Fix rounding bug in Vector2.rotation

ppb_vector/vector2.py

@@ -1,6 +1,6 @@
 import typing
 import collections
-from math import acos, cos, degrees, hypot, radians, sin
+from math import acos, cos, degrees, hypot, isclose, radians, sin
 from numbers import Real
 from collections.abc import Sequence
 
@@ -163,8 +163,10 @@ def rotate(self, degrees: Real) -> 'Vector2':
         r = radians(degrees)
         r_cos = cos(r)
         r_sin = sin(r)
-        x = round(self.x * r_cos - self.y * r_sin, 5)
-        y = round(self.x * r_sin + self.y * r_cos, 5)
+        assert isclose(r_cos * r_cos + r_sin * r_sin, 1)
+
+        x = self.x * r_cos - self.y * r_sin
+        y = self.x * r_sin + self.y * r_cos
         return Vector2(x, y)
 
     def normalize(self) -> 'Vector2':

tests/test_vector2_reflect.py

@@ -12,4 +12,4 @@
 
 @pytest.mark.parametrize("initial_vector, surface_normal, expected_vector", reflect_data)
 def test_reflect(initial_vector, surface_normal, expected_vector):
-    assert initial_vector.reflect(surface_normal) == expected_vector
+    assert initial_vector.reflect(surface_normal).isclose(expected_vector)

tests/test_vector2_rotate.py

@@ -1,4 +1,5 @@
 from ppb_vector import Vector2
+from utils import angle_isclose
 import pytest
 import math
 
@@ -17,8 +18,9 @@ def isclose(x, y, epsilon = 6.5e-5):
 
 @pytest.mark.parametrize('input, degrees, expected', data)
 def test_multiple_rotations(input, degrees, expected):
-    assert input.rotate(degrees) == expected
-    assert isclose(input.angle(expected), degrees)
+    assert input.rotate(degrees).isclose(expected)
+    assert angle_isclose(input.angle(expected), degrees)
+
 
 def test_for_exception():
     with pytest.raises(TypeError):