Is MOCK_METHOD* not enough? - googletest

Question

Inspired by that Google doc "ForDummies" :), I am trying a simple Google Mock with Google Test example as follows:
#include <gtest/gtest.h>
#include <gmock/gmock.h>
using ::testing::_;
class A
{
public:
A()
{
std::cout << "A()" << std::endl;
}
virtual ~A()
{
std::cout << "~A()" << std::endl;
}
virtual int incVirtual(int i)
{
return i + 1;
}
};
class MockA: public A
{
public:
MOCK_METHOD1(incVirtual, int(int));
};
TEST(Test, IncTest) {
MockA a;
EXPECT_CALL(a, incVirtual(_));
printf("n == %d\n", a.incVirtual(0));
}
int main(int argc, char **argv)
{
::testing::InitGoogleMock(&argc, argv);
return RUN_ALL_TESTS();
}
When I run it, I get n == 0:
[==========] Running 1 test from 1 test case.
[----------] Global test environment set-up.
[----------] 1 test from Test
[ RUN ] Test.IncTest
A()
n == 0
~A()
whereas I expect it to be n == 1. So I wonder if just defining MOCK_METHODx in the mock class is not enough for mocking the base class method and something additional needs to be done to make MockA::incVirtual call A::incVirtual?

Answer 1

This is behaving the way it should. By mocking your function, the MockA class has essentially overridden the A class implementation with a "do nothing" implementation.
If you want to call A::incVirtual() when calling MockA::incVirtual(), try the following
EXPECT_CALL(a, incVirtual(_)).WillOnce(Invoke(&a, &A::incVirtual));