TST: plot methods return axes and test per #368, PR #385

Author: wesm

pandas/core/frame.py

@@ -3127,6 +3127,10 @@ def plot(self, subplots=False, sharex=True, sharey=False, use_index=True,
             pass
 
         plt.draw_if_interactive()
+        if subplots:
+            return axes
+        else:
+            return ax
 
     def _bar_plot(self, axes, subplots=False, use_index=True, grid=True,
                   rot=30, legend=True, **kwds):
@@ -3192,6 +3196,7 @@ def hist(self, grid=True, **kwds):
             ax.set_title(col)
             ax.grid(grid)
 
+        return axes
     #----------------------------------------------------------------------
     # Deprecated stuff
 

pandas/core/series.py

@@ -1684,6 +1684,8 @@ def plot(self, label=None, kind='line', use_index=True, rot=30, ax=None,
 
         plt.draw_if_interactive()
 
+        return ax
+
     def hist(self, ax=None, grid=True, **kwds):
         """
         Draw histogram of the input series using matplotlib
@@ -1710,6 +1712,8 @@ def hist(self, ax=None, grid=True, **kwds):
         ax.hist(values)
         ax.grid(grid)
 
+        return ax
+
     def to_csv(self, path):
         """
         Write the Series to a CSV file

pandas/tests/test_graphics.py

@@ -107,12 +107,14 @@ def _check_plot_works(f, *args, **kwargs):
     fig = plt.gcf()
     plt.clf()
     ax = fig.add_subplot(211)
-    f(*args, **kwargs)
+    ret = f(*args, **kwargs)
+    assert(ret is not None)  # do something more intelligent
 
     ax = fig.add_subplot(212)
     try:
         kwargs['ax'] = ax
-        f(*args, **kwargs)
+        ret = f(*args, **kwargs)
+        assert(ret is not None)  # do something more intelligent
     except Exception:
         pass
     plt.savefig(PNG_PATH)