Some changes

Author: rhshadrach

pandas/plotting/_matplotlib/hist.py

@@ -303,7 +303,7 @@ def hist_series(
     yrot=None,
     figsize=None,
     bins=10,
-    legend=False,
+    legend: bool = False,
     **kwds,
 ):
     import matplotlib.pyplot as plt
@@ -376,7 +376,7 @@ def hist_frame(
     figsize=None,
     layout=None,
     bins=10,
-    legend=False,
+    legend: bool = False,
     **kwds,
 ):
     if by is not None:

pandas/tests/plotting/common.py

@@ -246,6 +246,7 @@ def _check_text_labels(self, texts, expected):
             assert texts.get_text() == expected
         else:
             labels = [t.get_text() for t in texts]
+            print(labels, expected)
             assert len(labels) == len(expected)
             for label, e in zip(labels, expected):
                 assert label == e

pandas/tests/plotting/test_groupby.py

@@ -8,7 +8,7 @@
 
 from pandas import DataFrame, Index, Series
 import pandas._testing as tm
-from pandas.tests.plotting.common import TestPlotBase
+from pandas.tests.plotting.common import TestPlotBase, _check_plot_works
 
 
 @td.skip_if_no_mpl
@@ -67,17 +67,40 @@ def test_plot_kwargs(self):
         res = df.groupby("z").plot.scatter(x="x", y="y")
         assert len(res["a"].collections) == 1
 
-
-@td.skip_if_no_mpl
-@pytest.mark.parametrize("column", [None, "b"])
-@pytest.mark.parametrize("label", [None, "d"])
-def test_hist_with_legend(column, label):
-    index = Index(15 * [1] + 15 * [2], name="c")
-    df = DataFrame(np.random.randn(30, 2), index=index, columns=["a", "b"])
-    g = df.groupby("c")
-
-    g.hist(column=column, label=label, legend=True)
-    tm.close()
-    if column != "b":
-        g["a"].hist(label=label, legend=True)
+    @pytest.mark.parametrize("column, expected_axes_num", [(None, 2), ("b", 1)])
+    @pytest.mark.parametrize("label", [None, "d"])
+    def test_groupby_hist_with_legend(self, column, expected_axes_num, label):
+        expected_layout = (1, expected_axes_num)
+        expected_labels = label or column or [["a"], ["b"]]
+
+        index = Index(15 * [1] + 15 * [2], name="c")
+        df = DataFrame(np.random.randn(30, 2), index=index, columns=["a", "b"])
+        g = df.groupby("c")
+
+        kwargs = {"legend": True, "column": column}
+        # Don't add "label": None, causes different behavior than no label kwarg
+        if label is not None:
+            kwargs["label"] = label
+
+        ret = g.hist(**kwargs)
+        for (_, axes) in ret.iteritems():
+            self._check_axes_shape(axes, axes_num=expected_axes_num, layout=expected_layout)
+            for ax, expected_label in zip(axes[0], expected_labels):
+                self._check_legend_labels(ax, expected_label)
         tm.close()
+
+    @pytest.mark.parametrize("label, expected_label", [(None, ['1', '2']), ("d", ["d", "d"])])
+    def test_groupby_hist_series_with_legend(self, label, expected_label):
+        index = Index(15 * [1] + 15 * [2], name="c")
+        df = DataFrame(np.random.randn(30, 2), index=index, columns=["a", "b"])
+        g = df.groupby("c")
+
+        kwargs = {"legend": True}
+        # Don't add "label": None, causes different behavior than no label kwarg
+        if label is not None:
+            kwargs["label"] = label
+
+        axes = g["a"].hist(**kwargs)
+        for (_, ax) in axes.iteritems():
+            self._check_axes_shape(ax, axes_num=1, layout=(1, 1))
+            self._check_legend_labels(ax, expected_label)

pandas/tests/plotting/test_hist_method.py

@@ -129,6 +129,23 @@ def test_plot_fails_when_ax_differs_from_figure(self):
         with pytest.raises(AssertionError):
             self.ts.hist(ax=ax1, figure=fig2)
 
