UI: Add workspace tool activation regression tests

Activates all tools in the 3D view, sequencer, node editor and image
editor. This can help finding regressions in tool activation, drawing
code or other related code.

Note that the sequencer test fails on Windows AMD64 Intel buildbot
workers. This same failure is already present in another test and seems
related to either a driver issue or the GPU module.

Pull Request: https://projects.blender.org/blender/blender/pulls/161585

tests/python/CMakeLists.txt

@@ -1784,6 +1784,10 @@ if(WITH_UI_TESTS)
     test_pie_menus.test_anim_keyframe_insert_pie_location
     test_pie_menus.test_weight_paint_vgroup_lock_pie
     test_button_input.test_string_buttons_interactions
+    test_tool_activation.view3d
+    test_tool_activation.image_editor
+    test_tool_activation.node_editor
+    test_tool_activation.sequencer
   )
   foreach(ui_test ${_ui_tests})
     add_blender_test_ui(

tests/python/ui_simulate/test_tool_activation.py

@@ -0,0 +1,221 @@
+# SPDX-FileCopyrightText: 2026 Blender Authors
+#
+# SPDX-License-Identifier: GPL-2.0-or-later
+
+"""
+This file does not run anything, its methods are accessed for tests by ``run_blender_setup.py``.
+"""
+
+import modules.ui_test_utils as ui
+
+
+def _setup_editor_area(area_type):
+    import bpy
+
+    bpy.ops.wm.read_homefile(use_empty=True)
+    e, t, window = ui.test_window()
+    area = ui.largest_area(window.screen)
+    area.type = area_type
+    yield
+
+    space = area.spaces.active
+    if hasattr(space, "show_region_toolbar"):
+        space.show_region_toolbar = True
+    yield
+
+    return e, t, window, area
+
+
+def _setup_view3d(tool_mode):
+    import bpy
+
+    e, t, window, area = yield from _setup_editor_area("VIEW_3D")
+    bpy.ops.mesh.primitive_cube_add()
+
+    if tool_mode == "OBJECT":
+        pass
+
+    elif tool_mode == "EDIT_MESH":
+        bpy.ops.object.mode_set(mode="EDIT")
+
+    elif tool_mode == "SCULPT":
+        bpy.ops.object.mode_set(mode="SCULPT")
+
+    else:
+        raise RuntimeError(f"Unsupported mode {tool_mode}")
+
+    return e, t, window, area
+
+
+def _setup_image_editor(mode):
+    import bpy
+
+    e, t, window, area = yield from _setup_editor_area("IMAGE_EDITOR")
+    space = area.spaces.active
+
+    bpy.ops.mesh.primitive_cube_add()
+    space.image = bpy.data.images.new("TestImage", width=256, height=256)
+    space.mode = mode
+
+    if mode == "PAINT":
+        bpy.ops.object.mode_set(mode="TEXTURE_PAINT")
+    elif mode == "UV":
+        bpy.ops.object.mode_set(mode="EDIT")
+    elif mode == "MASK":
+        space.mask = bpy.data.masks.new("TestMask")
+
+    return e, t, window, area
+
+
+def _setup_sequencer(view_type):
+    import bpy
+
+    e, t, window, area = yield from _setup_editor_area("SEQUENCE_EDITOR")
+
+    scene = bpy.context.scene
+    scene.sequence_editor_create()
+
+    scene.sequence_editor.strips.new_effect(
+        name="Color",
+        type='COLOR',
+        channel=1,
+        frame_start=1,
+        length=50,
+    )
+    yield
+
+    area.spaces.active.view_type = view_type
+    yield
+
+    return e, t, window, area
+
+
+def _get_tool_items(space_type, mode=None):
+    import bpy
+    from bl_ui.space_toolsystem_common import ToolSelectPanelHelper
+
+    tool_class = ToolSelectPanelHelper._tool_class_from_space_type(space_type)
+    if tool_class is None:
+        return []
+
+    items = ToolSelectPanelHelper._tools_flatten(
+        tool_class.tools_from_context(bpy.context, mode)
+    )
+
+    return [
+        item
+        for item in items
+        if item is not None and getattr(item, "idname", None)
+    ]
+
+
+def _get_active_tool_id(workspace, area):
+    import bpy
+
+    space = area.spaces.active
+
+    if area.type == "VIEW_3D":
+        return workspace.tools.from_space_view3d_mode(
+            bpy.context.mode,
+            create=True,
+        ).idname
+
+    if area.type == "IMAGE_EDITOR":
+        return workspace.tools.from_space_image_mode(
+            space.mode,
+            create=True,
+        ).idname
+
+    if area.type == "NODE_EDITOR":
+        return workspace.tools.from_space_node(create=True).idname
+
+    if area.type == "SEQUENCE_EDITOR":
+        return workspace.tools.from_space_sequencer(
+            space.view_type,
+            create=True,
+        ).idname
+
+    raise RuntimeError(f"Unsupported space type {area.type!r}")
+
+
+def _activate_tools_for_context(space_type, *, mode=None, setup_fn=None):
+    import bpy
+
+    if setup_fn is None:
+        def setup_fn(): return _setup_editor_area(space_type)
+
+    e, t, window, area = yield from setup_fn()
+
+    if space_type == "SEQUENCE_EDITOR":
+        if mode is None:
+            mode = area.spaces.active.view_type
+        region = next(r for r in area.regions if r.type == "WINDOW")
+    elif space_type == "IMAGE_EDITOR":
+        if mode is None:
+            mode = area.spaces.active.mode
+        region = next(r for r in area.regions if r.type == "WINDOW")
+    else:
+        region = None
+
+    center = ui.get_area_center(area)
+    for tool in _get_tool_items(space_type, mode):
+        yield e.cursor_position_set(*center, move=True)
+        yield
+
+        if region is None:
+            bpy.ops.wm.tool_set_by_id(
+                name=tool.idname,
+                space_type=space_type,
+            )
+        else:
+            # Some editors (e.g. the Image Editor and Sequencer) require an
+            # active window/area/region override for `wm.tool_set_by_id`.
+            with bpy.context.temp_override(
+                window=window,
+                area=area,
+                region=region,
+            ):
+                bpy.ops.wm.tool_set_by_id(
+                    name=tool.idname,
+                    space_type=space_type,
+                )
+
+        area.tag_redraw()
+        yield
+
+        active_tool_id = _get_active_tool_id(window.workspace, area)
+        t.assertEqual(active_tool_id, tool.idname)
+
+
+def view3d():
+    for mode in ("OBJECT", "EDIT_MESH", "SCULPT"):
+        yield from _activate_tools_for_context(
+            "VIEW_3D",
+            mode=mode,
+            setup_fn=lambda mode=mode: _setup_view3d(mode),
+        )
+
+
+def image_editor():
+    for mode in ("VIEW", "PAINT", "UV", "MASK"):
+        yield from _activate_tools_for_context(
+            "IMAGE_EDITOR",
+            mode=mode,
+            setup_fn=lambda mode=mode: _setup_image_editor(mode),
+        )
+
+
+def node_editor():
+    yield from _activate_tools_for_context("NODE_EDITOR")
+
+
+def sequencer():
+    for view_type in (
+        "SEQUENCER",
+        "PREVIEW",
+        "SEQUENCER_PREVIEW",
+    ):
+        yield from _activate_tools_for_context(
+            "SEQUENCE_EDITOR",
+            setup_fn=lambda view_type=view_type: _setup_sequencer(view_type),
+        )