test(backend): pin schema-linking structured response passthrough

backend/test/schema-linking-passthrough.test.ts

@@ -0,0 +1,35 @@
+import { test, expect, vi } from "vitest";
+import { SessionBridge } from "../src/bridge/session-bridge.js";
+
+function fakeRpc() {
+  const sent: any[] = [];
+  let evcb: any;
+  return {
+    rpc: {
+      send: (c: any) => sent.push(c),
+      on: (_: any, cb: any) => { evcb = cb; },
+      request: vi.fn(),
+    } as any,
+    sent,
+    fire: (m: any) => evcb(m),
+  };
+}
+
+test("respond forwards the structured schema-linking tables payload to Pi verbatim", () => {
+  const { rpc, sent, fire } = fakeRpc();
+  const b = new SessionBridge(rpc);
+  // Pi emits the ui request with its own RPC id ("pi-123"); the descriptor in the title
+  // carries the gate's own id ("u7"), matching the structured response below.
+  fire({ type: "extension_ui_request", id: "pi-123", method: "input", title: JSON.stringify({ id: "u7", widget: "schema-linking" }) });
+
+  const resp = { id: "u7", kind: "schema-linking", tables: [{ id: "t1", enacted: true, columns: ["cod_paz"] }] };
+  b.respond(resp);
+
+  // Correlates on Pi's own id, and JSON.stringifies the whole structured object untouched.
+  expect(sent.at(-1)).toEqual({
+    type: "extension_ui_response",
+    id: "pi-123",
+    value: JSON.stringify(resp),
+  });
+  expect(b.pendingWidget()).toBeNull();
+});