Open Source Projects Using Google Mock and Google Test?

I had started my learning in automation testing,since I was a beginner ,I started to learn from open source projects like opencv,I wondered that they have not used any mocks like gmock and they used only google test. My questions,

Is it possible to do unit testing with only googletest if not,how many open source projects use only googletest?

Is there any open source projects which uses gmock testing?