Without git installed check() fails with a bunch of errors like this:

  1) Error:
IndexRepositoryTest#test_read_tree_with_not_a_tree:
Errno::ENOENT: No such file or directory - git
    /home/user/aports/community/ruby-rugged/src/rugged-0.27.4/test/test_helper.rb:56:in ``'
    /home/user/aports/community/ruby-rugged/src/rugged-0.27.4/test/test_helper.rb:56:in `clone'
    /home/user/aports/community/ruby-rugged/src/rugged-0.27.4/test/index_test.rb:322:in `setup'