def test_is_vcs_installed(mocker, which_return, result) -> None:
    """Verify `is_vcs_installed` function correctly handles `which` answer."""
    mocker.patch('cookiecutter.vcs.which', autospec=True, return_value=which_return)
    assert vcs.is_vcs_installed('git') == result
Verify `is_vcs_installed` function correctly handles `which` answer.
tests/vcs/test_is_vcs_installed.py