fix test_dates to chek for RuntimeError on identical date lim test

jdh2358 · jdh2358 · commit 252e016b7f62 · 2009-09-07T19:19:23.000Z
svn path=/trunk/matplotlib/; revision=7678
diff --git a/lib/matplotlib/axes.py b/lib/matplotlib/axes.py
@@ -2033,6 +2033,8 @@ def set_xlim(self, xmin=None, xmax=None, emit=True, **kwargs):
         if xmin is None: xmin = old_xmin
         if xmax is None: xmax = old_xmax
 
+        if xmin==xmax:
+            warnings.warn('Attempting to set identical xmin==xmax results in singular transformations; automatically expanding.  xmin=%s, xmax=%s'%(xmin, xmax))
         xmin, xmax = mtransforms.nonsingular(xmin, xmax, increasing=False)
         xmin, xmax = self.xaxis.limit_range_for_scale(xmin, xmax)
 
@@ -2205,6 +2207,9 @@ def set_ylim(self, ymin=None, ymax=None, emit=True, **kwargs):
         if ymin is None: ymin = old_ymin
         if ymax is None: ymax = old_ymax
 
+        if ymin==ymax:
+            warnings.warn('Attempting to set identical ymin==ymax results in singular transformations; automatically expanding.  ymin=%s, ymax=%s'%(ymin, ymax))
+
         ymin, ymax = mtransforms.nonsingular(ymin, ymax, increasing=False)
         ymin, ymax = self.yaxis.limit_range_for_scale(ymin, ymax)
         self.viewLim.intervaly = (ymin, ymax)
diff --git a/lib/matplotlib/tests/test_dates.py b/lib/matplotlib/tests/test_dates.py
@@ -2,6 +2,7 @@
 import numpy as np
 from matplotlib.testing.decorators import image_comparison, knownfailureif
 import matplotlib.pyplot as plt
+from nose.tools import assert_raises
 
 @image_comparison(baseline_images=['date_empty'])
 def test_date_empty():
@@ -66,13 +67,12 @@ def test_date_axvline():
     fig.autofmt_xdate()
     fig.savefig('date_axvline')
 
-# we want to test that this method raises a RuntimeError -- what is
-# the rightway to do this in the current framework
-@knownfailureif(True)
-#@image_comparison(baseline_images=['date_xlim_empty'])
-def test_set_xlim_and_unexpected_handling():
+def test_too_many_date_ticks():
     # Attempt to test SF 2715172, see
     # https://sourceforge.net/tracker/?func=detail&aid=2715172&group_id=80706&atid=560720
+    # setting equal datetimes triggers and expander call in
+    # transforms.nonsingular which results in too many ticks in the
+    # DayLocator.  This should trigger a Locator.MAXTICKS RuntimeError
     t0 = datetime.datetime(2000, 1, 20)
     tf = datetime.datetime(2000, 1, 20)
     fig = plt.figure()
@@ -81,13 +81,7 @@ def test_set_xlim_and_unexpected_handling():
     ax.plot([],[])
     from matplotlib.dates import DayLocator, DateFormatter, HourLocator
     ax.xaxis.set_major_locator(DayLocator())
-    ax.xaxis.set_major_formatter(DateFormatter("%m/%d/%y, %I:%M%p"))
-    ax.xaxis.set_minor_locator(HourLocator())
-    if 0:
-        # this seems to cause an ininite loop.
-        from nose.plugins.skip import SkipTest
-        raise SkipTest('avoiding never-ending drawing')
-    fig.savefig('date_xlim_empty')
+    assert_raises(RuntimeError, fig.savefig, 'junk.png')
 
 if __name__=='__main__':
     import nose
