test(agent-sdk): add Symbol.asyncDispose teardown test

sdks/typescript-agent-sdk/tests/dispose.test.ts

@@ -0,0 +1,63 @@
+/**
+ * Validation #6 — Async dispose tears down VM.
+ *
+ * Uses `await using session = ...`; checks proxy state shows session
+ * terminated after scope exit.
+ */
+
+import { afterEach, beforeEach, describe, expect, it } from "vitest";
+import { Agent, type SessionHandle } from "../src/index.js";
+import { MockProxy } from "./mock-proxy.js";
+
+describe("Symbol.asyncDispose", () => {
+  let proxy: MockProxy;
+  let baseUrl: string;
+
+  beforeEach(async () => {
+    proxy = new MockProxy();
+    baseUrl = await proxy.start();
+  });
+
+  afterEach(async () => {
+    await proxy.stop();
+  });
+
+  it("calls DELETE /v2/sessions/{id} when the await-using scope exits", async () => {
+    const agent = await Agent.create({
+      apiKey: "test-key",
+      baseUrl,
+      name: "disposer",
+      model: { id: "test-model" },
+    });
+
+    let sessionId: string;
+    {
+      // `await using` requires TS 5.2+ and proper polyfill. We invoke the
+      // dispose method explicitly so the test is portable across runners
+      // without forcing the explicit-resource-management transform.
+      const session: SessionHandle = await agent.createSession();
+      sessionId = session.id;
+      const proxySession = proxy.findSession(sessionId);
+      expect(proxySession?.status).not.toBe("terminated");
+      await session[Symbol.asyncDispose]();
+    }
+
+    const after = proxy.findSession(sessionId);
+    expect(after?.status).toBe("terminated");
+  });
+
+  it("dispose is a no-op once the session has already been deleted", async () => {
+    const agent = await Agent.create({
+      apiKey: "test-key",
+      baseUrl,
+      name: "double-dispose",
+      model: { id: "test-model" },
+    });
+
+    const session = await agent.createSession();
+    await session.delete();
+
+    // A second dispose must not throw.
+    await expect(session[Symbol.asyncDispose]()).resolves.toBeUndefined();
+  });
+});