How to install googletest library?

2 minute read

Setting up googletest (or gtest, C++ unit testing library) can be tricky. When starting a new project, integrating googletest can be problematic, despite having no such issues with other libraries.

The following guide provides instructions on how to compile and add googletest to a C++ project. It uses pkg-config to obtain compiler flags and works with build systems such as cmake.

It was tested on Ubuntu but might work on other systems as well.

Download and compile googletest

Download the latest release from https://github.com/google/googletest/releases

1wget https://github.com/google/googletest/archive/release-1.8.0.tar.gz

and extract it:

1tar xzf release-1.8.0.tar.gz
2cd googletest-release-1.8.0

After that, we can compile it:

1mkdir build && cd build
2cmake ..
3make -j

Now, copy the headers to a directory where compilers can find them:

1sudo cp -r ../googletest/include /usr/local/include

Then, copy static libraries:

1sudo cp -r ./googlemock/gtest/libgtest*.a /usr/local/lib/

Additionally, you can also add googlemock library (C++ framework for mocking objects):

1sudo cp -r ./googlemock/libgmock*.a /usr/local/lib/

Find googletest with pkg-config

After compiling and installing library files, try to find the library with pkg-config:

1pkg-config --libs --cflags gtest

If you get a message about gtest not being found (“Package gtest was not found in the pkg-config search path”) then it means pkg-config cannot find gtest’s .pc file which provides the necessary configuration.

Run the following command to see the list of directories read by pkg-config:

1pkg-config --variable pc_path pkg-config

Choose one of them, e.g. /usr/lib/pkgconfig, and inside that directory create a file named gtest.pc which should like similar to this:

 1prefix=/usr/local
 2exec_prefix=${prefix}
 3libdir=${prefix}/lib
 4includedir=${prefix}/include
 5
 6Name: gtest
 7Description: gtest
 8Version: 1.8.0
 9Libs: -L${libdir} -lgtest -lpthread
10Cflags: -I${includedir}

Having done that, the following command:

1pkg-config  --libs --cflags gtest

should produce valid output, i.e. similar to

1-I/usr/local/include -L/usr/local/lib -lgtest -lpthread

Integrating googletest with cmake

If you use cmake to build your program, you can use pkg-config to find correct compilation flags.

First, in order to add support for pkg-config in cmake, add the following in CMakeLists.txt:

1find_package(PkgConfig)

Then, find gtest with pkg-config:

1pkg_check_modules(GTEST "gtest" REQUIRED)

You can verify that it’s available by printing GTEST_FOUND variable

1message(STATUS "gtest found: " ${GTEST_FOUND})

and running cmake . on your project.

After you confirm cmake can find the library, just add a definition for your test executable, e.g.

1add_executable(test_1
2  tests/test_1.cpp
3)

and then link gtest with it:

1target_link_libraries(test_1 ${GTEST_LIBRARIES})

Running build command e.g. cmake . && make should now successfully build the executable.

That concludes googletest installation. See the next section if you need to add googlemock (C++ mocking library).

Integrating googlemock with a C++ project

First, ensure you have copied libgmock*.a libraries to /usr/local/lib, i.e. by executing:

1sudo cp -r ./googlemock/libgmock*.a /usr/local/lib/

Create gmock.pc configuration file in /usr/lib/pkgconfig so that pkg-config can resolve compiler flags:

 1prefix=/usr/local
 2exec_prefix=${prefix}
 3libdir=${prefix}/lib
 4includedir=${prefix}/include
 5
 6Name: gmock
 7Description: gmock
 8Version: 1.8.0
 9Libs: -L${libdir} -lgmock -lpthread
10Cflags: -I${includedir}

Then, find gmock in CMakeLists.txt:

1pkg_check_modules(GMOCK "gmock" REQUIRED)

Finally, link your tests with googlemock by adding ${GMOCK_LIBRARIES} variable:

1target_link_libraries(test_readdir ${GTEST_LIBRARIES} ${GMOCK_LIBRARIES})

After all those steps, tests using googletest/googlemock should compile correctly by executing standard commands (cmake . && make)!