def test_slugify():
    assert slugify("a") == "a"
    assert slugify("1a") == "1a"
    assert slugify("1") == "1"
    assert slugify("a a") == "a_a"
    assert slugify(42) == "42"
    assert slugify(3.14159) == "314159"
    assert slugify("├── Node1") == "Node1"

    assert slugify("a", valid_variable_name=True) == "a"
    assert slugify("1a", valid_variable_name=True) == "Number_1a"
    assert slugify("1", valid_variable_name=True) == "Number_1"

    assert slugify("a", valid_variable_name=False) == "a"
    assert slugify("1a", valid_variable_name=False) == "1a"
    assert slugify("1", valid_variable_name=False) == "1"