Build failure: googletest *sources* are required

[htgoebel]

When having a pre-build package of googletest installed, build fails:

CMake Error at /usr/share/cmake-3.5/Modules/FindPackageHandleStandardArgs.cmake:148 (message):
  Could NOT find GTest (missing: GTEST_SOURCE_DIR)

googletest is installed, GTEST_INCLUDE_DIR is found. My pre-build package includes pre-build libraries (.a). Why do I need the sources?

[Lukáš Lalinský]

That's the recommended way to use gtest. It's a C++ library and the ABI depends on many compiler options. Debian based distributions don't even ship a compiled package of gtest anymore.

Given that gtest is only needed to run unit tests and not a run-time dependency, I think it's an acceptable trade-off to support just one way of using the library.