chore(cli): tests involving promptly don't work on GitHub Actions

packages/aws-cdk/lib/toolkit/cli-io-host.ts

@@ -183,6 +183,14 @@ export class CliIoHost implements IIoHost {
   private corkedCounter = 0;
   private readonly corkedLoggingBuffer: IoMessage<any>[] = [];
 
+  /**
+   * Stream to use for the input
+   *
+   * Should only be used for unit testing. Defaults to `process.stdin`
+   * which is what you usually want.
+   */
+  public testInputStream?: NodeJS.ReadableStream;
+
   private constructor(props: CliIoHostProps = {}) {
     this._currentAction = props.currentAction ?? 'none' as ToolkitAction;
     this._isTTY = props.isTTY ?? process.stdout.isTTY ?? false;
@@ -372,7 +380,9 @@ export class CliIoHost implements IIoHost {
       // Basic confirmation prompt
       // We treat all requests with a boolean response as confirmation prompts
       if (isConfirmationPrompt(msg)) {
-        const confirmed = await promptly.confirm(`${chalk.cyan(msg.message)} (y/n)`);
+        const confirmed = await promptly.confirm(`${chalk.cyan(msg.message)} (y/n)`, {
+          input: this.testInputStream,
+        });
         if (!confirmed) {
           throw new ToolkitError('Aborted by user');
         }
@@ -383,6 +393,7 @@ export class CliIoHost implements IIoHost {
       const prompt = extractPromptInfo(msg);
       const answer = await promptly.prompt(`${chalk.cyan(msg.message)} (${prompt.default})`, {
         default: prompt.default,
+        input: this.testInputStream,
       });
       return prompt.convertAnswer(answer);
     });

packages/aws-cdk/test/toolkit/cli-io-host.test.ts

@@ -1,6 +1,8 @@
+import { PassThrough } from 'stream';
 import * as chalk from 'chalk';
-import { CliIoHost, IoMessage, IoMessageLevel } from '../../lib/toolkit/cli-io-host';
-import { sendResponse } from '../_helpers/prompts';
+import { CliIoHost, IoMessage, IoMessageLevel, IoRequest } from '../../lib/toolkit/cli-io-host';
+
+let passThrough: PassThrough;
 
 const ioHost = CliIoHost.instance({
   logLevel: 'trace',
@@ -19,6 +21,7 @@ describe('CliIoHost', () => {
     ioHost.isTTY = process.stdout.isTTY ?? false;
     ioHost.isCI = false;
     ioHost.currentAction = 'synth';
+    ioHost.testInputStream = passThrough = new PassThrough();
 
     defaultMessage = {
       time: new Date('2024-01-01T12:00:00'),
@@ -243,8 +246,7 @@ describe('CliIoHost', () => {
 
     describe('boolean', () => {
       test('respond "yes" to a confirmation prompt', async () => {
-        sendResponse('y');
-        const response = await ioHost.requestResponse({
+        const response = await requestResponse('y', {
           time: new Date(),
           level: 'info',
           action: 'synth',
@@ -258,8 +260,7 @@ describe('CliIoHost', () => {
       });
 
       test('respond "no" to a confirmation prompt', async () => {
-        sendResponse('n');
-        await expect(() => ioHost.requestResponse({
+        await expect(() => requestResponse('n', {
           time: new Date(),
           level: 'info',
           action: 'synth',
@@ -279,8 +280,7 @@ describe('CliIoHost', () => {
         // simulate the enter key
         ['\x0A', 'cat'],
       ])('receives %p and returns %p', async (input, expectedResponse) => {
-        sendResponse(input);
-        const response = await ioHost.requestResponse({
+        const response = await requestResponse(input, {
           time: new Date(),
           level: 'info',
           action: 'synth',
@@ -300,8 +300,7 @@ describe('CliIoHost', () => {
         // simulate the enter key
         ['\x0A', 1],
       ])('receives %p and return %p', async (input, expectedResponse) => {
-        sendResponse(input);
-        const response = await ioHost.requestResponse({
+        const response = await requestResponse(input, {
           time: new Date(),
           level: 'info',
           action: 'synth',
@@ -378,3 +377,12 @@ describe('CliIoHost', () => {
     });
   });
 });
+
+/**
+ * Do a requestResponse cycle with the global ioHost, while sending input on the global fake input stream
+ */
+async function requestResponse<DataType, ResponseType>(input: string, msg: IoRequest<DataType, ResponseType>): Promise<ResponseType> {
+  const promise = ioHost.requestResponse(msg);
+  passThrough.write(input + '\n');
+  return promise;
+}