CMake For Google Tests When Class Definitions Are In .CPP

Question

When my class definitions are inside my .h files, my make command did not give any errors and my tests were passing successfully.

However, as soon as I move the class definitions to .cpp files, I get an undefined reference to `Class::method(int)' for everything. How should I change my CMakeLists.txt accordingly?

CMakeLists.txt

cmake_minimum_required(VERSION 2.6)

# Locate GTest
find_package(GTest REQUIRED)
include_directories(${GTEST_INCLUDE_DIRS})

# Link runTests with what we want to test and the GTest and pthread library
add_executable(runTests tests.cpp)
target_link_libraries(runTests ${GTEST_LIBRARIES} ${GTEST_MAIN_LIBRARIES} pthread)

I have followed this tutorial:

https://www.eriksmistad.no/getting-started-with-google-test-on-ubuntu/

Example. Instructor.h

#ifndef INSTRUCTOR_H
#define INSTRUCTOR_H

#include <iostream>
#include <vector>
using namespace std;

class Instructor
{
    int instrId;
    string instrEmail;
    string instrPassword;

public:
    Instructor();
    void showGameStatus();
    void setInstrId(int newInstrId);
    int getInstrId();

};

#endif

Instructor.cpp

#include <iostream>
#include "Instructor.h"
using namespace std;

Instructor::Instructor()
{
    cout << " Default Instructor Constructor\n";
    instrId = 0;
    instrEmail = "@jaocbs-university.de";
    instrPassword = "123";
}
void Instructor::setInstrId(const int newInstrId)
{
     instrId = newInstrId;
}

int Instructor::getInstrId()
{
    return instrId;
}

Answer 1

If you're getting "undefined reference" of that sort make sure you're linking in the result of compiling Instructor.cpp, or that Instructor.cpp is a dependency of the test depending on how your build is organized.

This may be as simple as:

add_executable(runTests tests.cpp Instructor.cpp)

Though that may need to be adjusted based on the specifics of your path.