bonobomock

Mock Static Function

In this example we are going to show you how to mock and test a static function using BonoboMock.

Note: In optimized builds (e.g., CMake build types RelWithDebInfo or Release), the compiler may inline functions, preventing BonoboMock from intercepting calls. See Function inlining for this limitation and the available mitigations using the optimization macros and CMake helper.

Note: If your project uses C++03, auto is unavailable. Explicitly declare the mock type instead — see Explicit Mock Object Types.

Define static function

Let’s define a static function sample_function in class SampleClass, it takes a boolean argument and returns the boolean value:

class SampleClass {
public:
    static bool sample_function(bool in) {
        return in;
    }
};

Write unittest using BonoboMock

TEST(Static, Mock) {
    // Mock static function sample_function in class SampleClass
#ifdef BSLS_COMPILERFEATURES_FULL_CPP11
    auto mock = BONOBO_MOCK(&SampleClass::sample_function);
#else
    bsl::shared_ptr<GMock<bool(bool)> > mock = BONOBO_MOCK(&SampleClass::sample_function);
#endif

    EXPECT_CALL(*mock, BONOBO_MOCK_FUNCTION(false))
        .Times(1)
        .WillOnce(Return(true));

    EXPECT_TRUE(SampleClass::sample_function(false));

    EXPECT_CALL(*mock, BONOBO_MOCK_FUNCTION(_))
        .WillRepeatedly(Return(true));

    EXPECT_TRUE(SampleClass::sample_function(false));
    EXPECT_TRUE(SampleClass::sample_function(true));

    mock->restore();

    EXPECT_FALSE(SampleClass::sample_function(false));
    EXPECT_TRUE(SampleClass::sample_function(true));
}

For sample_function, we first pass the address of it to BONOBO_MOCK, which will return a mock object that manages the mocking. After creating the mock object, we can define how we expect it to behave using BONOBO_MOCK_FUNCTION. Because sample_function takes 1 boolean argument, we can match the matcher parameter to a specific argument or match anything using _. In this example, the first EXPECT_CALL is mocking the specific case in which sample_function is called with false as input. The second EXPECT_CALL is to mock all other cases.

If you need to stop mocking in the middle of the unit test, you can use mock->restore() to revert to the default behavior.

The mock object will automatically restore the mocking when it goes out of scope.

Example source code

You can find additional examples among the unit test files for the library under tests/unit/.

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