TST: fix some mpl warnings (pandas-dev#38574)

Author: mzeitlin11

pandas/plotting/_matplotlib/misc.py

@@ -144,7 +144,9 @@ def normalize(series):
     df = frame.drop(class_column, axis=1).apply(normalize)
 
     if ax is None:
-        ax = plt.gca(xlim=[-1, 1], ylim=[-1, 1])
+        ax = plt.gca()
+        ax.set_xlim(-1, 1)
+        ax.set_ylim(-1, 1)
 
     to_plot: Dict[Label, List[List]] = {}
     colors = get_standard_colors(
@@ -260,7 +262,8 @@ def f(t):
     )
     colors = dict(zip(classes, color_values))
     if ax is None:
-        ax = plt.gca(xlim=(-np.pi, np.pi))
+        ax = plt.gca()
+        ax.set_xlim(-np.pi, np.pi)
     for i in range(n):
         row = df.iloc[i].values
         f = function(row)
@@ -440,7 +443,9 @@ def autocorrelation_plot(
     n = len(series)
     data = np.asarray(series)
     if ax is None:
-        ax = plt.gca(xlim=(1, n), ylim=(-1.0, 1.0))
+        ax = plt.gca()
+        ax.set_xlim(1, n)
+        ax.set_ylim(-1.0, 1.0)
     mean = np.mean(data)
     c0 = np.sum((data - mean) ** 2) / float(n)
 

pandas/tests/plotting/test_misc.py

@@ -71,10 +71,12 @@ def setup_method(self, method):
     def test_autocorrelation_plot(self):
         from pandas.plotting import autocorrelation_plot
 
-        _check_plot_works(autocorrelation_plot, series=self.ts)
-        _check_plot_works(autocorrelation_plot, series=self.ts.values)
+        # Ensure no UserWarning when making plot
+        with tm.assert_produces_warning(None):
+            _check_plot_works(autocorrelation_plot, series=self.ts)
+            _check_plot_works(autocorrelation_plot, series=self.ts.values)
 
-        ax = autocorrelation_plot(self.ts, label="Test")
+            ax = autocorrelation_plot(self.ts, label="Test")
         self._check_legend_labels(ax, labels=["Test"])
 
     def test_lag_plot(self):
@@ -132,8 +134,9 @@ def test_andrews_curves(self, iris):
         from pandas.plotting import andrews_curves
 
         df = iris
-
-        _check_plot_works(andrews_curves, frame=df, class_column="Name")
+        # Ensure no UserWarning when making plot
+        with tm.assert_produces_warning(None):
+            _check_plot_works(andrews_curves, frame=df, class_column="Name")
 
         rgba = ("#556270", "#4ECDC4", "#C7F464")
         ax = _check_plot_works(
@@ -280,7 +283,9 @@ def test_radviz(self, iris):
         from pandas.plotting import radviz
 
         df = iris
-        _check_plot_works(radviz, frame=df, class_column="Name")
+        # Ensure no UserWarning when making plot
+        with tm.assert_produces_warning(None):
+            _check_plot_works(radviz, frame=df, class_column="Name")
 
         rgba = ("#556270", "#4ECDC4", "#C7F464")
         ax = _check_plot_works(radviz, frame=df, class_column="Name", color=rgba)