Merge branch 'main' into IS-1244

.github/workflows/cron-staging.yml

@@ -10,7 +10,7 @@ jobs:
     runs-on: ${{ matrix.os }}
     strategy:
       matrix:
-        python-version: [3.8, 3.9, "3.10", "3.11"]
+        python-version: [3.8, "3.11"]
         os: ["ubuntu-latest", "macOS-latest", "windows-latest"]
     steps:
       - name: Print Concurrency Group

test/visualization/test_plotter_mpldrawer.py

@@ -32,6 +32,11 @@
 class TestPlotterAndMplDrawer(QiskitExperimentsTestCase):
     """Test generic plotter with Matplotlib drawer."""
 
+    def tearDown(self):
+        """Clean up test case state"""
+        plt.close("all")
+        super().tearDown()
+
     def test_end_to_end_short(self):
         """Test whether plotter with MplDrawer returns a figure."""
         plotter = MockPlotter(MplDrawer())
@@ -118,7 +123,7 @@ def test_series_names_different_types(self, series_names: Dict[type, List[Any]])
         """
 
         # Create Matplotlib axes that use a PNG backend. The default backend, FigureCanvasSVG, does not
-        # have `tostring_rgb()` which is needed to compute the difference between two figures in this
+        # have `buffer_rgba()` which is needed to compute the difference between two figures in this
         # method. We need to set the axes as MplDrawer will use
         # `qiskit_experiments.framework.matplotlib.get_non_gui_ax` by default; which uses an SVG backend.
         plt.switch_backend("Agg")
@@ -161,16 +166,12 @@ def test_series_names_different_types(self, series_names: Dict[type, List[Any]])
                 for plot_type in legend_plot_types:
                     plotter.enable_legend_for(series_name, plot_type)
 
-        # Generate figure and save to buffers for comparison. This requires a pixel backend, like AGG, so
-        # that `tostring_rgb()` is available.
+        # Generate figure and save to buffers for comparison.
         figure_data = {}
         for plotter_type, plotter in plotters.items():
             figure = plotter.figure().figure
             figure.canvas.draw()
-            figure_data[plotter_type] = np.frombuffer(
-                figure.canvas.tostring_rgb(),
-                dtype=np.uint8,
-            ).reshape(figure.canvas.get_width_height() + (3,))
+            figure_data[plotter_type] = np.asarray(figure.canvas.buffer_rgba(), dtype=np.uint8)
 
         # Compare root-mean-squared error between two images.
         for (fig1_type, fig1), (fig2_type, fig2) in combinations(figure_data.items(), 2):