Activate selected overlay collection policies

internal/engine/source_version_test.go

@@ -1195,8 +1195,16 @@ func TestSourceVersionSelectedOverlayConsumesHeaderAndRetainsWarning(t *testing.
 	t.Parallel()
 
 	directory := t.TempDir()
-	mainPath := writeImportFile(t, directory, "main.yml", "schema: {version: main-v}\nsettings: {kept: base}\n")
-	overlayPath := writeImportFile(t, directory, "overlays/testing.yml", "schema: {version: overlay-v}\nsettings: {changed: overlay}\n")
+	mainPath := writeImportFile(t, directory, "main.yml", "schema: {version: main-v}\nsettings: {kept: base}\nitems: [{id: base}]\n")
+	overlayPath := writeImportFile(t, directory, "overlays/testing.yml", `schema: {version: overlay-v}
+configkit:
+  sequences:
+    - destination: [items]
+      key: id
+      mode: append
+settings: {changed: overlay}
+items: [{id: overlay}]
+`)
 	var checked []string
 	loaded, err := Load(File(mainPath), testSecretBinding(), Options[map[string]any]{
 		Overlay: "testing", SourceVersionMode: sourceVersionModeRequired,
@@ -1220,6 +1228,9 @@ func TestSourceVersionSelectedOverlayConsumesHeaderAndRetainsWarning(t *testing.
 	if loaded.Config["schema"].(map[string]any)["version"] != "main-v" || loaded.Config["settings"].(map[string]any)["changed"] != "overlay" {
 		t.Fatalf("overlay payload = %#v", loaded.Config)
 	}
+	if _, found := loaded.Config["configkit"]; found || len(loaded.Config["items"].([]any)) != 2 {
+		t.Fatalf("overlay declarations or collection values = %#v", loaded.Config)
+	}
 	diagnostics := loaded.Inspection.Diagnostics()
 	if len(diagnostics) != 1 || diagnostics[0].Code != CodeVersionWarning {
 		t.Fatalf("overlay warning was not retained: %#v", diagnostics)