14:16:56 01:00         [chroot]
               Waiting for background workers to finish.
14:16:59 01:03   [complete]
               FAILURE

Exception message: Could not satisfy all requirements for six>=1.4:
    six>=1.4(from: unittest2), six==1.9.0(from: pantsbuild.pants.testinfra==0.0.51->pantsbuild.pants==0.0.51)