How to mock const& methods with gmock

Question

If I have:

class Foo
{
public:
virtual int Duplicate(int) const& = 0;
};

How can I define a mock object with gMock inheriting from Foo and mocking the Duplicate method?

I have tried:

class MockFoo : public Foo
{
public:
    MOCK_METHOD(int, Duplicate, (int), (const&, override));
};

but it doesn't work, do you have any suggestions?

Answer 1

At least from v1.12.x, from gmock_cook_book, use ref(&), so

class MockFoo : public Foo
{
public:
    MOCK_METHOD(int, Duplicate, (int), (const, ref(&), override));
};

Demo

For v1.10.0, there is still a workaround with indirection:

class MockFoo : public Foo
{
public:
    MOCK_METHOD(int, DuplicateRef, (int), (const));
    int Duplicate(int n) const& override { return DuplicateRef(n); }
};

Demo