Merge pull request matplotlib#15460 from anntzer/axes_grid-check

Fix incorrect value check in axes_grid.

Author: jklymak

lib/mpl_toolkits/axes_grid1/axes_grid.py

@@ -499,7 +499,7 @@ def __init__(self, fig,
         if ngrids is None:
             ngrids = self._nrows * self._ncols
         else:
-            if not 0 <= ngrids < self._nrows * self._ncols:
+            if not 0 < ngrids <= self._nrows * self._ncols:
                 raise Exception
 
         self.ngrids = ngrids

lib/mpl_toolkits/tests/test_axes_grid1.py

@@ -102,6 +102,7 @@ def test_axesgrid_colorbar_log_smoketest(legacy_colorbar):
     fig = plt.figure()
     grid = AxesGrid(fig, 111,  # modified to be only subplot
                     nrows_ncols=(1, 1),
+                    ngrids=1,
                     label_mode="L",
                     cbar_location="top",
                     cbar_mode="single",