test(FN-4557): add type regression test for desktop node-pty shim

Fusion-Task-Id: FN-4557
Fusion-Task-Lineage: 53e20d45-b7e9-43d6-bf6f-2a5a3b568d4a

packages/desktop/src/__tests__/node-pty-types.test.ts

@@ -0,0 +1,43 @@
+import { describe, expect, expectTypeOf, it } from "vitest";
+import type { IEvent, IPty } from "node-pty";
+
+type SpawnFn = typeof import("node-pty")["spawn"];
+
+describe("node-pty ambient typing", () => {
+  it("keeps desktop node-pty shim aligned with expected IPty surface", () => {
+    const onDataEvent = ((listener: (data: string) => unknown) => {
+      listener("data");
+      return { dispose: () => undefined };
+    }) satisfies IEvent<string>;
+
+    const onExitEvent = ((listener: (e: { exitCode: number; signal?: number }) => unknown) => {
+      listener({ exitCode: 0, signal: 15 });
+      return { dispose: () => undefined };
+    }) satisfies IEvent<{ exitCode: number; signal?: number }>;
+
+    const pty: IPty = {
+      pid: 1,
+      cols: 80,
+      rows: 24,
+      process: "bash",
+      handleFlowControl: false,
+      onData: onDataEvent,
+      onExit: onExitEvent,
+      resize: (_cols: number, _rows: number) => undefined,
+      on: (_event: "data" | "exit", _listener: ((data: string) => void) | ((exitCode: number, signal?: number) => void)) => undefined,
+      clear: () => undefined,
+      write: (_data: string) => undefined,
+      kill: (_signal?: string) => undefined,
+      pause: () => undefined,
+      resume: () => undefined,
+    };
+
+    expectTypeOf(pty.kill).toEqualTypeOf<(signal?: string) => void>();
+    expectTypeOf(pty.onData).toEqualTypeOf<IEvent<string>>();
+    expectTypeOf(pty.onExit).toEqualTypeOf<IEvent<{ exitCode: number; signal?: number }>>();
+    expectTypeOf(pty.write).toEqualTypeOf<(data: string) => void>();
+    expectTypeOf(pty.resize).toEqualTypeOf<(cols: number, rows: number) => void>();
+    expectTypeOf<SpawnFn>().returns.toEqualTypeOf<IPty>();
+    expect(true).toBe(true);
+  });
+});