Why is the MOCK_METHOD syntax not working in GMock?

Question

I have not even begun testing and I am encountering some syntax issues with GMock's MOCK_METHOD macro even though I am following GMock's documentation properly. Could it be a compiler issue? I have:

MingGW (GCC 4.9.2)

Googletest 1.10.x

class SimpleClass {

public:
    virtual int simpleFirstFunction(int a, int b) { return (a + simpleSecondFunction(b)); }
    virtual int simpleSecondFunction(int b) { return (2 * b); }
    virtual ~SimpleClass();
};


class MockSimpleClass :public SimpleClass {
    MOCK_METHOD(int, simpleSecondFunction, (int a, int b), (override));
};

I am seeing 3 compiler errors:

Error-1: about the function name

MockSimpleClass.cpp:18:24: error:

'simpleSecondFunction' is not a type MOCK_METHOD(int, simpleSecondFunction(int a, int b), (override));

Error-2: about input parameters

MockSimpleClass.cpp:18:46: error:

expected identifier before '(' token MOCK_METHOD(int, simpleSecondFunction, (int a, int b), (override));

Error-3: About parentheses around "override"

MockSimpleClass.cpp:18:60: error:

expected identifier before '(' token MOCK_METHOD(int, simpleSecondFunction(int a, int b), (override));

Answer 1

MOCK_METHOD macro is not defined. Here is how I troubleshooted the exact same issue:

Check preprocessor: gcc -E s1.cpp > s1.preproc. First of all check the gmock.h included. In my case it was:

72396 # 11 "s1.cpp" 2 72397 # 1 "/usr/include/gmock/gmock.h" 1 3 4

As you can see a system header is included. I wen to check googletest version on system(Ubuntu 19.10): doliaru@host:~/test/gtest/build$ dpkg -l google* rc google-mock:amd64 1.8.1-3 aand using C++ mock classes ii googletest:amd64 1.8.1-3 amd64 Google's C++ test frame dpoliaru@host:~/test/gtest/build$

Apparently this feature was not implemented in 1.8. I cloned the most recent version of googletest here. Having checked the topmost CMakeLists.txt on master branch I see that current gtest version on master is: set(GOOGLETEST_VERSION 1.10.0)

And I built it with these cmake configs:

cmake .. -D CMAKE_INSTALL_PREFIX=/home/dpoliaru/.local/ -D gtest_build_samples=TRUE

After installation, gmock, that I needed for the project was here: /home/dpoliaru/.local/include/gmock/gmock.h

Thus, I updated CMakeLists.txt file of the project with the proper include directory for given target:

... target_include_directories(${PROJECT_NAME} PUBLIC ${GTEST_INCLUDE_DIRS} ${GMOCK_INCLUDE_DIRS}) ...

If you are new to cmake, please check their webpage and find lots of great stuff in cmake-data debian package.

After cmake configure step I see this definition in flags.cmake file:

CXX_INCLUDES = -I/home/dpoliaru/.local/include

With proper include paths I managed to compile the project. Hope that helps.

Answer 2

It sounds like the MOCK_METHOD macro is not defined. Have you set up your include path correctly and added the #include "gmock/gmock.h" directive at the top of your file? You are also missing a public access specifier and the number of arguments is wrong for the function.

This should work if you have the gmock headers on your include path:

#include "gmock/gmock.h"

class SimpleClass {

public:
    virtual int simpleFirstFunction(int a, int b) { return (a + simpleSecondFunction(b)); }
    virtual int simpleSecondFunction(int b) { return (2 * b); }
    virtual ~SimpleClass();
};


class MockSimpleClass : public SimpleClass {
public:
    MOCK_METHOD(int, simpleSecondFunction, (int b), (override));
};