Add test for interval on both axes

Author: mgunyho

xarray/tests/test_plot.py

@@ -832,6 +832,15 @@ def test_coord_with_interval_step_y(self):
         self.darray.groupby_bins("dim_0", bins).mean(...).plot.step(y="dim_0_bins")
         assert len(plt.gca().lines[0].get_xdata()) == ((len(bins) - 1) * 2)
 
+    def test_coord_with_interval_step_x_and_y_raises_valueeerror(self):
+        """Test that step plot with intervals both on x and y axes raises an error."""
+        arr = xr.DataArray(
+            [pd.Interval(0, 1), pd.Interval(1, 2)],
+            coords=[("x", [pd.Interval(0, 1), pd.Interval(1, 2)])],
+        )
+        with pytest.raises(TypeError, match="intervals against intervals"):
+            arr.plot.step()
+
 
 class TestPlotHistogram(PlotTestCase):
     @pytest.fixture(autouse=True)