Can Google Mock a method with a smart pointer return type?
c++, googlemock, smart-pointers, unit-testing
Solution
Google Mock requires parameters and return values of mocked methods to be copyable, in most cases. Per boost's documentation, unique_ptr is not copyable. You have an option of returning one of the smart pointer classes that use shared ownership (shared_ptr, linked_ptr, etc.) and are thus copyable. Or you can use a raw pointer. Since the method in question is apparently the method constructing an object, I see no inherent problem with returning a raw pointer. As long as you assign the result to some shared pointer at every call site, you are going to be fine.
Problem
I have a factory that returns a smart pointer. Regardless of what smart pointer I use, I can't get Google Mock to mock the factory method. The mock object is the implementation of a pure abstract interface where all methods are virtual. I have a prototype: ``` MOCK_METHOD0(Create, std::unique_ptr<IMyObjectThing>()); ``` And I get: ``` "...gmock/gmock-spec-builders.h(1314): error C2248: 'std::unique_ptr<_Ty>::unique_ptr' : cannot access private member declared in class 'std::unique_ptr<_Ty>'" ``` The type pointed to in the smart pointer is defined. And I get it's trying to access one of the constructors declared private, but I don't understand why. When this was an std::auto_ptr, the error said there was no copy constructor, which confuses me. Anyway, is there a way to Mock a method that returns a smart pointer? Or is there a better way to build a factory? Is my only resolve to return a raw pointer (blech...)? My environment is Visual Studio 2010 Ultimate and Windows 7. I'm not using CLI.