Question

我一直试图找出如何使用OCMock为这种方法编写单元测试的方法。有人可以帮我吗？

- (void)executeRequest:(NSURLRequest *)request withCompletionHandler:(void (^)(id responseData, NSError *error))completionHandler
{
    NSURLSession *session = [NSURLSession sharedSession];
    NSURLSessionDataTask *dataTask = [session dataTaskWithRequest:request completionHandler:^(NSData *data, NSURLResponse *response, NSError *error) {
    if (error)
        {
            NSLog(@"Network error occurred: %@", [error localizedDescription]);
            dispatch_async(dispatch_get_main_queue(), ^(void) { completionHandler(nil, error);
            });
            return;
        }
    if ([response isKindOfClass:NSHTTPURLResponse.class])
    {
        NSInteger statusCode = [(NSHTTPURLResponse *)response statusCode];
        if (statusCode != 200)
        {
            NSLog(@"Network error occurred. Status code: %ld", (long)statusCode);
            return;
        }
    }
        completionHandler(data, nil);
    }];
    [dataTask resume];
}

Answer 1

您应该将OCMArg与checkWithBlock或invokeBlockWithArgs一起使用以测试完成处理程序。下面是一个示例：

通过单击Command + N创建XCTestCase子类：

为可测试实例和必要的模拟添加属性：

@interface SomeClassTests : XCTestCase

@property (nonatomic, strong) SomeClass *testableInstance;
@property (nonatomic, strong) NSURLSession *mockSession;
@property (nonatomic, strong) NSURLRequest *mockRequest;
@property (nonatomic, strong) NSHTTPURLResponse *mockResponse;

@end

设置属性：

- (void)setUp
{
    [super setUp];
    self.testableInstance = [SomeClass new];
    self.mockSession = OCMClassMock([NSURLSession class]);
    self.mockRequest = OCMClassMock([NSURLRequest class]);
    self.mockResponse = OCMClassMock([NSHTTPURLResponse class]);
    OCMStub(ClassMethod([(id)self.mockSession sharedSession])).andReturn(self.mockSession);
}

别忘了拆解时清理：

- (void)tearDown
{
    [(id)self.mockSession stopMocking];
    self.mockResponse = nil;
    self.mockRequest = nil;
    self.mockSession = nil;
    self.testableInstance = nil;
    [super tearDown];
}

让我们测试发生错误的情况：

- (void)testWhenErrorOccuersThenCompletionWithSameError
{
    // arrange
    NSError *givenError = [[NSError alloc] initWithDomain:@"Domain" code:0 userInfo:nil];
    OCMStub([self.mockSession dataTaskWithRequest:[OCMArg any] completionHandler:([OCMArg invokeBlockWithArgs:@"", self.mockResponse, givenError, nil])]);

    void (^givenCompletion)(id  _Nonnull, NSError * _Nonnull) = ^void(id  _Nonnull responseData, NSError * _Nonnull resultError) {
        // assert
        XCTAssertNil(responseData);
        XCTAssertEqual(resultError, givenError);
    };

    // act
    [self.testableInstance executeRequest:self.mockRequest withCompletionHandler:givenCompletion];
}

因此，我们将确保如果发生某些错误，则完成处理程序将在参数处调用相同的错误。

当我们收到一些错误的状态代码时让我们测试：

- (void)testWhenBadStatusCodeThenReturnWithoutCompletion
{
    // arrange
    OCMStub([self.mockResponse statusCode]).andReturn(403);
    OCMStub([self.mockSession dataTaskWithRequest:[OCMArg any] completionHandler:([OCMArg checkWithBlock:^BOOL(id param) {
        void (^passedCompletion)(NSData *data, NSURLResponse *response, NSError *error) = param;
        passedCompletion(nil, self.mockResponse, nil);
        return YES;
    }])]);

    void (^givenCompletion)(id  _Nonnull, NSError * _Nonnull) = ^void(id  _Nonnull responseData, NSError * _Nonnull resultError) {
        // assert
        XCTFail("Shouldn't be reached");
    };

    // act
    [self.testableInstance executeRequest:self.mockRequest withCompletionHandler:givenCompletion];
}

最后让我们测试何时实际获取数据：

- (void)testWhenSuccesThenCompletionWithSameData
{
    // arrange
    NSData *givenData = [NSData data];
    OCMStub([self.mockResponse statusCode]).andReturn(200);
    OCMStub([self.mockSession dataTaskWithRequest:[OCMArg any] completionHandler:([OCMArg checkWithBlock:^BOOL(id param) {
        void (^passedCompletion)(NSData *data, NSURLResponse *response, NSError *error) = param;
        passedCompletion(givenData, self.mockResponse, nil);
        return YES;
    }])]);

    void (^givenCompletion)(id  _Nonnull, NSError * _Nonnull) = ^void(id  _Nonnull responseData, NSError * _Nonnull resultError) {
        // assert
        XCTAssertEqual(responseData, givenData);
    };

    // act
    [self.testableInstance executeRequest:self.mockRequest withCompletionHandler:givenCompletion];
}

如果您打开覆盖范围，那么您将看到这样的测试完全覆盖了可测试的代码：

如何为带有返回数据的完成处理程序的方法编写单元测试？

1 个答案: