def get_installed_pypackages():
    return {p.project_name.lower(): p for p in pkg_resources.working_set}
def test_ccode_user_functions():
    x = symbols('x', integer=False)
    n = symbols('n', integer=True)
    custom_functions = {
        "ceiling": "ceil",
        "Abs": [(lambda x: not x.is_integer, "fabs"), (lambda x: x.is_integer, "abs")],
    }
    assert ccode(ceiling(x), user_functions=custom_functions) == "ceil(x)"
    assert ccode(Abs(x), user_functions=custom_functions) == "fabs(x)"
    assert ccode(Abs(n), user_functions=custom_functions) == "abs(n)"