def test_neighbors_given_invalid():
"""
Test that invalid atoms raise error when calling neighbors.
"""
carb = AtomSpec(6, 4)
molecule = Molecule([carb], [])
with pytest.raises(ValueError):
molecule.neighbors(1)
def test_neighbors_expl():
"""
Test the number of neighbors, constructed with explicit H.
"""
carb = AtomSpec('C')
hyd = AtomSpec('H')
atoms = [carb, hyd, hyd, hyd, hyd]
bonds = [
BondSpec(0, 1, 1),
BondSpec(0, 2, 1),
BondSpec(0, 3, 1),
BondSpec(0, 4, 1),
]
molecule = Molecule(atoms, bonds)
assert len(molecule.neighbors(0)) == 4
def test_neighbors():
"""Test the number of neighbors."""
molecule = Molecule([AtomSpec('C', 4)], [])
assert not molecule.neighbors(0)