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/support/blender.py

@@ -78,12 +78,17 @@ class BlenderTestCase(unittest.TestCase):
                 prepend=lambda draw: cls.outliner_menu_draws.insert(0, draw),
                 remove=lambda draw: cls.outliner_menu_draws.remove(draw),
             ),
+            NODE_MT_context_menu=SimpleNamespace(
+                prepend=lambda draw: cls.node_menu_draws.insert(0, draw),
+                remove=lambda draw: cls.node_menu_draws.remove(draw),
+            ),
         )
         cls.registered = []
         cls.registered_tools = []
         cls.status_bar_draws = []
         cls.context_menu_draws = []
         cls.outliner_menu_draws = []
+        cls.node_menu_draws = []
         fake_bpy.utils = SimpleNamespace(
             register_class=cls.registered.append,
             unregister_class=cls.registered.remove,
@@ -177,6 +182,7 @@ class BlenderTestCase(unittest.TestCase):
         self.status_bar_draws.clear()
         self.context_menu_draws.clear()
         self.outliner_menu_draws.clear()
+        self.node_menu_draws.clear()
         self.fake_bpy.data = SimpleNamespace(
             objects=SimpleNamespace(get=lambda _name: None),
         )

tests/support/image_texture.py

@@ -0,0 +1,45 @@
+from types import SimpleNamespace
+
+import bpy
+import numpy as np
+import pytest
+from PIL import Image
+
+
+@pytest.fixture
+def texture():
+    bpy.ops.wm.read_factory_settings(use_empty=True)
+    material = bpy.data.materials.new("Texture material")
+    material.use_nodes = True
+    material.use_fake_user = True
+    tree = material.node_tree
+    node = tree.nodes.new("ShaderNodeTexImage")
+    node.name = "Source texture"
+    node.image = bpy.data.images.new("Texture.png", width=4, height=3, alpha=True)
+    node.image.pixels.foreach_set(np.tile([0.2, 0.4, 0.6, 0.75], 12).astype(np.float32))
+    node.image.pack()
+    node.location = (-400, 100)
+    node.interpolation = "Closest"
+    node.extension = "CLIP"
+    node.projection = "BOX"
+    tree.nodes.active = node
+    tree.links.new(node.outputs["Color"], tree.nodes.get("Principled BSDF").inputs["Base Color"])
+    yield node
+    bpy.ops.wm.read_factory_settings(use_empty=True)
+
+
+def texture_context(node, **space_options):
+    return SimpleNamespace(
+        space_data=SimpleNamespace(
+            **dict(type="NODE_EDITOR", tree_type="ShaderNodeTree", shader_type="OBJECT",
+                   edit_tree=node.id_data, id=bpy.data.materials["Texture material"], **space_options),
+        ),
+        object=None,
+        scene=SimpleNamespace(anyimage_settings=SimpleNamespace(video_frames=16)),
+    )
+
+
+def write_result(directory, prefix="image.", count=1):
+    for index in range(1, count + 1):
+        Image.new("RGBA", (8, 6), (128, 64, 32, 80)).save(directory / f"{prefix}{index:04d}.png")
+