def test_can_get_nearby_atoms(self, mock_loc):
model = Mock()
mock_loc.return_value = (1, 2, 3)
atom = Atom("C", 4, 8, 3)
atom._model = model
model.atoms_in_sphere.return_value = [1, 2, atom, 4]
atoms = atom.nearby_atoms(4, a=1, b=2)
model.atoms_in_sphere.assert_called_with(1, 2, 3, 4, a=1, b=2)
self.assertEqual(atoms, [1, 2, 4])
def test_atom_with_no_model_has_no_nearby_atoms(self):
atom = Atom("C", 4, 8, 3)
self.assertEqual(atom.nearby_atoms(cutoff=1), set())
self.assertEqual(atom.nearby_atoms(cutoff=100), set())