def test_given_parity():
"""Test a given parity."""
molecule = Molecule([AtomSpec('C', 4, parity=False)], [])
assert molecule.atom_parity(0) == Parity(False)
def test_atom_parity_given_invalid():
"""Test that invalid atoms raise error when calling parity."""
carb = AtomSpec(6, 4)
molecule = Molecule([carb], [])
with pytest.raises(ValueError):
molecule.atom_parity(1)
def test_parity():
"""Test the parity."""
molecule = Molecule([AtomSpec('C', 4)], [])
assert molecule.atom_parity(0) is None