CMake + GoogleTest + gcov

This little repo should contain everything you need to know if you want to:

• Structure a C++ project with CMake.
• Run tests for your code through GoogleTest.
• Check code coverage by means of gcov.

As an example, the file build-and-run-cov.sh will:

• Build your code with coverageflags (-fprofile-arcs -ftest-coverage ).
• Run all the tests.
• Show coverage information.

In this case our code consists of a simple shared library.

library.cpp

#include "library.h"

#include <iostream>

void foo(){
    std::cout << "Foo!" << std::endl;
}

void bar(int n){
    if (n > 0){
        std::cout << "n is greater than 0!" << std::endl;
    }
    else if (n < 0){
        std::cout << "n is less than 0!" << std::endl;
    }
    else{
        stad::cout << "n is exactly 0!" << std::endl;
    }
}

void baz(){  // LCOV_EXCL_START
    std::cout << "Baz!" << std::endl;
}
// LCOV_EXCL_STOP

And our tests are:

test_library.h

#include "../src/library.h"

#include <gtest/gtest.h>


namespace cpp_project_template::tests {
    TEST(TestFooSuite,TestFoo){
        foo();
    }
    TEST(TestBarSuite,TestBarGreaterThanZero){
        bar(100);
    }
    TEST(TestBarSuite,TestBarEqualToZero){
        bar(0);
    }
    TEST(TestBarSuite,TestBarLessThanZero){
        bar(-100);
    }
}

The generated lcov report will be:

Dependencies

lcov

Ubuntu

sudo apt update && sudo apt install lcov

MacOs

brew install lcov

Compiling with GCC

On Ubuntu

Just run

./build-and-run-cov.sh

On MacOs:

You can install gcc with home-brew by running brew install gcc.

Then you just have to specify the environment variables CC, CXX, and GCOV before building.

CC=/usr/local/bin/gcc-11 CXX=/usr/local/bin/g++-11 GCOV=/usr/local/bin/gcov-11 ./build-and-run-cov.sh

(Check your gccversion under /usr/local/bin/ first)

Compiling with CLang

On MacOs

The default compiler on MacOs is AppleClang (even if you try to use the gcc command it will actually run clang, see here or just run gcc --version for confirmation)

The default options will work just fine:

./build-and-run-cov.sh

On Ubuntu

You can install CLang by following these instructions. As explained in the GCC section, you just have to specify the CC, CXX, and GCOV variables.

$ CC=clang-13 CXX=clang++-13 GCOV=$PWD/llvm-cov-13.sh ./build-and-run-cov.sh

Where llvm-cov-13.sh is a wrapper for llvm-cov-13 for compatibility with the --gcov-tool flag (see this for more detail).

#!/bin/bash
exec llvm-cov-13 gcov "$@"

Note: don't forget to make the file executable! (chmod 755 llvm-cov-13.sh )

Compiling on Windows

... one day ...