPairsEqual(actual: (_: Int, _: Int), expected: (_: Int, _: Int), file: StaticString = #file, line: UInt = #line) { if actual != expected { XCTFail("Expected (expected) but was (actual)", file: file, line: line) } } Custom assertions
- 51. Tests in Swift func assertIntPairsEqual(actual: (_: Int, _: Int), expected: (_: Int, _: Int), file: StaticString = #file, line: UInt = #line) { if actual != expected { XCTFail("Expected (expected) but was (actual)", file: file, line: line) } } Custom assertions
- 52. Tests in Swift Custom assertions
- 53. Tests in Swift func assertPairsEqual<T: Equatable, U: Equatable>(actual: (_: T, _: U), expected: (_: T, _: U), file: StaticString = #file, line: UInt = #line) Custom assertions
- 55. Tests in Swift Mocks NSURLSession *mock = OCMClassMock([NSURLSession class]);
- 56. Tests in Swift Mocks NSURLSession *mock = OCMClassMock([NSURLSession class]);
- 57. Tests in Swift Protocols and Extensions
- 58. Tests in Swift struct ToDoService { init(session: URLSession) { // … } } let service = ToDoService(session: URLSession.shared) Mocks
- 59. Tests in Swift struct ToDoService { init(session: URLSession) { // … } } let service = ToDoService(session: URLSession.shared) Mocks
- 60. Tests in Swift protocol URLSessionProtocol {} extension URLSession: URLSessionProtocol {} struct ToDoService { init(session: URLSessionProtocol) { // … } } Mocks
- 61. Tests in Swift protocol URLSessionProtocol {} extension URLSession: URLSessionProtocol {} struct ToDoService { init(session: URLSessionProtocol) { // … } } Mocks
- 62. Tests in Swift protocol URLSessionProtocol {} extension URLSession: URLSessionProtocol {} struct ToDoService { init(session: URLSessionProtocol) { // … } } Mocks
- 63. Tests in Swift protocol URLSessionProtocol {} extension URLSession: URLSessionProtocol {} struct ToDoService { init(session: URLSessionProtocol) { // … } } Mocks
- 64. Tests in Swift let service = ToDoService(session: URLSession.shared) Mocks
- 65. Tests in Swift class MockURLSession: URLSessionProtocol {} Mocks
- 66. Tests in Swift protocol URLSessionProtocol { func dataTask(request: URLRequest, completion:(Data?, Response?, Error?) -> Void) -> DataTask } Mocks
- 67. Tests in Swift class MockURLSession: URLSessionProtocol { func dataTask(with …) -> URLSessionDataTask { return URLSessionDataTask() } } Mocks
- 68. Tests in Swift 1. Число вызовов 2. Переданные аргументы Mocks
- 69. Tests in Swift class MockURLSession: URLSessionProtocol { var dataTaskCallCount = 0 func dataTask(with …) -> URLSessionDataTask { dataTaskCallCount += 1 return URLSessionDataTask() } } Mocks
- 70. Tests in Swift func testExample() { // given ... // when ... // then XCTAssertEqual(mockURLSession.dataTaskCallCount, 1) } Mocks
- 71. Tests in Swift class MockURLSession: URLSessionProtocol { var dataTaskLastURL: URL? func dataTask(with …) -> URLSessionDataTask { dataTaskLastURL = url return URLSessionDataTask() } } Mocks
- 72. Tests in Swift func testExample() { // given ... // when ... // then XCTAssertEqual(mockURLSession.dataTaskLastURL?.host, "http://expected.com") } Mocks
- 73. Tests in Swift 1. Используйте вспомогательные методы для одной проверки 2. Накапливайте аргументы в коллекциях Mocks
- 74. Tests in Swift Partial mocks
- 75. Tests in Swift class MockURLSessionDataTask: URLSessionDataTask { private var resumeCallCount = 0 override func resume() { resumeCallCount += 1 } func verifyResume() { XCTAssertEqual(resumeCallCount, 1) } } Partial mocks
- 76. Tests in Swift class MockURLSession: URLSessionProtocol { var dataTaskReturnValue: URLSessionDataTask! func dataTask(with …) -> URLSessionDataTask { return dataTaskReturnValue } } Partial mocks
- 77. Tests in Swift func testExample() { // given let mockDataTask = MockURLSessionDataTask() mockURLSession.dataTaskReturnValue = mockDataTask // when … // then mockDataTask.verifyResume() } Partial mocks
- 78. Tests in Swift Partial mocks 💩
- 79. Tests in Swift Mocks • Избегайте моков • Используйте Protocols • Используйте Partial mocks
- 81. Tests in Swift func testAnOptional() throws { // given let string: String? = nil // when ... // then guard let newString = string else { throw UnexpectedNilError() } XCTAssert(newString.lengthOfBytes(using: .utf8) > 0) } Optionals
- 82. Tests in Swift struct UnexpectedNilError: Error {} func AssertNotNilAndUnwrap<T>(_ variable: T?, message: String = "Error", file: StaticString = #file, line: UInt = #line) throws -> T { guard let variable = variable else { XCTFail(message, file: file, line: line) throw UnexpectedNilError() } return variable } Optionals
- 83. Tests in Swift • Требования к тестам • Что мы поменяли • Swift-style тесты • Советы и рекомендации
- 84. Tests in Swift Библиотеки • SwiftyMock • Kakapo 🐤 • Dobby • MockFive • Cuckoo
- 85. Tests in Swift Библиотеки • SwiftyMock • Kakapo 🐤 • Dobby • MockFive • Cuckoo
- 87. Tests in Swift Библиотеки OUTPUT_FILE="$PROJECT_DIR/Tests/ GeneratedMocks.swift" echo "Generated Mocks File = $OUTPUT_FILE" INPUT_DIR="$PROJECT_DIR" echo "Mocks Input Directory = $INPUT_DIR" ${PODS_ROOT}/Cuckoo/run generate --testable "$PROJECT_NAME" --output "${OUTPUT_FILE}" "$INPUT_DIR/FileName1.swift" "$INPUT_DIR/FileName2.swift" "$INPUT_DIR/FileName3.swift"
- 88. Tests in Swift Библиотеки OUTPUT_FILE="$PROJECT_DIR/Tests/ GeneratedMocks.swift" echo "Generated Mocks File = $OUTPUT_FILE" INPUT_DIR="$PROJECT_DIR" echo "Mocks Input Directory = $INPUT_DIR" ${PODS_ROOT}/Cuckoo/run generate --testable "$PROJECT_NAME" --output "${OUTPUT_FILE}" "$INPUT_DIR/FileName1.swift" "$INPUT_DIR/FileName2.swift" "$INPUT_DIR/FileName3.swift"
- 93. Tests in Swift a.sychev@rambler-co.ru @asychev89 What makes a clean test? Three things. Readability, readability, and readability. Robert C. Martin