Testing NSNotification in Kiwi iOS

So I need to test whether a NSNotification is posted. I tried the following code to spy on the argument.

[[NSNotificationCenter defaultCenter] stub:@selector(postNotification:)];

__block KWCaptureSpy *notificationSpy = [[NSNotificationCenter 
defaultCenter] captureArgument:@selector(postNotification:) atIndex:0];

[[theValue(notificationSpy.argument.name) should] equal:theValue(SOME_NOTIFICATION)];

but the problem with this is the since it's asynchronous the argument is not always captured before testing. I can't add shouldEventually for notificationSpy.argument.name either as it throws NSInternalConsistencyException for accessing the argument before capturing.

I also tried, [[SOME_NOTIFICATION should] bePosted]; and it failed as well.

You can use expectFutureValue() if you expect the notification to be sent sometime in the future:

[[expectFutureValue(((NSNotification*)notificationSpy.argument).name) shouldEventually] equal:@"MyNotification"];

You also won't get the NSInternalConsistencyException exception, as Kiwi seems to work fine with spies not yet resolved, if wrapped inside a expectFutureValue.

Other alternatives would be to

• stub the sendNotification: method and "manually" capture the sent notification:

  __block NSString *notifName = nil;
  [[NSNotificationCenter defaultCenter] stub:@selector(postNotification:) withBlock:^id(NSArray *params) {
      NSNotification *notification = params[0];
      notifName = notification.name;
      return nil;
  }];
  [[notifName shouldEventually] equal:@"TestNotification"];
  

• write a custom matcher that registers to the notification center and assert on that matcher:

  [[[NSNotificationCenter defaultCenter] shouldEventually] sendNotification:@"MyNotification"]];
  

Personally, I'd go with the custom matcher approach, it's more elegant and more flexible.