TST: Adding test to test_style (pandas-dev#3188)

Author: bdrum

pandas/tests/plotting/test_style.py

@@ -1,3 +1,4 @@
+import matplotlib
 import pytest
 
 from pandas import Series
@@ -157,3 +158,11 @@ def test_empty_color_raises(self, color):
     def test_bad_color_raises(self, color):
         with pytest.raises(ValueError, match="Invalid color"):
             get_standard_colors(color=color, num_colors=5)
+
+
+class TestDefaultMplStyleParams:
+    def test_mplback_plot_by_default_use_axes_grid_from_rcparams(self):
+
+        # GH 3188
+        ax = Series([1, 2, 3, 4, 5]).plot()
+        assert matplotlib.rcParams["axes.grid"] == ax._gridOn