Fix test_open_console_when_no_kernel and move to test_main_widget.py

* The test that no console was opened did not work because this can be
  done asynchronously, so instead test for the signal requesting that
  the console be opened.
* The test now only needs the main widget, not the plugin, so move it
  accordingly.

Author: jitseniesen

spyder_notebook/tests/test_plugin.py

@@ -119,35 +119,6 @@ def fake_get_server(filename, interpreter, start):
 # =============================================================================
 # Tests
 # =============================================================================
-# Teardown sometimes fails on Mac with Python 3.8 due to NoProcessException
-# in shutdown_server() in notebookapp.py in external notebook library
-@flaky
-def test_open_console_when_no_kernel(notebook, qtbot, mocker):
-    """Test that open_console() handles the case when there is no kernel."""
-    # Create mock IPython console plugin and QMessageBox
-    MockMessageBox = mocker.patch(
-        'spyder_notebook.widgets.main_widget.QMessageBox')
-
-    # Wait for prompt
-    nbwidget = notebook.get_widget().tabwidget.currentWidget().notebookwidget
-    qtbot.waitUntil(lambda: prompt_present(nbwidget, qtbot),
-                    timeout=NOTEBOOK_UP)
-
-    # Shut the kernel down and check that this is successful
-    client = notebook.get_widget().tabwidget.currentWidget()
-    kernel_id = client.get_kernel_id()
-    sessions_url = client.get_session_url()
-    client.shutdown_kernel()
-    assert not is_kernel_up(kernel_id, sessions_url)
-
-    # Try opening a console
-    notebook.get_widget().open_console(client)
-
-    # Assert that a dialog is displayed and no console was opened
-    MockMessageBox.critical.assert_called()
-    ipyconsole = notebook.get_plugin(Plugins.IPythonConsole)
-    ipyconsole._create_client_for_kernel.assert_not_called()
-
 
 def test_on_mainwindow_visible_with_opened_notebooks(plugin_no_server):
     """

spyder_notebook/widgets/tests/test_main_widget.py

@@ -205,6 +205,34 @@ def test_shutdown_notebook_kernel(main_widget, qtbot):
     assert not is_kernel_up(kernel_id, sessions_url)
 
 
+@flaky
+def test_open_console_when_no_kernel(main_widget, qtbot, mocker):
+    """Test that open_console() handles the case when there is no kernel."""
+    # Create mock QMessageBox
+    MockMessageBox = mocker.patch(
+        'spyder_notebook.widgets.main_widget.QMessageBox')
+
+    # Create new notebook tab and wait for prompt
+    main_widget.create_new_client()
+    client = main_widget.tabwidget.currentWidget()
+    nbwidget = client.notebookwidget
+    qtbot.waitUntil(lambda: prompt_present(nbwidget, qtbot),
+                    timeout=NOTEBOOK_UP)
+
+    # Shut the kernel down and check that this is successful
+    kernel_id = client.get_kernel_id()
+    sessions_url = client.get_session_url()
+    client.shutdown_kernel()
+    assert not is_kernel_up(kernel_id, sessions_url)
+
+    # Try opening a console and check corresponding signal is not emitted
+    with qtbot.assertNotEmitted(main_widget.sig_open_console_requested):
+        main_widget.open_console(client)
+
+    # Assert that a dialog is displayed and no console was opened
+    MockMessageBox.critical.assert_called()
+
+
 def test_file_in_temp_dir_deleted_after_notebook_closed(main_widget, qtbot):
     """Test that notebook file in temporary directory is deleted after the
     notebook is closed."""