standard-test-source: A new standard role to extract sources
    
    This logic is used when invoking tests that are packaged in the
    upstream tarball or sources. It is a technique used by the rpm-ostree
    and cockpit tests.
    
    Put this role in your tests.yml playbook. The playbook
    will extract the upstream source tarball as described in
    the package spec file into a test/source/ directory. You
    can then use or execute files (usually tests) from the
    upstream sources in your playbook.
    
    You can redefine the following variables:
    
     * srcdir: A directory to extract sources into. This defaults
       to {{ playbook_dir }}/source/
     * flatten: Strip one level of path prefix in source tree. This
       defaults to True