使用动画进行iOS单元测试

Question

为什么使用Xcode 5.0和XCTesting进行以下单元测试？我的意思是，我理解底线：1 == 0未评估。但为什么不进行评估呢？如何才能使其失败？

- (void)testAnimationResult
{
    [UIView animateWithDuration:1.5 animations:^{
        // Some animation
    } completion:^(BOOL finished) {
        XCTAssertTrue(1 == 0, @"Error: 1 does not equal 0, of course!");
    }];
}

Answer 1

从技术上讲，这将起作用。但当然测试将持续2秒。如果你有几千个测试，这可以加起来。

更有效的是在类别中存根UIView静态方法，以便它立即生效。然后在测试目标中包含该文件（但不包括您的应用程序目标），以便仅将类别编译到测试中。我们用：

#import "UIView+Spec.h"

@implementation UIView (Spec)

#pragma mark - Animation
+ (void)animateWithDuration:(NSTimeInterval)duration animations:(void (^)(void))animations completion:(void (^)(BOOL finished))completion {
    if (animations) {
        animations();
    }
    if (completion) {
        completion(YES);
    }
}

@end

上面只是立即执行动画块，如果也提供了立即完成块。

Answer 2

@dasblinkenlight走在正确的轨道上;这是我为使其正常工作所做的：

- (void)testAnimationResult
{
    [UIView animateWithDuration:1.5 animations:^{
        // Some animation
    } completion:^(BOOL finished) {
        XCTAssertTrue(1 == 0, @"Error: 1 does not equal 0, of course!");
    }];

    [[NSRunLoop currentRunLoop] runUntilDate:[NSDate dateWithTimeIntervalSinceNow:2.0]];
}

Answer 3

这里的目标是将异步操作转换为同步操作。最常用的方法是使用信号量。

- (void)testAnimationResult {
    // Create a semaphore object
    dispatch_semaphore_t sem = dispatch_semaphore_create(0);

    [UIView animateWithDuration:1.5 animations:^{
        // Some animation
    } completion:^(BOOL finished) {
       // Signal the operation is complete
       dispatch_semaphore_signal(sem);
    }];

    // Wait for the operation to complete, but not forever
    double delayInSeconds = 5.0;  // How long until it's too long?
    dispatch_time_t timeout = dispatch_time(DISPATCH_TIME_NOW, (int64_t)(delayInSeconds * NSEC_PER_SEC));
    long timeoutResult = dispatch_semaphore_wait(sem, timeout);

    // Perform any tests (these could also go in the completion block, 
    // but it's usually clearer to put them here.
    XCTAssertTrue(timeoutResult == 0, @"Semaphore timed out without completing.");
    XCTAssertTrue(1 == 0, @"Error: 1 does not equal 0, of course!");
}

如果你想看一些这方面的例子，请看RNCryptorTests。

Answer 4

更好的方法（现在）是使用期望。

func testAnimationResult() {
    let exp = expectation(description: "Wait for animation")

    UIView.animate(withDuration: 0.5, animations: {
        // Some animation
    }) { finished in
        XCTAssertTrue(1 == 0)
        exp.fulfill()
    }

    waitForExpectations(timeout: 1.0, handler: nil)
}