Enhance image editing tests and functionality

- Added parameterized tests for image edit replacement to ensure alpha mode preservation.
- Refactored existing tests to utilize new image editing methods and improve clarity.
- Introduced new tests for image target functionality, ensuring proper handling of shared textures and context.
- Updated various tests to validate alpha mode handling across different scenarios.
- Improved undo/redo functionality in image operators to maintain state consistency.
- Added support for texture node actions, enhancing integration with Blender's node system.
- Ensured that image properties are preserved during operations and that invalid contexts are handled gracefully.

tests/anyimage/test_image_menu.py

@@ -96,12 +96,12 @@ class ImageMenuTest(BlenderTestCase):
 
     def test_image_operators_stay_clickable_until_server_is_busy(self):
         context = SimpleNamespace(
-            object=SimpleNamespace(data=SimpleNamespace()),
+            object=SimpleNamespace(type="EMPTY", empty_display_type="IMAGE", data=SimpleNamespace()),
         )
         operators = (
-            (self.convert_to_plane, self.convert_to_plane.ConvertToDepthPlane),
-            (self.convert_to_plane, self.convert_to_plane.ConvertToReliefPlane),
-            (self.remove_background, self.remove_background.RemoveImageBackground),
+            self.convert_to_plane.ConvertToDepthPlane,
+            self.convert_to_plane.ConvertToReliefPlane,
+            self.remove_background.RemoveImageBackground,
         )
 
         for busy, expected in ((False, True), (True, False)):
@@ -113,18 +113,6 @@ class ImageMenuTest(BlenderTestCase):
                     return_value=busy,
                 ),
             ):
-                for module, operator in operators:
-                    with (
-                        self.subTest(operator=operator.__name__),
-                        patch.object(
-                            module,
-                            "is_image_empty",
-                            return_value=True,
-                        ),
-                        patch.object(
-                            module,
-                            "video_total_frames",
-                            return_value=1,
-                        ),
-                    ):
+                for operator in operators:
+                    with self.subTest(operator=operator.__name__):
                         self.assertEqual(operator.poll(context), expected)