def test_subtraction_of_two_vectors_results_in_a_vector(self):
v1 = Vector(3, 2, 1)
v2 = Vector(5, 6, 7)
rv = v1.sub(v2)
assert rv.to_tuple() == (-2, -4, -6, 0)
def test_tuple_as_point_addition_results_in_new_tuple(self):
start = (3, -2, 5, 1) # emulates a Point
vector = Vector(-2, 3, 1)
dest = vector.add(start)
assert isinstance(dest, tuple)
assert dest is not start
def test_invalid_tuple_addition_raises_value_error(self):
vector = Vector(-2, 3, 1)
with pytest.raises(ValueError):
vector.add((1, 2, 3, 4)) # tuple that is not a Point or a Vector
def test_addition_to_tuple_as_vector(self):
v1 = Vector(2, 3, 1)
v2 = (3, 2, 1, 0)
vr = v1.add(v2)
# a vector added to a vector results in a resulting vector (w=0)
assert vr == (5, 5, 2, 0)
def test_point_addition_results_in_new_point_object(self):
starting_point = Point(3, -2, 5)
vector = Vector(-2, 3, 1)
destination = vector.add(starting_point)
assert isinstance(destination, Point)
assert destination is not starting_point
def test_creates_a_vector(self):
vector = Vector(1, 1, 1)
assert vector.w == 0.0
def test_addition_to_point_object(self):
point = Point(3, -2, 5)
vector = Vector(-2, 3, 1)
destination = vector.add(point)
# a point added to a vector results in a translated point (w=1)
assert destination.to_tuple() == (1, 1, 6, 1)
def test_unit_X_vector_has_a_magnitude_of_1(self):
assert Vector(1, 0, 0).magnitude() == 1
def test_unit_Z_vector_has_a_magnitude_of_1(self):
assert Vector(0, 0, 1).magnitude() == 1
def test_vector_scaling(self):
v1 = Vector(1, -2, 3)
assert v1.scale(3.5).to_tuple() == (3.5, -7, 10.5, 0)
assert v1.scale(0.5).to_tuple() == (0.5, -1, 1.5, 0)
assert v1.scale(-2).to_tuple() == (-2, 4, -6, 0)
def test_vector_scale_by_alias_is_implemented(self):
v1 = Vector(1, -2, 3)
assert v1.scale_by(3.5).to_tuple() == (3.5, -7, 10.5, 0)
def test_the_opposite_of_a_vector_is_its_negative(self):
v1 = Vector(3, 2, 1)
assert v1.opposite().to_tuple() == (-3, -2, -1, 0)
def test_recognizes_a_vector_in_a_tuple(self):
tup = (1.0, 1.0, 1.0, 0.0)
assert Vector.tuple_is_vector(tup)
def test_subtraction_of_a_point_from_a_vector_raises_type_error(self):
v1 = Vector(3, 2, 1)
pt = Point(5, 6, 7)
with pytest.raises(TypeError):
# subtract a point from a vector makes no sense
v1.sub(pt)
def test_incomplete_tuple_is_not_a_vector(self):
tup = (1, 1, 1)
assert not Vector.tuple_is_vector(tup)
def test_arbitrary_vector_has_a_magnitude(self):
assert Vector(1, 2, 3).magnitude() == math.sqrt(14)
assert Vector(-1, -2, -3).magnitude() == math.sqrt(14)
def test_builds_a_vector_from_a_tuple(self):
point = Vector.from_tuple((1, 1, 1))
assert Vector.object_is_vector(point)
def test_vector_magnitude_aliases_are_implemented(self):
assert Vector(1, 0, 0).length() == 1
assert Vector(1, 0, 0).len() == 1
assert Vector(1, 0, 0).mag() == 1
def test_vector_as_tuple(self):
vector = Vector(1, 1, 1)
assert vector.to_tuple() == (1.0, 1.0, 1.0, 0.0)
def test_arbitrary_vector_normalization(self):
assert Vector(1, 2, 3).normalize().mag() == 1
assert Vector(4, 0, 0).normalize().to_tuple() == (1, 0, 0, 0)
def test_addition_to_vector_object(self):
v1 = Vector(2, 3, 1)
v2 = Vector(3, 2, 1)
vr = v1.add(v2)
# a vector added to a vector results in a resulting vector (w=0)
assert vr.to_tuple() == (5, 5, 2, 0)
def test_vector_normalization_aliases_are_implemented(self):
assert Vector(4, 0, 0).normalized().to_tuple() == (1, 0, 0, 0)
assert Vector(4, 0, 0).norm().to_tuple() == (1, 0, 0, 0)
def test_vector_addition_results_in_new_vector_object(self):
v1 = Vector(2, 3, 1)
v2 = Vector(3, 2, 1)
vr = v1.add(v2)
assert isinstance(vr, Vector)
assert vr is not v1
def test_malformed_tuple_is_not_a_vector(self):
tup = (1, 1, 1, 1)
assert not Vector.tuple_is_vector(tup)
def test_recognizes_a_vector_in_a_vector_object(self):
vector = Vector(1.0, 1.0, 1.0)
assert Vector.object_is_vector(vector)
def test_vector_dot_product(self):
v1 = Vector(1, 2, 3)
v2 = Vector(2, 3, 4)
assert v1.dot(v2) == 20
def test_tuple_as_vector_addition_results_in_new_tuple(self):
v1 = (3, -2, 5, 0) # emulates a Vector
v2 = Vector(-2, 3, 1)
vr = v2.add(v1)
assert isinstance(vr, tuple)
assert vr is not v1
def test_point_tuple_is_not_a_vector(self):
tup = (1, 1, 1, 1)
assert not Vector.tuple_is_vector(tup)
def test_addition_invalid_type_argument_raises_type_error(self):
vector = Vector(-2, 3, 1)
with pytest.raises(TypeError):
# one can not add a scalar to a vector
vector.add(1)
def test_subtraction_of_a_vector_from_a_point_results_in_a_point(self):
p1 = Point(3, 2, 1)
v1 = Vector(5, 6, 7)
dp = p1.sub(v1)
assert dp.to_tuple() == (-2, -4, -6, 1)
