CODEWITHSUNDEEP
c++googlemock
aminator
aminator

Reputation: 491

Google Mock: passing pointer to mock object, but method call is still calling real method

i have this simple code

struct SimpleStruct {
    int add(int a, int b) {
        return a+b;
    }
};

class SimpleClass {
public:
    int SimpleMethod(SimpleStruct* simpleStruct, int a, int b) {
        return simpleStruct->add(a, b);
    }
};

Now I would like to test the SimpleMethod and mock the SimpleStruct like this:

struct MockSimpleStruct : public SimpleStruct {
    MOCK_METHOD(int, add, (int, int), (const));
};


TEST(Test_Calculation, simpleStruct) {
    MockSimpleStruct mockSimpleStruct;

    EXPECT_CALL(mockSimpleStruct, add(_,_)).Times(2).WillOnce(DoAll(Return(7))).WillOnce(DoAll(Return(7)));
    EXPECT_EQ(7, mockSimpleStruct.add(2, 3)); // working fine

    SimpleClass simpleClass;
    int result = simpleClass.SimpleMethod(&mockSimpleStruct, 2, 3); // not working: inside SimpleMethod the real add method is called

    EXPECT_EQ(7, result); // fails
}

How can I assure that the mocked method is being used?

My question is related to this Question, but I cannot change the use of SimpleStruct in the signature of SimpleMethod, because in my case my signature is defined through the jni.

Upvotes: 0

Views: 1335

Answers (1)

sklott
sklott

Reputation: 2859

Gmock can mock only virtual functions, so in order for it to work add() should be declared virtual. But it only necessary for it to be virtual for unit testing, so you can do something like:

#ifdef UNDER_TEST
#define TEST_VIRTUAL virtual
#else
#define TEST_VIRTUAL
#endif

struct SimpleStruct {
    TEST_VIRTUAL int add(int a, int b) {
        return a+b;
    }
};

Just make sure that tested code doesn't depend from fact that SimpleStruct is POD.

Upvotes: 1

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