ENH : raise on invalid linestyle

tacaswell · lennart0901 · commit a09d4adaece5 · 2015-04-14T08:33:41.000+02:00
Added check in code + test for raise
diff --git a/lib/matplotlib/lines.py b/lib/matplotlib/lines.py
@@ -977,7 +977,12 @@ def set_linestyle(self, linestyle):
                 break
 
         if linestyle not in self._lineStyles:
-            linestyle = ls_mapper_r.get(linestyle, linestyle)
+            try:
+                linestyle = ls_mapper_r[linestyle]
+            except KeyError:
+                raise ValueError("You passed in an invalid linestyle, see "
+                                 "docs of Line2D.set_linestyle for "
+                                 "valid values")
         if linestyle in [' ', '']:
             linestyle = 'None'
         self._linestyle = linestyle
diff --git a/lib/matplotlib/tests/test_lines.py b/lib/matplotlib/tests/test_lines.py
@@ -6,12 +6,13 @@
 
 import six
 
-from nose.tools import assert_true
+from nose.tools import assert_true, assert_raises
 from timeit import repeat
 import numpy as np
 import matplotlib as mpl
 import matplotlib.pyplot as plt
 from matplotlib.testing.decorators import cleanup, image_comparison
+import sys
 
 
 @cleanup
@@ -104,6 +105,17 @@ def test_linestyle_variants():
     assert True
 
 
+@cleanup
+def test_valid_linestyles():
+    if sys.version_info[:2] < (2, 7):
+        raise nose.SkipTest("assert_raises as context manager "
+                            "not supported with Python < 2.7")
+
+    line = mpl.lines.Line2D([], [])
+    with assert_raises(ValueError):
+        line.set_linestyle('aardvark')
+
+
 @image_comparison(baseline_images=['line_collection_dashes'], remove_text=True)
 def test_set_line_coll_dash_image():
     fig = plt.figure()
