Unit testing is awesome. Working with legacy code, not so much. Of course when I say legacy code, I actually mean what Michael Feathers means: code that has no unit tests.

A while back I was getting started with googletest on Ubuntu and ran into this great post. Sadly, the libgtest-dev package does not install the static libraries, and the Ubuntu 14.04 repo is still stuck on the 1.6.0 verson. Can we do better (other than upgrading to 14.10)? Sure we can! Let’s grab the latest source from the googletest website and build our own! Of course, along the way we’re going to build and run the tests for googletest too. How meta. We’re going to need cmake.

$ sudo apt-get install cmake

Unzip the googletest source in your directory of choice. I’m a big fan of using /usr/local/src but it’s really a personal preference. Change to that directory and run the following cmake command to build the googletest static libraries in release mode and the googletest tests (case matters here for the cmake switches):

$ sudo cmake -DCMAKE_BUILD_TYPE=RELEASE -Dgtest_build_tests=ON
$ sudo make

Next we launch the tests like so:

$ make test

and you should see output that looks something like this:

Running tests...
Test project /usr/local/src/gtest-1.7.0
     Start  1: gtest-death-test_test
1/41 Test  #1: gtest-death-test_test ..............   Passed    0.84 sec
     Start  2: gtest_environment_test
2/41 Test  #2: gtest_environment_test .............   Passed    0.00 sec
     Start  3: gtest-filepath_test
3/41 Test  #3: gtest-filepath_test ................   Passed    0.01 sec
...

Make sure that all of the tests pass. Now it’s time to toss your compiled libraries somewhere that cmake will be able to find them:

$ sudo cp libgtest* /usr/lib

We’re going to need to add this line to our .zshrc (or similar shell) file so that cmake will be able to find the googletest headers.

export GTEST_ROOT="/usr/local/src/gtest-1.7.0"

How did I know this? Well if you look in the file /usr/share/cmake-2.8/Modules/FindGTest.cmake you will find the following section:

find_path(GTEST_INCLUDE_DIR gtest/gtest.h
    HINTS
        $ENV{GTEST_ROOT}/include
        ${GTEST_ROOT}/include
)

Because we’re building googletest from source in an unconventional directory, we’ll need to give cmake a hint as to where the googletest headers are.

If you didn’t want to add the environment variable, you could also have passed the location of the googletest headers as a switch to cmake:

$ cmake -DGTEST_ROOT="/usr/local/src/gtest-1.7.0/"

Now we’re all set. You can check everything is working by going back to this post and copy-pasta the source code and tests. Happy building!