Fix flaky unit test gui

When running some of the gui unit tests in parallell, they would share storage. This was very prevalent for the test unit_tests/gui/test_main_window.py::test_that_gui_plotter_works_when_no_data, where the PlotApi would return data from the other tests (which running esmda). This is fixed in this PR by mocking the return value from PlotApi.

tests/unit_tests/gui/test_main_window.py

@@ -40,6 +40,7 @@
     CaseSelectCheckButton,
     CaseSelectionWidget,
 )
+from ert.gui.tools.plot.plot_window import PlotApi
 from ert.gui.tools.plot.plot_window import PlotWindow
 from ert.run_models import SingleTestRun
 from ert.services import StorageService
@@ -765,31 +766,27 @@ def handle_error_dialog(run_dialog):
 
 
 @pytest.mark.usefixtures("use_tmpdir")
-def test_that_gui_plotter_works_when_no_data(qtbot, storage):
+def test_that_gui_plotter_works_when_no_data(qtbot, storage, monkeypatch):
+    monkeypatch.setattr(PlotApi, "_get_all_cases", lambda _: [])
     config_file = "minimal_config.ert"
     with open(config_file, "w", encoding="utf-8") as f:
         f.write("NUM_REALIZATIONS 1")
     args_mock = Mock()
     args_mock.config = config_file
-
     ert_config = ErtConfig.from_file(config_file)
     enkf_main = EnKFMain(ert_config)
-    with StorageService.init_service(
-        ert_config=config_file,
-        project=os.path.abspath(ert_config.ens_path),
-    ):
-        gui = _setup_main_window(enkf_main, args_mock, GUILogHandler())
-        gui.notifier.set_storage(storage)
-        qtbot.addWidget(gui)
-        gui.tools["Create plot"].trigger()
+    gui = _setup_main_window(enkf_main, args_mock, GUILogHandler())
+    gui.notifier.set_storage(storage)
+    qtbot.addWidget(gui)
+    gui.tools["Create plot"].trigger()
 
-        plot_window = wait_for_child(gui, qtbot, PlotWindow)
-        case_selection = get_child(plot_window, CaseSelectionWidget)
-        assert isinstance(case_selection, CaseSelectionWidget)
-        toggle_buttons = get_children(
-            case_selection, CaseSelectCheckButton, "case_selector"
-        )
-        assert len(toggle_buttons) == 0
+    plot_window = wait_for_child(gui, qtbot, PlotWindow)
+    case_selection = get_child(plot_window, CaseSelectionWidget)
+    assert isinstance(case_selection, CaseSelectionWidget)
+    toggle_buttons = get_children(
+        case_selection, CaseSelectCheckButton, "case_selector"
+    )
+    assert len(toggle_buttons) == 0
 
 
 @pytest.mark.usefixtures("copy_poly_case")