Added unittest for back event

test/test_menu.py

@@ -151,7 +151,7 @@ def test_get_selected_widget(self):
         widget = self.menu.add_text_input('test', 'some_id')
         self.assertEqual(widget, self.menu.get_selected_widget())
 
-    def test_events(self):
+    def test_generic_events(self):
         """
         Test key events.
         """
@@ -209,6 +209,19 @@ def _some_event():
         click_pos = PygameUtils.get_middle_rect(first_button.get_rect())
         self.menu._main(PygameUtils.mouse_click(click_pos[0], click_pos[1]))
 
+    def test_back_event(self):
+        """
+        Test back event.
+        """
+        self.menu.clear()
+        self.assertEqual(self.menu._get_depth(), 0)
+        menu = PygameMenuUtils.generic_menu('submenu')
+        button = self.menu.add_option('open', menu)
+        button.apply()
+        self.assertEqual(self.menu._get_depth(), 1)
+        self.menu._main(PygameUtils.key(pygameMenu.controls.KEY_BACK, keydown=True))  # go back
+        self.assertEqual(self.menu._get_depth(), 0)
+
     def test_mouse_empty_submenu(self):
         """
         Test mouse event where the following submenu has less elements.