additional, self-explanatory tests

python/tests/test_Orientation.py

@@ -1,6 +1,8 @@
 import pytest
 import numpy as np
 from itertools import permutations
+from matplotlib import pyplot as plt
+from PIL import Image
 
 from damask import Rotation
 from damask import Orientation
@@ -520,3 +522,25 @@ class TestOrientation:
     def test_mul_invalid(self):
         with pytest.raises(TypeError):
             Orientation.from_random(lattice='cF')*np.ones(3)
+
+    @pytest.mark.parametrize('OR',['KS','NW','GT','GT_prime','Bain','Pitsch'])
+    @pytest.mark.parametrize('pole',[[0,0,1],[0,1,1],[1,1,1]])
+    def test_OR_plot(self,update,res_path,tmp_path,OR,pole):
+        # https://doi.org/10.3390/cryst13040663 for comparison
+        O = Orientation(lattice='cF')
+        poles = O.related(OR).to_pole(uvw=pole,with_symmetry=True).reshape(-1,3)
+        points = util.project_equal_area(poles,'z')
+
+        fig, ax = plt.subplots()
+        c = plt.Circle((0,0),1, color='k',fill=False)
+        ax.add_patch(c)
+        ax.scatter(points[:,0],points[:,1])
+        ax.set_aspect('equal', 'box')
+        fname=f'{OR}-{"".join(map(str,pole))}.png'
+        plt.axis('off')
+        plt.savefig(tmp_path/fname)
+        if update: plt.savefig(res_path/fname)
+        current = np.array(Image.open(tmp_path/fname))
+        reference = np.array(Image.open(res_path/fname))
+        assert np.allclose(current,reference)
+