fix FutureWarning

comparison to `None` will result in an elementwise object comparison in the
future.

Author: nschloe

matplotlib2tikz/line2d.py

@@ -58,7 +58,7 @@ def draw_line2d(data, obj):
         mark_options = ['solid']
         if extra_mark_options:
             mark_options.append(extra_mark_options)
-        if marker_face_color in [None, 'none']:
+        if marker_face_color is None or marker_face_color == 'none':
             mark_options.append('fill opacity=0')
         else:
             data, face_xcolor, _ = mycol.mpl_color2xcolor(

test/helpers.py

@@ -144,7 +144,6 @@ def assert_phash(fig, reference_phash):
             print('Uploaded output PNG file to %s' % out.decode('utf-8'))
 
     assert reference_phash == phash
-
     return