CPP FakeIt library multiple inheritence

Question

I'm comparing GoogleMock vs FakeIt for writing unit tests. I like FakeIt over GoogleMock because I'm from Java background and FakeIt sticks close to Mockito/JMock syntax which make using the library much easier to write & maintain.

But FakeIt GIT home (https://github.com/eranpeer/FakeIt) says it doesn't support MultipleInheritance and the application im testing has code with multiple inheritance. I dont have to support diamond inheritance, so I would like to know if its just that aspect of multiple inheritance thats not supported or are there other aspects thats not supported as well?

Answer 1

Unfortunately it seems that any type of multiple inheritance is not supported, even if it's just an "interface" that unifies several other "interfaces", e.g.:

struct IA { virtual void a() = 0; };
struct IB { virtual void b() = 0; };
struct IC : public IA, public IB {};
fakeit::Mock<IC> mock; // error :(

(The check is done using std::is_simple_inheritance_layout<T>)

I did, however, find a little workaround for this problem, at least for simple scenarios:

class MockC : public IC {
public:
    MockC(IA& a, IB& b) : m_a(a), m_b(b) {}
    void a() override { return m_a.a(); };
    void b() override { return m_b.b(); };
private:
    IA& m_a;
    IB& m_b;
};

fakeit::Mock<IA> mockA;
fakeit::Mock<IB> mockB;
MockC mockC(mockA.get(), mockB.get());
// Use mockA and mockB to set up the mock behavior the way you want it.
// Just make sure not to use mockC after they go out of scope!