Fix bug: correct plotting on axes.

Closes #896

Author: drvinceknight

axelrod/plot.py

@@ -65,13 +65,14 @@ def _violinplot(
         spacing = 4
         positions = spacing * arange(1, self.nplayers + 1, 1)
         figure.set_size_inches(width, height)
-        plt.violinplot(data, positions=positions, widths=spacing / 2,
-                       showmedians=True, showextrema=False)
-        plt.xticks(positions, names, rotation=90)
-        plt.xlim(0, spacing * (self.nplayers + 1))
-        plt.tick_params(axis='both', which='both', labelsize=8)
+        ax.violinplot(data, positions=positions, widths=spacing / 2,
+                      showmedians=True, showextrema=False)
+        ax.set_xticks(positions)
+        ax.set_xticklabels(names, rotation=90)
+        ax.set_xlim([0, spacing * (self.nplayers + 1)])
+        ax.tick_params(axis='both', which='both', labelsize=8)
         if title:
-            plt.title(title)
+            ax.set_title(title)
         return figure
 
     # Box and Violin plots for mean score, score differences, wins, and match
@@ -260,11 +261,11 @@ def stackplot(
         ax.yaxis.set_label_position("right")
         ax.yaxis.labelpad = 25.0
 
-        plt.ylim([0.0, 1.0])
-        plt.ylabel('Relative population size')
-        plt.xlabel('Turn')
+        ax.set_ylim([0.0, 1.0])
+        ax.set_ylabel('Relative population size')
+        ax.set_xlabel('Turn')
         if title is not None:
-            plt.title(title)
+            ax.set_title(title)
 
         trans = transforms.blended_transform_factory(
             ax.transAxes, ax.transData)

axelrod/tests/unit/test_plot.py

@@ -137,6 +137,23 @@ def test_boxplot(self):
         else:  # pragma: no cover
             self.skipTest('matplotlib not installed')
 
+    def test_boxplot_with_passed_axes(self):
+        # Test that can plot on a given matplotlib axes
+        if matplotlib_installed:
+            fig, axarr = plt.subplots(2, 2)
+            self.assertEqual(axarr[0, 1].get_ylim(), (0, 1))
+            plot = axelrod.Plot(self.test_result_set)
+            plot.boxplot(ax=axarr[0, 1])
+            self.assertNotEqual(axarr[0, 1].get_ylim(), (0, 1))
+
+            # Plot on another axes with a title
+            plot.boxplot(title="Test", ax=axarr[1, 0])
+            self.assertNotEqual(axarr[1, 0].get_ylim(), (0, 1))
+            self.assertEqual(axarr[1, 0].get_title(), "Test")
+
+        else:  # pragma: no cover
+            self.skipTest('matplotlib not installed')
+
     def test_boxplot_with_title(self):
         if matplotlib_installed:
             plot = axelrod.Plot(self.test_result_set)
@@ -219,10 +236,11 @@ def test_payoff_with_title(self):
         else:  # pragma: no cover
             self.skipTest('matplotlib not installed')
 
-    def test_ecosystem(self):
+    def test_stackplot(self):
         if matplotlib_installed:
             eco = axelrod.Ecosystem(self.test_result_set)
             eco.reproduce(100)
+
             plot = axelrod.Plot(self.test_result_set)
             fig = plot.stackplot(eco)
             self.assertIsInstance(fig, matplotlib.pyplot.Figure)
@@ -236,6 +254,28 @@ def test_ecosystem(self):
         else:  # pragma: no cover
             self.skipTest('matplotlib not installed')
 
+    def test_stackplot_with_passed_axes(self):
+        # Test that can plot on a given matplotlib axes
+        if matplotlib_installed:
+            eco = axelrod.Ecosystem(self.test_result_set)
+            eco.reproduce(100)
+            plot = axelrod.Plot(self.test_result_set)
+
+            fig, axarr = plt.subplots(2, 2)
+            self.assertEqual(axarr[0, 1].get_xlim(), (0, 1))
+
+            plot.stackplot(eco, ax=axarr[0, 1])
+            self.assertNotEqual(axarr[0, 1].get_xlim(), (0, 1))
+
+            # Plot on another axes with a title
+            plot.stackplot(eco ,title="dummy title", ax=axarr[1, 0])
+            self.assertNotEqual(axarr[1, 0].get_xlim(), (0, 1))
+            self.assertEqual(axarr[1, 0].get_title(), "dummy title")
+
+        else:  # pragma: no cover
+            self.skipTest('matplotlib not installed')
+
+
     def test_all_plots(self):
         if matplotlib_installed:
             plot = axelrod.Plot(self.test_result_set)