A way to exit full app launch mechanics when you're simply invoking the XCTest target and want to speed things up.

AppDelegate.m

#pragma mark - XCTest Support

static BOOL isRunningTests(void) __attribute__((const));

/**
 We need a mechanism to detect if we have been invoked / are running from a unit test.
 If we are, we'll want to exit early instead of doing all kinds of view controller setup.
 This function determines based on the environment, if we're running in a unit test process, 
 such as XCTest.
 */
static BOOL isRunningTests(void)
{
    NSDictionary *environment = [[NSProcessInfo processInfo] environment];
    NSString *injectBundle = environment[@"XCInjectBundle"];
    return [[injectBundle pathExtension] isEqualToString:@"xctest"];
}


#pragma mark - App Lifecycle

- (BOOL)application:(UIApplication *)application willFinishLaunchingWithOptions:(NSDictionary *)launchOptions 
{    
    // If running XCTest unit tests, exit early to get back to the test runner
    if (isRunningTests()) { return YES; }

	// Anything else you might want to do at this stage.

    return YES;
}


- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions 
{
    // If running XCTest unit tests, exit early to get back to the test runner
    if (isRunningTests()) { return YES; }

	// Anything else you might want to do at this stage.
    
    return YES;
}