FIX: fix python2 unicode compatibility

Make sure we don't try to convert unicode strings to ascii

closes matplotlib#4765

Author: tacaswell

lib/matplotlib/axes/_axes.py

@@ -6079,7 +6079,7 @@ def hist(self, x, bins=10, range=None, normed=False, weights=None,
         elif is_string_like(label):
             labels = [label]
         else:
-            labels = [str(lab) for lab in label]
+            labels = [six.text_type(lab) for lab in label]
 
         for (patch, lbl) in zip_longest(patches, labels, fillvalue=None):
             if patch:

lib/matplotlib/tests/test_axes.py

@@ -3775,6 +3775,22 @@ def test_color_alias():
 def test_numerical_hist_label():
     fig, ax = plt.subplots()
     ax.hist([range(15)] * 5, label=range(5))
+    ax.legend()
+
+
+@cleanup
+def test_unicode_hist_label():
+    fig, ax = plt.subplots()
+    a = (b'\xe5\xbe\x88\xe6\xbc\x82\xe4\xba\xae, ' +
+         b'r\xc3\xb6m\xc3\xa4n ch\xc3\xa4r\xc3\xa1ct\xc3\xa8rs')
+    b = b'\xd7\xa9\xd7\x9c\xd7\x95\xd7\x9d'
+    labels = [a.decode('utf-8'),
+              'hi aardvark',
+              b.decode('utf-8'),
+              ]
+
+    ax.hist([range(15)] * 3, label=labels)
+    ax.legend()
 
 
 @cleanup
@@ -3785,6 +3801,7 @@ def test_move_offsetlabel():
     ax.yaxis.tick_right()
     assert_equal((1, 0.5), ax.yaxis.offsetText.get_position())
 
+
 @image_comparison(baseline_images=['rc_spines'], extensions=['png'],
                   savefig_kwarg={'dpi':40})
 def test_rc_spines():