Call "waitForCompletion" after invoking an async method. Upon receiving notification, set "executionDate" to YES and call [runloopExpirationTimer fire]. This will "dry up" the fake run loop.

XCTestAsync.mm

- (void)waitForCompletion {
  runloopExpirationTimer = [NSTimer scheduledTimerWithTimeInterval:600.0 target:self selector:@selector(dumbTimerMethod:) userInfo:nil repeats:NO];
	while ( !executionDone ) {
		[[NSRunLoop currentRunLoop] runMode:NSDefaultRunLoopMode beforeDate:[NSDate distantFuture]];
	}
}

- (void)dumbTimerMethod:(NSTimer *)theTimer {
	runloopExpirationTimer = nil;
}