Merge branch 'master' into vector-like

.gitignore

@@ -1,3 +1,4 @@
 /.cache/
 /*.egg-info/
 __pycache__/
+.hypothesis/

.travis.yml

@@ -11,6 +11,11 @@ matrix:
     allow_failures:
         - python: "nightly"
 
+ cache:
+    directories:
+     - $HOME/.cache/pip
+     - .hypothesis
+
 before_install:
   - if [[ $MINICONDA_OS ]]; then
       URL="https://repo.continuum.io/miniconda/Miniconda3-latest-${MINICONDA_OS}-x86_64.sh";

dev-requirements.txt

@@ -1 +1,2 @@
 pytest~=3.8
+hypothesis

ppb_vector/vector2.py

@@ -137,6 +137,28 @@ def angle(self, other: VectorLike) -> Real:
         other = _mkvector(other, castto=Vector2)
         return degrees(acos(self.normalize() * other.normalize()))
 
+    def isclose(self, other: 'Vector2', *, rel_tol: float=1e-06, abs_tol: float=1e-3):
+        """
+        Determine whether two vectors are close in value.
+
+           rel_tol
+               maximum difference for being considered "close", relative to the
+               magnitude of the input values
+            abs_tol
+               maximum difference for being considered "close", regardless of the
+               magnitude of the input values
+        
+        Return True if self is close in value to other, and False otherwise.
+        
+        For the values to be considered close, the difference between them
+        must be smaller than at least one of the tolerances.
+        """
+        diff = (self - other).length
+        return (
+            diff < rel_tol * max(self.length, other.length) or 
+            diff < abs_tol
+        )
+
     def rotate(self, degrees: Real) -> 'Vector2':
         r = radians(degrees)
         r_cos = cos(r)

tests/utils.py

@@ -0,0 +1,18 @@
+from ppb_vector import Vector2
+import hypothesis.strategies as st
+
+vectors = lambda: st.builds(
+    Vector2,
+    st.floats(min_value=-1e300, max_value=1e300),
+    st.floats(min_value=-1e300, max_value=1e300)
+)
+
+@st.composite
+def units(draw, elements=st.floats(min_value=0, max_value=360)):
+    angle = draw(elements)
+    return Vector2(1, 0).rotate(angle)
+
+
+def angle_isclose(x, y, epsilon = 6.5e-5):
+    d = (x - y) % 360
+    return (d < epsilon) or (d > 360 - epsilon)