+    @pytest.mark.slow
+    @pytest.mark.parametrize("by, expected_axes_num, expected_layout", [(None, 1, (1, 1)), ("b", 2, (1, 2))])
+    @pytest.mark.parametrize("label, expected_label", [(None, "a"), ("c", "c")])
+    def test_hist_with_legend(self, by, expected_axes_num, expected_layout, label, expected_label):
+        index = 15 * [1] + 15 * [2]
+        s = Series(np.random.randn(30), index=index, name="a")
+        s.index.name = "b"
+
+        kwargs = {"legend": True, "by": by}
+        if label is not None:
+            # Behavior differs if kwargs contains "label": None
+            kwargs["label"] = label
+
+        axes = _check_plot_works(s.hist, **kwargs)
+        self._check_axes_shape(axes, axes_num=expected_axes_num, layout=expected_layout)
+        self._check_legend_labels(axes, expected_label)
+
 
 @td.skip_if_no_mpl
 class TestDataFramePlots(TestPlotBase):
@@ -294,26 +311,30 @@ def test_hist_column_order_unchanged(self, column, expected):
         assert result == expected
 
     @pytest.mark.slow
-    @pytest.mark.parametrize("by", [None, "b"])
-    @pytest.mark.parametrize("label", [None, "c"])
-    def test_hist_with_legend(self, by, label):
-        expected_labels = label or "a"
-        expected_axes_num = 1 if by is None else 2
-        expected_layout = (1, 1) if by is None else (1, 2)
+    @pytest.mark.parametrize("by", [None, "c"])
+    @pytest.mark.parametrize("column", [None, "b"])
+    @pytest.mark.parametrize("label", [None, "d"])
+    def test_hist_with_legend(self, by, column, label):
+        expected_axes_num = 1 if by is None and column is not None else 2
+        expected_layout = (1, expected_axes_num)
+        expected_labels = label or column or ["a", "b"]
+        if by is not None:
+            expected_labels = [expected_labels] * 2
 
-        index = 15 * [1] + 15 * [2]
-        s = Series(np.random.randn(30), index=index, name="a")
-        s.index.name = "b"
+        index = Index(15 * [1] + 15 * [2], name="c")
+        df = DataFrame(np.random.randn(30, 2), index=index, columns=["a", "b"])
 
-        kwargs = {"legend": True, "by": by}
+        kwargs = {"legend": True, "by": by, "column": column}
         if label is not None:
             # Behavior differs if kwargs contains "label": None
             kwargs["label"] = label
 
-        _check_plot_works(s.hist, **kwargs)
-        axes = s.hist(**kwargs)
+        axes = _check_plot_works(df.hist, **kwargs)
         self._check_axes_shape(axes, axes_num=expected_axes_num, layout=expected_layout)
-        self._check_legend_labels(axes, expected_labels)
+        if by is None and column is None and label is None:
+            axes = axes[0]
+        for expected_label, ax in zip(expected_labels, axes):
+            self._check_legend_labels(ax, expected_label)
 
 
 @td.skip_if_no_mpl
@@ -506,30 +527,3 @@ def test_axis_share_xy(self):
 
         assert ax1._shared_y_axes.joined(ax1, ax2)
         assert ax2._shared_y_axes.joined(ax1, ax2)
-
-    @pytest.mark.slow
-    @pytest.mark.parametrize("by", [None, "c"])
-    @pytest.mark.parametrize("column", [None, "b"])
-    @pytest.mark.parametrize("label", [None, "d"])
-    def test_hist_with_legend(self, by, column, label):
-        expected_axes_num = 1 if by is None and column is not None else 2
-        expected_layout = (1, expected_axes_num)
-        expected_labels = label or column or ["a", "b"]
-        if by is not None:
-            expected_labels = [expected_labels] * 2
-
-        index = Index(15 * [1] + 15 * [2], name="c")
-        df = DataFrame(np.random.randn(30, 2), index=index, columns=["a", "b"])
-
-        kwargs = {"legend": True, "by": by, "column": column}
-        if label is not None:
-            # Behavior differs if kwargs contains "label": None
-            kwargs["label"] = label
-
-        _check_plot_works(df.hist, **kwargs)
-        axes = df.hist(**kwargs)
-        self._check_axes_shape(axes, axes_num=expected_axes_num, layout=expected_layout)
-        if by is None:
-            axes = axes[0]
-        for expected_label, ax in zip(expected_labels, axes):
-            self._check_legend_labels(ax, expected_label)