Question

我正在关注Test driven iOS Development中的示例，并且在一个案例中，有一个单元测试可以确保委托获得错误方法的'dumbed down'版本。因此，这里没有涉及太多细节的相关对象：

communicator：负责进行网络通话的对象
经理：指示通讯员拨打电话，然后将结果推送给其代表。
委托：符合StackOverflowManagerDelegate协议的经理委托。得到结果并处理它。

所以测试是这样的：

@implementation QuestionCreationTests

{
    @private
    StackOverflowManager *mgr;
}
- (void)testErrorReturnedToDelegateIsNotErrorNotifiedByCommunicator {
    MockStackOverflowManagerDelegate *delegate =
    [[MockStackOverflowManagerDelegate alloc] init];
    mgr.delegate = delegate;
    NSError *underlyingError = [NSError errorWithDomain: @"Test domain"
                                                   code: 0 userInfo: nil];
    [mgr searchingForQuestionsFailedWithError: underlyingError];
    XCTAssertFalse(underlyingError == [delegate fetchError],
                  @"Error should be at the correct level of abstraction");
}

这是StackOverflowManager中searchingForQuestionsFailedWithError的实现，其中管理器只是简化了通信器返回的原始错误，并将愚蠢的版本发送给代理。

- (void)searchingForQuestionsFailedWithError:(NSError *)error {
    NSDictionary *errorInfo = [NSDictionary dictionaryWithObject: error
                                                          forKey: NSUnderlyingErrorKey];
    NSError *reportableError = [NSError
                                errorWithDomain: StackOverflowManagerSearchFailedError
                                code: StackOverflowManagerErrorQuestionSearchCode
                                userInfo:errorInfo];
    [delegate fetchingQuestionsOnTopic: nil
                       failedWithError: reportableError];
}

作者建议为此工作..我们实际上必须为管理员委托创建一个模拟对象，如下所示：

@interface MockStackOverflowManagerDelegate : NSObject <StackOverflowManagerDelegate>
@property (strong) NSError *fetchError;

@end

@implementation MockStackOverflowManagerDelegate

@synthesize fetchError;

- (void)fetchingQuestionsOnTopic: (Topic *)topic
                 failedWithError: (NSError *)error {
    self.fetchError = error;
}

@end

这是StackOverflowManagerDelegate：

的声明

@protocol StackOverflowManagerDelegate <NSObject>    
- (void)fetchingQuestionsOnTopic: (Topic *)topic
                 failedWithError: (NSError *)error {    
@end

问题我一直在查看本书的所有示例，并试图使用OCMock而不是像作者那样手工制作的那些..（我只是觉得它会是一个更少的时间）。到目前为止一切都工作了..但我被困在这里..如何在委托上伪造一个名为fetchError的属性？这就是我现在所拥有的：

- (void)testErrorReturnedToDelegateIsNotErrorNotifiedByCommunicator {
    id <StackOverflowManagerDelegate> delegate = 
       [OCMockObject mockForProtocol:@protocol(StackOverflowManagerDelegate)];
    mgr.delegate = delegate;

    NSError *underlyingError = [NSError errorWithDomain: @"Test domain"
                                                   code: 0 userInfo: nil];

    [mgr searchingForQuestionsFailedWithError: underlyingError];

    // compiler error here: no known instance method for selector 'fetchError'
    XCTAssertFalse(underlyingError == [mgr.delegate fetchError], @"error ");
}

在经理的胆量中，经理在委托上调用fetchingQuestionsOnTopic ..我知道我可以通过using [[[delegate stub] andCall:@selector(differentMethod:) onObject:differentObject] fetchingQuestionsOnTopic:[OCMArg any]]伪造该方法，其中differentMethod会做我想做的任何事情它要做..我只是不知道如何处理differentMethod的结果：我不知道如何将它存储在委托的模拟属性中。

更新：作为以下答案的后续内容。这里是单元测试的实现，可确保代理人仍然可以使用基础错误：

- (void)testErrorReturnedToDelegateDocumentsUnderlyingError {
    MockStackOverflowManagerDelegate *delegate =
    [[MockStackOverflowManagerDelegate alloc] init];
    mgr.delegate = delegate;
    NSError *underlyingError = [NSError errorWithDomain: @"Test domain"
                                                   code: 0 userInfo: nil];
    [mgr searchingForQuestionsFailedWithError: underlyingError];
    XCTAssertEqual([[[delegate fetchError] userInfo]
                          objectForKey: NSUnderlyingErrorKey], underlyingError,
                         @"The underlying error should be available to client code");
}

以下是它的OCMock版本：

- (void)testErrorReturnedToDelegateDocumentsUnderlyingErrorOCMock {
    id delegate =
    [OCMockObject mockForProtocol:@protocol(StackOverflowManagerDelegate)];
    mgr.delegate = delegate;

    NSError *underlyingError = [NSError errorWithDomain: @"Test domain"
                                                   code: 0 userInfo: nil];

    [[delegate expect] fetchingQuestionsFailedWithError:
       [OCMArg checkWithBlock:^BOOL(id param) {

        return ([[param userInfo] objectForKey:NSUnderlyingErrorKey] == underlyingError);

    }]];

    [mgr searchingForQuestionsFailedWithError: underlyingError];

    [delegate verify];

}

Answer 1

试试这个：

- (void)testErrorReturnedToDelegateIsNotErrorNotifiedByCommunicator {
    id delegate = 
       [OCMockObject mockForProtocol:@protocol(StackOverflowManagerDelegate)];
    mgr.delegate = delegate;

    NSError *underlyingError = [NSError errorWithDomain: @"Test domain"
                                                   code: 0 userInfo: nil];

    [[delegate expect] fetchingQuestionsOnTopic:OCMOCK_ANY 
                                failedWithError:[OCMArg isNotEqual:underlyingError]];

    [mgr searchingForQuestionsFailedWithError:underlyingError];

    [delegate verify];
}

要测试经理报告的错误的域名，代码和userInfo（如果我记得那本书中的另一个测试用例 - 我很久以前就读过它了）你可以这样做：

    id <StackOverflowManagerDelegate> delegate = 
       [OCMockObject mockForProtocol:@protocol(StackOverflowManagerDelegate)];
    mgr.delegate = delegate;

    NSError *underlyingError = [NSError errorWithDomain: @"Test domain"
                                                   code: 0 userInfo: nil];

    NSError *expectedError = [NSError errorWithDomain:@"expected domain" 
                                                 code:0/* expected code here*/ 
                                             userInfo:@{NSUnderlyingErrorKey: underlyingError}];
    [[delegate expect] fetchingQuestionsOnTopic:OCMOCK_ANY 
                                failedWithError:expectedError];

    [mgr searchingForQuestionsFailedWithError: underlyingError];

    [delegate verify];

如何模拟符合协议的对象的属性并由OCMock嘲笑？

1 个答案: