tests: test_simple_workflow failing in CI

[ParthS007]

https://github.com/inveniosoftware/invenio-files-rest/pull/260/checks?check_run_id=1531895171#step:7:171

assert len(tmpdir.listdir()) == 2
E       AssertionError: assert 5 == 2
E          where 5 = len([local('/tmp/pytest-of-runner/pytest-0/test_simple_workflow0/e3'), local('/tmp/pytest-of-runner/pytest-0/test_simple_w...pytest-of-runner/pytest-0/test_simple_workflow0/48'), local('/tmp/pytest-of-runner/pytest-0/test_simple_workflow0/b1')])
E            where [local('/tmp/pytest-of-runner/pytest-0/test_simple_workflow0/e3'), local('/tmp/pytest-of-runner/pytest-0/test_simple_w...pytest-of-runner/pytest-0/test_simple_workflow0/48'), local('/tmp/pytest-of-runner/pytest-0/test_simple_workflow0/b1')] = <bound method LocalPath.listdir of local('/tmp/pytest-of-runner/pytest-0/test_simple_workflow0')>()
E              where <bound method LocalPath.listdir of local('/tmp/pytest-of-runner/pytest-0/test_simple_workflow0')> = local('/tmp/pytest-of-runner/pytest-0/test_simple_workflow0').listdir

tests/test_cli.py:106: AssertionError