ObjCExp1Tests.m

#import <UIKit/UIKit.h>
#import <XCTest/XCTest.h>

@interface ObjCExp1Tests : XCTestCase

@end

@implementation ObjCExp1Tests

- (void)setUp {
    [super setUp];
    // Put setup code here. This method is called before the invocation of each test method in the class.
}

- (void)tearDown {
    // Put teardown code here. This method is called after the invocation of each test method in the class.
    [super tearDown];
}

// test doesn't fail.
- (void)testFail1 {
    __block BOOL called = NO;
    dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{
        XCTFail("failed");
        called = YES;
    });
    [NSThread sleepForTimeInterval:3];
    XCTAssertTrue(called, "called");
}

// test does fail as expected.
- (void)testFail2 {
    XCTestExpectation *expectation = [self expectationWithDescription:@"fail2"];
    dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{
        XCTFail("failed");
        [expectation fulfill];
    });
    [self waitForExpectationsWithTimeout:5.0 handler:nil];
}

@end