def test_bond():
b = Bond(0, 1)
assert b.get_bond_order() == 1
b1 = Bond(1, 0)
assert b == b1
assert b.get_nbr_atom_idx(1) == 0
def test_type_checking():
b = Bond(2, 0)
with pytest.raises(TypeError):
value_long = float(
2) # do not test long because it obsolete in python3
b.get_nbr_atom_idx(value_long)
