XCTestの小さなテクニック

    // alternate what setup done

    // full tests in alternated state
    NSArray * tests = [FileLibraryTests testInvocations];
    for (NSInvocation * inv in tests ) {
        NSString * sel = NSStringFromSelector(inv.selector);
        if (![sel containsString:@"WithInit"] && ![sel containsString:@"Monitoring"]) {
            [inv invokeWithTarget:self];
        }
    }

    //back to normal state

    #import <XCTest/XCTestCase+AsynchronousTesting.h>

    dispatch_semaphore_t sema = dispatch_semaphore_create(0);

    dispatch_after(dispatch_time(0, (int64_t)(0.2 * NSEC_PER_SEC)), 
        dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), 
        ^{
            ... dispatch_semaphore_signal(sema); ...
        }
    );

    dispatch_semaphore_wait(sema, dispatch_time(DISPATCH_TIME_NOW, 30*NSEC_PER_SEC));

    XCTestExpectation *expectation = [self expectationWithDescription:@"xxx"];

    // invoke it in code async executing
    ... ^(){
        [expectation fulfill];
    } ...

    [self waitForExpectationsWithTimeout:1 handler:^(NSError *error) {
        // cleanup.
    }];