Tag: googletest

Integrating googletest in CMake-based projects and Jenkins

In my – admittedly limited – perception unit testing in C++ projects does not seem as widespread as in Java or the dynamic languages like Ruby or Python. Therefore I would like to show how easy it can be to integrate unit testing in a CMake-based project and a continuous integration (CI) server. I will briefly cover why we picked googletest, adding unit testing to the build process and publishing the results.

Why we chose googletest

There are a plethora of unit testing frameworks for C++ making it difficult to choose the right one for your needs. Here are our reasons for googletest:

  • Easy publishing of result because of JUnit-compatible XML output. Many other frameworks need either a Jenkins-plugin or a XSLT-script to make that work.
  • Moderate compiler requirements and cross-platform support. This rules out xUnit++ and to a certain degree boost.test because they need quite modern compilers.
  • Easy to use and integrate. Since our projects use CMake as a build system googletest really shines here. CppUnit fails because of its verbose syntax and manual test registration.
  • No external dependencies. It is recommended to put googletest into your source tree and build it together with your project. This kind of self-containment is really what we love. With many of the other frameworks it is not as easy, CxxTest even requiring a Perl interpreter.

Integrating googletest into CMake project

  1. Putting googletest into your source tree
  2. Adding googletest to your toplevel CMakeLists.txt to build it as part of your project: 
    add_subdirectory(gtest-1.7.0)
  3. Adding the directory with your (future) tests to your toplevel CMakeLists.txt: 
    add_subdirectory(test)
  4. Creating a CMakeLists.txt for the test executables: 
    include_directories(${gtest_SOURCE_DIR}/include)
set(test_sources
# files containing the actual tests
)
add_executable(sample_tests ${test_sources})
target_link_libraries(sample_tests gtest_main)
  5. Implementing the actual tests like so (@see examples): 
    #include "gtest/gtest.h"

TEST(SampleTest, AssertionTrue) {
    ASSERT_EQ(1, 1);
}

Integrating test execution and result publishing in Jenkins

  1. Additional build step with shell execution containing something like: 
    cd build_dir && test/sample_tests --gtest_output="xml:testresults.xml"
  2. Activate “Publish JUnit test results” post-build action.

Conclusion

The setup of a unit testing environment for a C++ project is easier than many developers think. Using CMake, googletest and Jenkins makes it very similar to unit testing in Java projects.