xcode 5 XCTestCase running not how i expect - iphone

Question

In unit test case I try to make some own logic for my app, like register from another username at current or connect to different servers, without duplicate existing code.
First step that i try to make is a create XCTestCase, alloc class which support for external connections and try to get delegate calls from him.
But NSURLConnection just waiting without network exchange, so i was not success.
Next case, which i try to do is waiting while app will be done and do all issues then:
- (BOOL)waitForCompletion:(NSTimeInterval)timeInterval {
NSDate *timeoutDate =
[NSDate dateWithTimeIntervalSinceNow:timeInterval];
do {
[[NSRunLoop currentRunLoop] runMode:NSDefaultRunLoopMode
beforeDate:timeoutDate];
if([timeoutDate timeIntervalSinceNow] < 0.0) {
break;
}
} while (self.hasOperationFinishedPerforming == NO);
return self.hasOperationFinishedPerforming;
}
But in that case, app starting, do all current cycle, but i have no idea, how i can detect from current app code that there is running unit tests. I tried to set preprocessor macros on unit test target's but it not effected in code inside app, only effect on code of tests classes as well.
Any ideas?

Answer 1

Assuming you have set your unit test target's Bundle Loader build setting to use your app, you can determine if your app is running as part your unit tests like so:
static BOOL isRunningTests(void)
{
NSDictionary* environment = [[NSProcessInfo processInfo] environment];
NSString* injectBundle = environment[#"XCInjectBundle"];
return [[injectBundle pathExtension] isEqualToString:#"octest"]; // For SenTestKit; use "xctest" for XCTest
}
- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {
if (isRunningTests())
return YES;
// Normal app launch stuff here...
...
}
That being said, your unit tests should not be testing anything that relies on external services, like APIs or databases, being available. If you cannot avoid having those kinds of things available, then you should look at "mock" objects (using 3rd party libraries like OCMock) which let you stub out complex classes and control what they return within your test environment.
The purpose of unit testing is NOT to test someone else's API or database or SDK, but rather to test your code and algorithms. If you can't test your code this way, that may be a signal that you need to refactor your code into more testable chunks.
There is a great book titled "Test-Driven iOS Development" by Graham Lee which I highly recommend that talks all about writing unit tests for iOS projects.

Answer 2

When you try to test a NSURLConnection which implements delegates, you need to take care to correctly implement the run loop related code.
Your waitForCompletion: method will likely not work or be unreliable. The reason is, method runMode:beforeDate: will not return until after an "event" has been executed in mode :NSDefaultRunLoopMode - or the timeout is expired. An event originates from some "run loop source" and ends up being a method which gets called. The NSURLConnection for example is such a "run loop source" since it schedules delegate methods which are "events" that get eventually executed by the target run loop for the specified mode.
Now, you loop until self.hasOperationFinishedPerforming == NO. The flag may be eventually set, and you may expect the run loop will return and check the flag. But this is not the case until after some arbitrary event has been scheduled afterwards to the run loop with the specified mode. Only then (unless expired), the runMode:beforeDate: returns and finally checks the flag.
In order to cause the run loop return immediately, you may send a dummy event in your completion handler, or wherever it's appropriate when signaling an asynchronous completion:
self.hasOperationFinishedPerforming == YES;
[#"" performSelector:#selector(self) onThread:thread
withObject:nil
waitUntilDone:NO];
This however, WILL indeed require the completion handler to know that it will execute in the testing environment.
There are solutions to avoid this completely, but will require third party libs.