Testing: Expand test_restart_interactive_backend with more cases

- Now we check if we request a restart by switch between different
backends several times.
- We also check that the Matplotlib status widget displays the right
value.

spyder/plugins/ipythonconsole/tests/conftest.py

@@ -207,6 +207,7 @@ def get_plugin(name):
     debugger.on_ipython_console_available()
     console.on_initialize()
     console._register()
+    console.get_widget().matplotlib_status.register_ipythonconsole(console)
     console.create_new_client(
         special=special,
         given_name=given_name,

spyder/plugins/ipythonconsole/tests/test_ipythonconsole.py

@@ -21,7 +21,6 @@
 
 # Third party imports
 from ipykernel._version import __version__ as ipykernel_version
-import IPython
 from IPython.core import release as ipy_release
 from IPython.core.application import get_ipython_dir
 from flaky import flaky
@@ -1909,18 +1908,61 @@ def test_pdb_comprehension_namespace(ipyconsole, qtbot, tmpdir):
         assert "_spyderpdb" not in key
 
 
-@flaky(max_runs=3)
+@flaky(max_runs=10)
 @pytest.mark.auto_backend
-def test_restart_intertactive_backend(ipyconsole, qtbot):
+def test_restart_interactive_backend(ipyconsole, qtbot):
     """
-    Test that we ask for a restart after switching to a different interactive
-    backend in preferences.
+    Test that we ask for a restart or not after switching to different
+    interactive backends.
+
+    Also, check that we show the right backend in the Matplotlib status widget.
     """
-    main_widget = ipyconsole.get_widget()
-    qtbot.wait(1000)
-    main_widget.change_possible_restart_and_mpl_conf('pylab/backend', 'tk')
+    shell = ipyconsole.get_current_shellwidget()
+    matplotlib_status = ipyconsole.get_widget().matplotlib_status
+
+    # This is necessary to test no spurious messages are printed to the console
+    shell.clear_console()
+    qtbot.waitUntil(lambda: '\nIn [2]: ' == shell._control.toPlainText())
+
+    # Switch to the tk backend
+    ipyconsole.set_conf('pylab/backend', 'tk')
+    assert bool(os.environ.get('BACKEND_REQUIRE_RESTART'))
+    assert shell.get_matplotlib_backend() == "qt"
+    assert matplotlib_status.value == "Qt"
+
+    # Switch to the inline backend
+    os.environ.pop('BACKEND_REQUIRE_RESTART')
+    ipyconsole.set_conf('pylab/backend', 'inline')
+    assert not bool(os.environ.get('BACKEND_REQUIRE_RESTART'))
+    qtbot.waitUntil(lambda: shell.get_matplotlib_backend() == "inline")
+    assert matplotlib_status.value == "Inline"
+
+    # Switch to the auto backend
+    ipyconsole.set_conf('pylab/backend', 'auto')
+    assert not bool(os.environ.get('BACKEND_REQUIRE_RESTART'))
+    qtbot.waitUntil(lambda: shell.get_matplotlib_backend() == "qt")
+    assert matplotlib_status.value == "Qt"
+
+    # Switch to the qt backend
+    ipyconsole.set_conf('pylab/backend', 'qt')
+    assert not bool(os.environ.get('BACKEND_REQUIRE_RESTART'))
+    assert matplotlib_status.value == "Qt"
+
+    # Switch to the tk backend again
+    ipyconsole.set_conf('pylab/backend', 'tk')
     assert bool(os.environ.get('BACKEND_REQUIRE_RESTART'))
 
+    # Check we no spurious messages are shown before the restart below
+    assert "\nIn [2]: " == shell._control.toPlainText()
+
+    # Restart kernel to check if the new interactive backend is set
+    ipyconsole.restart_kernel()
+    qtbot.waitUntil(lambda: shell.spyder_kernel_ready, timeout=SHELL_TIMEOUT)
+    qtbot.wait(SHELL_TIMEOUT)
+    qtbot.waitUntil(lambda: shell.get_matplotlib_backend() == "tk")
+    assert shell.get_mpl_interactive_backend() == "tk"
+    assert matplotlib_status.value == "Tk"
+
 
 def test_mpl_conf(ipyconsole, qtbot):
     """