ios - 使用 OCMock 模拟 AVCaptureDevice

Question

我正在尝试为我为 AVCaptureVideoPreviewLayer 实现的点击聚焦方法编写测试。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])
            {
            ...

这是我目前的测试代码:

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]

我想进行三个测试:

• [AVCaptureDevice devices] 返回 0 个设备并且没有任何反应
• [AVCaptureDevice 设备] 返回一个不兼容的设备并且没有任何反应
• [AVCaptureDevice devices] 返回一个兼容的设备，上面的测试代码通过

所以我想我的问题归结为是否有一种简单的方法来 stub 并返回 [AVCaptureDevice devices] 类方法？或者可以安全地假设 iPhone/iPad 上只能有一个 AVCaptureDevice 通过上述条件，所以我可以将设备存储为属性并重写方法我正在测试以便可以注入(inject)模拟 AVCaptureDevice?

Answer 1

您可以 stub 类方法“devices”以返回包含您选择的内容的数组。

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]

我认为这应该可以让您继续前进。