OperationSchedulerTests-1.m

- (void)testThatAuthOperationBlocksGeneralOperations {
    // given
    XCTestExpectation *expectation = [self expectationWithDescription:@"Last operation fired"];
    NSMutableArray *operationNames = [NSMutableArray array];

    NSString *const kAuthOperationName = @"AuthOperation";
    NSString *const kInitialOperationName = @"InitialOperation";
    NSString *const kGeneralOperationName = @"GeneralOperation";
    NSUInteger const kGeneralOperationsCount = 5;
    __block NSNumber *operationCounter = @0;

    NSBlockOperation *authOperation = [NSBlockOperation blockOperationWithBlock:^{
        dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{
            @synchronized(operationNames) {
                [operationNames addObject:kAuthOperationName];
            }
            [NSThread sleepForTimeInterval:0.05];
        });
    }];


    NSBlockOperation *initialOperation = [NSBlockOperation blockOperationWithBlock:^{
        @synchronized(operationNames) {
            [operationNames addObject:kInitialOperationName];
        }
        [self.scheduler addAuthOperation:authOperation];
    }];

    // when
    [self.scheduler addGeneralOperation:initialOperation];
    for (NSUInteger i = 0; i < kGeneralOperationsCount; i++) {
        NSBlockOperation *generalOperation = [NSBlockOperation blockOperationWithBlock:^{
            @synchronized(operationNames) {
                [operationNames addObject:kGeneralOperationName];
            }

            @synchronized(operationCounter) {
                operationCounter = @([operationCounter integerValue] + 1);
                if ([operationCounter integerValue] == kGeneralOperationsCount) {
                    dispatch_async(dispatch_get_main_queue(), ^{
                        [expectation fulfill];
                    });
                }
            }
        }];
        [self.scheduler addGeneralOperation:generalOperation];
    }

    // then
    [self waitForExpectationsWithTimeout:kTestExpectationTimeout handler:^(NSError *error) {
        XCTAssertEqualObjects(operationNames[0], kInitialOperationName);
        XCTAssertEqualObjects(operationNames[1], kAuthOperationName);
        for (NSUInteger i = 2; i < kGeneralOperationsCount; i++) {
            XCTAssertEqualObjects(operationNames[i], kGeneralOperationName);
        }
    }];
}

OperationSchedulerTests-2.m

- (void)testThatAuthOperationBlocksGeneralOperations {
    // given
    NSUInteger const kGeneralOperationsCount = 5;
    TestBlockingByAuthOperationEnvironment *environment = [TestBlockingByAuthOperationEnvironment new];
    [environment setupEnvironmentWithTestCase:self
                       generalOperationsCount:kGeneralOperationsCount
                        initialOperationBlock:^{
        [self.scheduler addAuthOperation:environment.authOperation];

        for (NSOperation *operation in environment.generalOperations) {
            [self.scheduler addGeneralOperation:operation];
        }
    }];

    // when
    [self.scheduler addGeneralOperation:environment.initialOperation];

    // then
    [self waitForExpectationsWithTimeout:kTestExpectationTimeout handler:^(NSError *error) {
        XCTAssertEqualObjects(environment.firedOperationNames[0], kInitialOperationName);
        XCTAssertEqualObjects(environment.firedOperationNames[1], kAuthOperationName);
        for (NSUInteger i = 2; i < kGeneralOperationsCount; i++) {
            XCTAssertEqualObjects(environment.firedOperationNames[i], kGeneralOperationName);
        }
    }];
}