def test_octahedral_molecule_should_have_eighteen_impropers():
bonds = [(0, 1), (0, 2), (0, 3), (0, 4), (0, 5), (0, 6)]
assert len(get_impropers(bonds)) == 60
def test_triangle_molecule_should_have_no_impropers():
bonds = [(0, 1), (0, 2), (1, 2)]
assert get_impropers(bonds) == []
def test_square_planar_molecule_should_have_twelve_impropers():
bonds = [(0, 1), (0, 2), (0, 3), (0, 4)]
assert get_impropers(bonds) == [(1, 0, 2, 3), (1, 0, 2, 4), (1, 0, 3, 4),
(2, 0, 1, 3), (2, 0, 1, 4), (2, 0, 3, 4),
(3, 0, 1, 2), (3, 0, 1, 4), (3, 0, 2, 4),
(4, 0, 1, 2), (4, 0, 1, 3), (4, 0, 2, 3)]
def test_tetrahedral_molecule_should_have_three_impropers():
bonds = [(0, 3), (1, 3), (2, 3)]
assert get_impropers(bonds) == [(0, 3, 1, 2), (1, 3, 0, 2), (2, 3, 0, 1)]
def test_square_molecule_should_have_no_impropers():
bonds = [(0, 1), (1, 2), (2, 3), (0, 3)]
assert get_impropers(bonds) == []
def test_different_order_of_bonds_should_return_same_impropers():
bonds = [(0, 1), (0, 2), (0, 3)]
assert get_impropers(bonds) == [(1, 0, 2, 3), (2, 0, 1, 3), (3, 0, 1, 2)]
bonds = [(0, 3), (0, 2), (0, 1)]
assert get_impropers(bonds) == [(1, 0, 2, 3), (2, 0, 1, 3), (3, 0, 1, 2)]
def test_four_atom_linear_molecule_should_have_no_impropers():
bonds = [(0, 1), (1, 2), (2, 3)]
assert get_impropers(bonds) == []