refactor: enhance test framework with automated resource tracking and scripted error capture capabilities

addons/godot_ai/testing/test_suite.gd

@@ -31,6 +31,34 @@ func suite_teardown() -> void:
 	pass
 
 
+# ----- tracked allocations (freed by the runner after each test) -----
+
+var _tracked_objects: Array[Object] = []
+
+
+## Register a manually-managed Object (plain Object or out-of-tree Node) so
+## the runner frees it after the current test. RefCounted instances are
+## accepted but ignored because they manage their own lifetime.
+func track(obj: Object) -> Object:
+	if obj != null and not obj is RefCounted:
+		_tracked_objects.append(obj)
+	return obj
+
+
+## Free everything registered via track(). Called by the runner after each
+## test's teardown() and again after suite_teardown().
+func _free_tracked() -> void:
+	for obj in _tracked_objects:
+		if not is_instance_valid(obj) or (obj is Node and obj.is_queued_for_deletion()):
+			continue
+		if obj is Node:
+			var parent := (obj as Node).get_parent()
+			if parent != null:
+				parent.remove_child(obj)
+		obj.free()
+	_tracked_objects.clear()
+
+
 # ----- assertion state (managed by McpTestRunner) -----
 
 var _failed: bool = false
@@ -38,6 +66,7 @@ var _message: String = ""
 var _assertion_count: int = 0
 var _skipped: bool = false
 var _skip_reason: String = ""
+var _expected_script_error_substrings: Array[String] = []
 
 # ----- suite-level state (managed by McpTestRunner) -----
 
@@ -53,6 +82,7 @@ func _reset() -> void:
 	_assertion_count = 0
 	_skipped = false
 	_skip_reason = ""
+	_expected_script_error_substrings.clear()
 
 
 func _reset_suite_state() -> void:
@@ -121,6 +151,29 @@ func skip_on_godot_lt(min_version: String, reason: String = "") -> bool:
 	return false
 
 
+## Allow one captured SCRIPT ERROR whose text contains `substring`.
+## Use only for negative-path tests that intentionally compile or execute
+## invalid GDScript and assert on the resulting diagnostics.
+func expect_script_error_containing(substring: String) -> void:
+	_expected_script_error_substrings.append(substring)
+
+
+func _unexpected_script_errors(captured: PackedStringArray) -> PackedStringArray:
+	var unexpected := PackedStringArray()
+	var remaining := _expected_script_error_substrings.duplicate()
+	for error in captured:
+		var matched_index := -1
+		for i in range(remaining.size()):
+			if error.find(remaining[i]) != -1:
+				matched_index = i
+				break
+		if matched_index == -1:
+			unexpected.append(error)
+		else:
+			remaining.remove_at(matched_index)
+	return unexpected
+
+
 ## Trigger an undo against whichever history (scene or global) holds the most
 ## recent action. `EditorUndoRedoManager` in Godot 4.x doesn't expose `.undo()`
 ## directly — you resolve the history's underlying UndoRedo and call it there.