如何使用 OCMock 在 XCTestCase 的方法中访问局部变量？答案

【问题标题】：How can I access local variables within a method for an XCTestCase using OCMock?如何使用 OCMock 在 XCTestCase 的方法中访问局部变量？
【发布时间】：2014-08-03 11:02:33
【问题描述】：

我有一个我想测试的方法：

- (void)openEmailFeedback
{
    MFMailComposeViewController* controller = [[MFMailComposeViewController alloc] init];
    controller.mailComposeDelegate = self;
    [controller setToRecipients:@"test@example.com"];
    [controller setSubject:@""];
    [controller setMessageBody:@"" isHTML:NO];
    [self presentViewController:controller animated:YES completion:nil];
}

我尝试用它测试它

- (void)testOpenEmailFeedback
{
    ViewController *vc = [[ViewController alloc] init];

    // Create a partial mock of UIApplication
    id mockMailComposeViewController = [OCMockObject mockForClass:[MFMailComposeViewController class]];
    [[mockMailComposeViewController expect] setMailComposeDelegate:vc];
    [[mockMailComposeViewController expect] setToRecipients:@[@"test@example.com"]];
    [[mockMailComposeViewController expect] setSubject:@""];
    [[mockMailComposeViewController expect] setMessageBody:@"" isHTML:NO];

    [vc openEmailFeedback];

    [mockMailComposeViewController verify];
    [mockMailComposeViewController stopMocking];
}

但我意识到 mockMailComposeViewController 与方法中的本地 MFMailComposeViewController *controller 远非同一个变量。测试时是否可以在“openEmailFeedback”方法中访问局部变量？

【问题讨论】：

标签： ios objective-c ocmock xctest

【解决方案1】：

这个问题的标准答案是使用依赖注入模式。对于 OCMock 和部分模拟，您还可以使用另一种模式。只需在具有依赖项和存根的类中创建一个工厂方法。在您的视图控制器中：

- (MFMailComposeViewController *)createComposeViewController
{
    return [[MFMailComposeViewController alloc] init];
}

- (void)openEmailFeedback
{
    MFMailComposeViewController* controller = [self createComposeViewController];
    controller.mailComposeDelegate = self;
    // continue as normal...

在你的测试中：

- (void)testOpenEmailFeedback
{
ViewController *vc = [[ViewController alloc] init];

// Create a partial mock of UIApplication
id mockMailComposeViewController = [OCMockObject mockForClass:[MFMailComposeViewController class]];
[[mockMailComposeViewController expect] setMailComposeDelegate:vc];
[[mockMailComposeViewController expect] setToRecipients:@[@"test@example.com"]];
[[mockMailComposeViewController expect] setSubject:@""];
[[mockMailComposeViewController expect] setMessageBody:@"" isHTML:NO];

 id vcPartialMock = [OCMockObject partialMockForObject:vc];
 [[[vcPartialMock stub] andReturn:mockMailComposeViewController] createComposeViewController];

 // continue as before...

【讨论】：

【解决方案2】：

我通常使用这种模式在我正在测试的方法中模拟本地创建的对象-

MyClass *instance = [[MyClass alloc] init];
id mockMyClassObj = [OCMockObject mockForClass:[MyClass class]];
[[[mockMyClassObj stub] andReturn:instance] alloc];

然后在断言中 -

// Lets say I am testing for property 'whatever' being nil after calling the method I am testing
XCTAssertNil(instance.whatever, @"whatever should be nil");

这是该代码的 Xcode sn-p -

<#Class#> *<#instance#> = [[<#Class#> alloc] init];
id mock<#name#> = [OCMockObject mockForClass:[<#class#> class]];
[[[mock<#name#> stub] andReturn:<#instance#>] alloc];

【讨论】：