Add Plotly tests

.github/workflows/main.yml

@@ -34,11 +34,13 @@ jobs:
         run: cmake --install build/cmake/conda-debug-osmesa
       - name: Test
         run: python -m pytest ./test -k 'not plot'
-      - name: Graphical Test
+      - name: Plotly toolkit test
+        run: python -m pytest ./test -k 'plot_plotly'
+      - name: Notebook toolkit test
         if: matrix.os == 'ubuntu-latest'
         run: |
           sudo apt-get install libgl1-mesa-dev xvfb
-          xvfb-run python -m pytest ./test -k 'plot'
+          xvfb-run python -m pytest ./test -k 'plot_notebook'
 
   static-analysis:
     runs-on: "ubuntu-latest"

test/test_xoctave_kernel.py

@@ -55,3 +55,23 @@ def test_plot_notebook(self):
             content0["transient"]["display_id"],
             content1["transient"]["display_id"]
         )
+
+    def test_plot_plotly(self):
+        self.flush_channels()
+        reply, output_msgs = self.execute_helper(code="graphics_toolkit plotly; plot([])")
+
+        content0 = output_msgs[0]["content"]
+        self.assertEqual(output_msgs[0]["msg_type"], "display_data")
+
+        content1 = output_msgs[1]["content"]
+        self.assertEqual(output_msgs[1]["msg_type"], "update_display_data")
+        app1 = content1["data"]["application/vnd.plotly.v1+json"]
+        self.assertTrue(len(app1) > 0)
+        self.assertTrue(len(app1["layout"]) > 0)
+        self.assertTrue(app1["layout"]["height"] > 0)
+        self.assertTrue(app1["layout"]["width"] > 0)
+
+        self.assertEqual(
+            content0["transient"]["display_id"],
+            content1["transient"]["display_id"]
+        )