用AVCaptureDevice模拟OCMock

Question

我正在尝试为我为AVCaptureVideoPreviewLayer实现的点击到焦点方法编写测试。我想使用模拟AVCaptureDevice来传递各种条件，然后确保调用预期的方法来处理实际的聚焦。下面是我正在使用的代码。

NSArray *devices = [AVCaptureDevice devices];

for (AVCaptureDevice *device in devices)
{
    if ([device hasMediaType:AVMediaTypeVideo])
    {
        if ([device position] == AVCaptureDevicePositionBack)
        {
            CGPoint point = CGPointMake(focus_y, 1-focus_x);

            if ([device isFocusModeSupported:AVCaptureFocusModeContinuousAutoFocus] && [device lockForConfiguration:&error])
            {
            ...

这是我到目前为止拥有的测试代码：

id deviceMock = [OCMockObject niceMockForClass:[AVCaptureDevice class]];
[[[deviceMock stub] andReturnValue:@YES] hasMediaType:AVMediaTypeVideo];
[(AVCaptureDevice*)[[deviceMock stub] andReturnValue:@(AVCaptureDevicePositionBack)] position];
[[[deviceMock stub] andReturnValue:@YES] isFocusModeSupported:AVCaptureFocusModeContinuousAutoFocus];
[[[deviceMock stub] andReturnValue:@YES] lockForConfiguration:nil];

[[deviceMock expect] setFocusPointOfInterest:CGPointZero];
[[deviceMock expect] setFocusMode:AVCaptureFocusModeAutoFocus];
[[deviceMock expect] unlockForConfiguration];
[self waitForCompletion:0.55]; //Wait for UI animation
[deviceMock verify]

我想做三个测试：

• AVCaptureDevice设备返回0台设备，但什么也不会发生
• AVCaptureDevice设备返回不兼容的设备，什么都不会发生。
• AVCaptureDevice设备返回一个兼容的设备，上面的测试代码通过。

因此，我想我的问题归结为有一个简单的方法来存根和返回[AVCaptureDevice devices]类方法吗？还是假设iPhone/iPad上只能有一个通过上述条件的iPhone/iPad，以便将设备存储为属性并重写正在测试的方法，以便注入模拟AVCaptureDevice？

Answer 1

您可以对类方法“设备”进行存根，以返回包含所选内容的数组。

id deviceMock = [OCMockObject niceMockForClass:[AVCaptureDevice class]];

// I think you need to change your return value code to this for the booleans:
[[[deviceMock stub] andReturnValue:OCMOCK_VALUE((BOOL){YES})] hasMediaType:AVMediaTypeVideo];
[[[deviceMock stub] andReturnValue:OCMOCK_VALUE((BOOL){YES})] isFocusModeSupported:AVCaptureFocusModeContinuousAutoFocus];
[[[deviceMock stub] andReturnValue:OCMOCK_VALUE((BOOL){YES})] lockForConfiguration:nil];

// No need to wrap the position in an NSNumber
[(AVCaptureDevice*)[[deviceMock stub] andReturnValue:AVCaptureDevicePositionBack] position];

// Stub the class method that returns the devices array
[[[deviceMock stub] andReturn:@[ deviceMock ]] devices];

[[deviceMock expect] setFocusPointOfInterest:CGPointZero];
[[deviceMock expect] setFocusMode:AVCaptureFocusModeAutoFocus];
[[deviceMock expect] unlockForConfiguration];
[self waitForCompletion:0.55]; //Wait for UI animation
[deviceMock verify]

我想这应该会让你上路的。