gistfile1.m

#ifdef DEBUG
/// Tests if .xctest bundle is loaded, so returns YES if the app is running with XCTest framework.
inline BOOL IsUnitTesting() __attribute__((const));
inline BOOL IsUnitTesting()
{
    NSDictionary *environment = [NSProcessInfo processInfo].environment;
    NSString *injectBundlePath = environment[@"XCInjectBundle"];
    return [injectBundlePath.pathExtension isEqualToString:@"xctest"];
}
#endif

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{
    
#ifdef DEBUG
    if (IsUnitTesting()) return YES;
#endif
    // ...
}