FPrime and Google Mock

[weggert2]

TLDR: Is it possible to have the component member variable of GTestBase classes be a pointer instead of an object?

Hello, I would like to mock out my components, for use with Google Mock. This is so I can test that something is called versus what calling something does. Very useful for things that do system calls, IO, or other things that are hard to control in a unit test environment.

However, the "GTestBase" autocoded classes make this hard. A Tester class needs to look like

class MyComponentTester : public MyComponentGTestBase
{
public:
    MyComponent component;
};

To have this be mockable, you need to be able to replace component with something else, which needs a pointer:

class MyComponentTester : public MyComponentTestBase
{
public:
    void setComponent(Component *newComponent) { component = newComponent; }

    MyComponent *component;
};

And then with google mock you can do:

class MockMyComponent : public MyComponent
{
public:
    MOCK_METHOD(void, someMethod, (int arg1, int arg2), (override));
};

Which allows you to write tests like

#include <gmock/gmock.h>
#include "MyComponent.hpp"

using ::testing::_;

TEST(MyComponent, someMethodIsCalled)
{
     MyComponentTester tester;
     MockMyComponent component;
     tester.setComponent(&tester);

     EXPECT_CALL(component, someMethod(_, _).Times(1)

     tester.RunMyTest();
}

Very, very handy for testing that your component does what you think it's going to do, without worrying about side effects. Is this achievable with the current GTestBase pattern?

[weggert2]

@zimri-leisher is teaching me how to use ports to mimic the same behavior, using the invoke_to pattern. Very interesting!