Writing Tests of Asynchronous Operations- Testing with Xcode

XCTest에서 expectation 을 통해 Async Op.을 테스트 할수 있다.
XCTestCase+AsynchronousTesting.h 참조.

// Test that the document is opened. Because opening is asynchronous,

// use XCTestCase's asynchronous APIs to wait until the document has

// finished opening.

- (void)testDocumentOpening

{

// Create an expectation object.

// This test only has one, but it's possible to wait on multiple expectations.

XCTestExpectation *documentOpenExpectation = [self expectationWithDescription:@"document open"];

NSURL *URL = [[NSBundle bundleForClass:[self class]]

URLForResource:@"TestDocument" withExtension:@"mydoc"];

UIDocument *doc = [[UIDocument alloc] initWithFileURL:URL];

[doc openWithCompletionHandler:^(BOOL success) {

XCTAssert(success);

// Possibly assert other things here about the document after it has opened...

// Fulfill the expectation-this will cause -waitForExpectation

// to invoke its completion handler and then return.

[documentOpenExpectation fulfill];

}];

// The test will pause here, running the run loop, until the timeout is hit

// or all expectations are fulfilled.

[self waitForExpectationsWithTimeout:1 handler:^(NSError *error) {

[doc closeWithCompletionHandler:nil];

}];

}