def test_cross():
"""test the cross product of two 3 dimentional vectors"""
# Vector cross-product.
x = [1, 2, 3]
y = [4, 5, 6]
z = tnp.cross(x, y)
assert z == [-3, 6, -3]
def test_mdim_cross():
"""test the cross product of two 4 dimentional vectors"""
# Mixed dim cross-product.
x = [1, 2, 3]
y = [4, 5, 6, 7]
with pytest.raises(IndexError) as execinfo:
z = tnp.cross(x, y)
assert 'Vector has invalid dimensions' in str(execinfo.value)
