unit test case for a asynchronous method ios

Question

i am new in the ios line. I have a task to crete test case for this method.

+ (void)myMethod:(NSString *)paramA callback:(void(^)(NSString *result, BOOL success))callback;
// ... Some code that runs async (for example, something that fetches data from the internet)...

// Call the callback function in a background thread
dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{
    callback(@"Success", YES);
});
}

As through rnd i get to kno something related to XCTestExpectation used to create unit test cases....

Answer 1

Just call fulfill in the compeletion block. For example:

Assume the FunctionObj holds the function

@interface FunctionObj : NSObject
+ (void)myMethod:(NSString *)paramA callback:(void(^)(NSString *result, BOOL success))callback;
@end
@implementation FunctionObj
+ (void)myMethod:(NSString *)paramA callback:(void(^)(NSString *result, BOOL success))callback {

    dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{
    callback(@"Success", YES);
    });
}
@end

Then the test case should be

- (void)testAsyncFunction {
    XCTestExpectation * expectation = [self expectationWithDescription:@"Test async method"];
    [FunctionObj myMethod:@"1" callback:^(NSString *result, BOOL success) {
        XCTAssert(success,"should be succeed");
        XCTAssertNotNil(result,@"Should not be nil");
        [expectation fulfill];
    }];
    [self waitForExpectationsWithTimeout:10 handler:^(NSError *error) {
        //Do something when time out
    }];
}