move stdio (#13528)

packages/core/src/utils/stdio.test.ts

@@ -0,0 +1,68 @@
+/**
+ * @license
+ * Copyright 2025 Google LLC
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+import { describe, it, expect, vi, beforeEach, afterEach } from 'vitest';
+import { patchStdio, createInkStdio } from './stdio.js';
+import { coreEvents } from './events.js';
+
+vi.mock('./events.js', () => ({
+  coreEvents: {
+    emitOutput: vi.fn(),
+  },
+}));
+
+describe('stdio utils', () => {
+  let originalStdoutWrite: typeof process.stdout.write;
+  let originalStderrWrite: typeof process.stderr.write;
+
+  beforeEach(() => {
+    originalStdoutWrite = process.stdout.write;
+    originalStderrWrite = process.stderr.write;
+  });
+
+  afterEach(() => {
+    process.stdout.write = originalStdoutWrite;
+    process.stderr.write = originalStderrWrite;
+    vi.restoreAllMocks();
+  });
+
+  it('patchStdio redirects stdout and stderr to coreEvents', () => {
+    const cleanup = patchStdio();
+
+    process.stdout.write('test stdout');
+    expect(coreEvents.emitOutput).toHaveBeenCalledWith(
+      false,
+      'test stdout',
+      undefined,
+    );
+
+    process.stderr.write('test stderr');
+    expect(coreEvents.emitOutput).toHaveBeenCalledWith(
+      true,
+      'test stderr',
+      undefined,
+    );
+
+    cleanup();
+
+    // Verify cleanup
+    expect(process.stdout.write).toBe(originalStdoutWrite);
+    expect(process.stderr.write).toBe(originalStderrWrite);
+  });
+
+  it('createInkStdio writes to real stdout/stderr bypassing patch', () => {
+    const cleanup = patchStdio();
+    const { stdout: inkStdout, stderr: inkStderr } = createInkStdio();
+
+    inkStdout.write('ink stdout');
+    expect(coreEvents.emitOutput).not.toHaveBeenCalled();
+
+    inkStderr.write('ink stderr');
+    expect(coreEvents.emitOutput).not.toHaveBeenCalled();
+
+    cleanup();
+  });
+});