Raise missing ValueError in transform_angles

- Includes a small PEP8 change
- Added tests to cover the `Transform.transform_angles` method

lib/matplotlib/tests/test_transforms.py

@@ -9,6 +9,7 @@
 from nose.tools import assert_equal, assert_raises
 import numpy.testing as np_test
 from numpy.testing import assert_almost_equal, assert_array_equal
+from numpy.testing import assert_array_almost_equal
 from matplotlib.transforms import Affine2D, BlendedGenericTransform, Bbox
 from matplotlib.path import Path
 from matplotlib.scale import LogScale
@@ -535,6 +536,22 @@ def test_nan_overlap():
     assert not a.overlaps(b)
 
 
+def test_transform_angles():
+    t = mtrans.Affine2D()  # Identity transform
+    angles = np.array([20, 45, 60])
+    points = np.array([[0, 0], [1, 1], [2, 2]])
+
+    # Identity transform does not change angles
+    new_angles = t.transform_angles(angles, points)
+    assert_array_almost_equal(angles, new_angles)
+
+    # points missing a 2nd dimension
+    assert_raises(ValueError, t.transform_angles, angles, points[0:2, 0:1])
+
+    # Number of angles != Number of points
+    assert_raises(ValueError, t.transform_angles, angles, points[0:2, :])
+
+
 if __name__ == '__main__':
     import nose
     nose.runmodule(argv=['-s', '--with-doctest'],  exit=False)

lib/matplotlib/transforms.py

@@ -1468,9 +1468,10 @@ def transform_angles(self, angles, pts, radians=False, pushoff=1e-5):
         if pts.shape[1] != 2:
             raise ValueError("'pts' must be array with 2 columns for x,y")
 
-        if angles.ndim!=1 or angles.shape[0] != pts.shape[0]:
+        if angles.ndim != 1 or angles.shape[0] != pts.shape[0]:
             msg = "'angles' must be a column vector and have same number of"
             msg += " rows as 'pts'"
+            raise ValueError(msg)
 
         # Convert to radians if desired
         if not radians: