def test_next_prerelease_invalid():
version = Version("1.1.1")
with pytest.raises(TypeError):
version.next_alpha("stuff")
with pytest.raises(TypeError):
version.next_beta("stuff")
with pytest.raises(TypeError):
version.next_release_candidate("stuff")
def test_next_beta(version_string, version_bump, expected):
version = Version(version_string)
next_version = version.next_beta(version_bump)
assert isinstance(next_version, Version)
assert next_version > version
assert str(next_version) == expected