def test_etype_tuple_to_str():
    """Convert etype from tuple to string."""
    # Test for expected input.
    c_etype = ("user", "like", "item")
    c_etype_str = gb.etype_tuple_to_str(c_etype)
    assert c_etype_str == "user:like:item"

    # Test for unexpected input: not a tuple.
    c_etype = "user:like:item"
    with pytest.raises(
        AssertionError,
        match=re.escape(
            "Passed-in canonical etype should be in format of (str, str, str). "
            "But got user:like:item."
        ),
    ):
        _ = gb.etype_tuple_to_str(c_etype)

    # Test for unexpected input: tuple with wrong length.
    c_etype = ("user", "like")
    with pytest.raises(
        AssertionError,
        match=re.escape(
            "Passed-in canonical etype should be in format of (str, str, str). "
            "But got ('user', 'like')."
        ),
    ):
        _ = gb.etype_tuple_to_str(c_etype)
Convert etype from tuple to string.
tests/python/pytorch/graphbolt/test_base.py