ios - 调用 [NSBundle mainBundle] 时 XCTest 失败

Question

我有一些代码在某些时候调用[NSBundle mainBundle]，主要是为了读取/设置首选项。当我对该方法进行单元测试时，测试失败，因为测试的 mainBundle 不包含该文件。

这是 a known issue ，Apple 不会修复，因为他们认为它是 not a bug :

the gist of their reply is that XCTest is working correctly by returning it’s own main bundle instead of the bundle of the test target.

以前我们的代码库在 NSBundle 的 +mainBundle 类方法上使用类别覆盖来解决这个问题。但是this is dangerous because the behaviour of overriding an existing method in a category is undefined .

If the name of a method declared in a category is the same as a method in the original class, or a method in another category on the same class (or even a superclass), the behavior is undefined as to which method implementation is used at runtime.

实际上 Xcode 会警告您:

Category is implementing a method which will also be implemented by its primary class

那么，解决这个问题的正确方法是什么？

Answer 1

解决此问题的最简单和最干净的方法是在单元测试中部分模拟 NSBundle 类以在调用 [NSBundle mainBundle 时返回 [NSBundle bundleForClass:[self class]] ]。

你可以把它放在你的 -setup 方法中，这样它就可以为你的整个测试类模拟:

static id _mockNSBundle;

@implementation MyTests

- (void)setUp
{
  [super setUp];

  _mockNSBundle = [OCMockObject niceMockForClass:[NSBundle class]];
  NSBundle *correctMainBundle = [NSBundle bundleForClass:self.class];
  [[[[_mockNSBundle stub] classMethod] andReturn:correctMainBundle] mainBundle];
}

@end

干净整洁。

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