I searched for googletests using muon, but it looks like ubuntu doesn't have packages for it. Do I need to install using sources?
It is worth noting libgtest0 no longer exists. As of 2013 or so (I am not sure of the date of the change) see this question:
Old answer prior to 2012:
It is in the Ubuntu repositories
sudo apt-get install libgtest0 libgtest-dev
See also man gtest-config