def test_directory_not_exists():
    fs = FileSystem()
    assert not fs.exists('/fake/dir')
def test_directory_not_exists():
    fs = FileSystem()
    assert not fs.exists('/fake/dir')
def test_current_directory_exists():
    fs = FileSystem()
    assert fs.exists(ROOT_DIR)
def test_current_directory_exists():
    fs = FileSystem()
    assert fs.exists(ROOT_DIR)