Example asynchronous GHUnit test.

AsyncTest.h

#import <SenTestingKit/SenTestingKit.h>

@interface AsyncTests : SenTestCase {
	NSCondition* condition;
	BOOL operationSucceeded;
}

@end

AsyncTests.m

#import "AsyncTests.h"

@implementation AsyncTests

- (void) setUp
{
	condition = [[NSCondition alloc] init];
	operationSucceeded = NO;
}

- (void) tearDown
{
	[condition release];
}

- (void) testAsynchronousMethodCall
{
	// Create and start an asynchronous operation
	NSOperationQueue* queue = [[[NSOperationQueue alloc] init] autorelease];
	MyOperation* operation = [[[MyOperation alloc] init] autorelease];
	[queue addOperation:operation];
	
	// Block and wait for one of the delegate methods to be called
	[condition lock];
	[condition wait];
	[condition unlock];
	
	// Our operation has completed at this point, so we can check if it was successful
	STAssertTrue(operationSucceeded, @"");
}

- (void) myOperationDidFinish
{
	operationSucceeded = YES;
	
	[condition lock];
	[condition signal];
	[condition unlock];
}

- (void) myOperationDidFailWithError:(NSError*)error
{
	operationSucceeded = NO;
	
	[condition lock];
	[condition signal];
	[condition unlock];
}

@end

To solve the problem where neither delegate method is called, you could replace -wait with -waitUntilDate:

NSDate *date = [[NSDate date] dateByAddingTimeInterval:10];
[condition lock];
BOOL timedOut = ![self.condition waitUntilDate:date];
[self.condition unlock];

if (timedOut) {
  // do something
} else {
    GHAssertTrue(self.operationSucceeded, nil);
}

I encountered this problem when testing async code on the command line. Specifically, I was testing the outcome of an ASIHTTRequest. On the command line, my asynchronous tests were hanging so I implemented the 10 sec timeout with -waitUntilDate:. Unfortunately, I have not discovered the root of the problem: why are the async tests hanging on the command line?

OCUnit / SenTesting framework does not run within the normal RunLoop; which NSURLConnection relies on to execute. This is why the request never starts and none of the delegate methods are ever called. I tried to make this work in OCUnit for some time (including manually 'spinning' the RunLoop) with no success. The simplest/best alternative is using another test framework which does run tests in full application mode. I recommend GHUnit for ease of use; it's quick to set up and there are plenty of examples online.