OpenStudio C++ development is deep water, but step one is following these directions for setting up your build environment.

You need to make sure you configure with testing enabled.

Once you have a functioning build you can run all of the unit tests with ctest.

cd <openstudio-build-directory>/OSCore-prefix/src/OSCore-build/
ctest

OpenStudio unit tests are implemented using the gtest framework. GTest provides a main function that serves as the test runner. There are several different test runners (test executables) corresponding to different areas of the code. CTest on the other hand is like a meta test runner that wraps a single interface around the entire collection of tests. Using ctest the way I described above is the easiest way to run ALL of the tests, but you can also access the gtest runners directly with something like this for the Model API tests.

./<openstudio-build-directory>/OSCore-prefix/src/OSCore-build/Products/openstudio_model_tests

Here is an example of some of the Model tests.

The ctest and gtest interfaces both take a range of arguments to select specific tests and choose runner options. Use the --help option to see a list of their respective options.

 ctest --help
./<openstudio-build-directory>/OSCore-prefix/src/OSCore-build/Products/openstudio_model_tests --help