test_dependency_resolution (layerindexlib.tests.cooker.LayerIndexCookerTest) ... ERROR

Stdout:
Loading plugins from ./lib/layerindexlib...
Loading plugin restapi
Loading plugin cooker
Loading plugin plugin
Loading: cooker://
Trying <class 'restapi.RestApiPlugin'>
restapi doesn't support cooker://
Trying <class 'cooker.CookerPlugin'>
Loading cooker data branches ['HEAD']

======================================================================
ERROR: test_dependency_resolution (layerindexlib.tests.cooker.LayerIndexCookerTest)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "./lib/bb/process.py", line 165, in run
    pipe = Popen(cmd, **options)
  File "./lib/bb/process.py", line 69, in __init__
    subprocess.Popen.__init__(self, *args, **options)
  File "/usr/lib/python3.8/subprocess.py", line 854, in __init__
    self._execute_child(args, executable, preexec_fn, close_fds,
  File "/usr/lib/python3.8/subprocess.py", line 1702, in _execute_child
    raise child_exception_type(errno_num, err_msg, err_filename)
FileNotFoundError: [Errno 2] No such file or directory: ''

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "./lib/layerindexlib/tests/cooker.py", line 36, in setUp
    self.layerindex.load_layerindex('cooker://', load=['layerDependencies'])
  File "./lib/layerindexlib/__init__.py", line 219, in load_layerindex
    indexEnt = plugin.load_index(indexURI, load)
  File "./lib/layerindexlib/cooker.py", line 178, in load_index
    index = self._load_bblayers(branches=branches)
  File "./lib/layerindexlib/cooker.py", line 100, in _load_bblayers
    (_, bb_branch, _, _) = self._get_bitbake_info()
  File "./lib/layerindexlib/cooker.py", line 59, in _get_bitbake_info
    bb_branch = self._run_command('git rev-parse --abbrev-ref HEAD', bb_path, default="<unknown>")
  File "./lib/layerindexlib/cooker.py", line 34, in _run_command
    result, _ = bb.process.run(command, cwd=path)
  File "./lib/bb/process.py", line 168, in run
    raise NotFoundError(cmd)
bb.process.NotFoundError: Execution of 'git rev-parse --abbrev-ref HEAD' failed: command not found

Stdout:
Loading plugins from ./lib/layerindexlib...
Loading plugin restapi
Loading plugin cooker
Loading plugin plugin
Loading: cooker://
Trying <class 'restapi.RestApiPlugin'>
restapi doesn't support cooker://
Trying <class 'cooker.CookerPlugin'>
Loading cooker data branches ['HEAD']

----------------------------------------------------------------------
Ran 425 tests in 103.699s

FAILED (errors=1, skipped=42)