Passing arguments to ReturnNew with googlemock

Question

How can I mock a method that returns a new object whose constructor takes one of the method's arguments as an argument of its own?

// ObjectA::ObjectA(MockedObject arg1, ObjectB* arg2);
// ObjectA* MockedObject::MockedMethod(ObjectB* arg);
ON_CALL(mocked_object, MockedMethod(_))
    .WillByDefault(ReturnNew<ObjectA>(mocked_object, new ObjectB()));

In the above example, rather than using new ObjectB() as the argument for ReturnNew<ObjectA>(), I would like to use the _ argument originally passed to MockedMethod.

Answer 1

I'd just use WithArg and Invoke with a lambda rather than ReturnNew in this case:

ON_CALL(mocked_object, MockedMethod(_))
    .WillByDefault(WithArg<0>(Invoke(
        [&mocked_object](ObjectB* b) { return new ObjectA(&mocked_object, b); })));