TST: Verify functioning of histtype argument (GH23992)

Author: avinashpancham

pandas/tests/plotting/test_hist_method.py

@@ -129,6 +129,17 @@ def test_plot_fails_when_ax_differs_from_figure(self):
         with pytest.raises(AssertionError):
             self.ts.hist(ax=ax1, figure=fig2)
 
+    @pytest.mark.parametrize(
+        "histtype, expected",
+        [("bar", True), ("barstacked", True), ("step", False), ("stepfilled", True)],
+    )
+    def test_histtype_argument(self, histtype, expected):
+        # GH23992 Verify functioning of histtype argument
+        ser = Series(np.random.randint(1, 10))
+        ax = ser.hist(bins=12, alpha=0.5, histtype=histtype)
+        for patch in ax.patches:
+            assert patch.fill is expected
+
     @pytest.mark.parametrize(
         "by, expected_axes_num, expected_layout", [(None, 1, (1, 1)), ("b", 2, (1, 2))]
     )
@@ -365,6 +376,18 @@ def test_hist_column_order_unchanged(self, column, expected):
 
         assert result == expected
 
+    @pytest.mark.parametrize(
+        "histtype, expected",
+        [("bar", True), ("barstacked", True), ("step", False), ("stepfilled", True)],
+    )
+    def test_histtype_argument(self, histtype, expected):
+        # GH23992 Verify functioning of histtype argument
+        df = DataFrame(np.random.randint(1, 10, size=(100, 2)), columns=["a", "b"])
+        axes = df.hist(bins=12, alpha=0.5, histtype=histtype)
+        for ax in axes[0]:
+            for patch in ax.patches:
+                assert patch.fill is expected
+
     @pytest.mark.parametrize("by", [None, "c"])
     @pytest.mark.parametrize("column", [None, "b"])
     def test_hist_with_legend(self, by, column):
@@ -595,3 +618,18 @@ def test_axis_share_xy(self):
 
         assert ax1._shared_y_axes.joined(ax1, ax2)
         assert ax2._shared_y_axes.joined(ax1, ax2)
+
+    @pytest.mark.parametrize(
+        "histtype, expected",
+        [("bar", True), ("barstacked", True), ("step", False), ("stepfilled", True)],
+    )
+    def test_histtype_argument(self, histtype, expected):
+        # GH23992 Verify functioning of histtype argument
+        df = DataFrame(
+            np.random.randint(1, 10, size=(100, 2)), columns=["a", "b"]
+        ).groupby("a")
+        axes = df.hist(bins=12, alpha=0.5, histtype=histtype)
+        for sub_axes in axes:
+            for ax in sub_axes[0]:
+                for patch in ax.patches:
+                    assert patch.fill is expected