def test_two_vectors(arrays):
array_a, array_b = arrays
vector_a = Vector(array_a)
is_perpendicular = vector_a.is_perpendicular(array_b)
is_parallel = vector_a.is_parallel(array_b)
# Two non-zero vectors cannot be both perpendicular and parallel.
assert not (is_perpendicular and is_parallel)
angle = vector_a.angle_between(array_b)
if is_perpendicular:
assert math.isclose(angle, np.pi / 2)
if is_parallel:
assert math.isclose(angle, 0, abs_tol=ATOL) or math.isclose(
angle, np.pi, rel_tol=1e-6)
# The zero vector is perpendicular and parallel to any other vector.
vector_zero = np.zeros(vector_a.size)
assert vector_a.is_perpendicular(vector_zero)
assert vector_a.is_parallel(vector_zero)
# The angle with the zero vector is undefined.
message_expected = "The vectors must have non-zero magnitudes."
with pytest.raises(ValueError, match=message_expected):
vector_a.angle_between(vector_zero)
# The projection of vector B onto A is parallel to A.
vector_b_projected = vector_a.project_vector(array_b)
assert vector_a.is_parallel(vector_b_projected)
# The projection is zero if vectors A and B are perpendicular.
if is_perpendicular:
assert vector_b_projected.is_zero(abs_tol=ATOL)
def test_is_parallel(array_u, array_v, bool_expected):
"""Test checking if vector u is parallel to vector v."""
vector_u = Vector(array_u)
assert vector_u.is_parallel(array_v) == bool_expected
