用抽象类参数模拟类

Question

如果要模拟的类的方法具有抽象的类/接口参数，如何创建模拟？

class DeviceMock : public IDevice
{
    MOCK_METHOD2(AddEngine,
        HRESULT(IEngine* engine, BOOL active));
    MOCK_METHOD2(RemoveEngine,
        HRESULT(IEngine* engine, BOOL active));
}

我收到一条错误消息：

"parameter of abstract class type 'IEngine' is not allowed"

帮助！