test(prompts): make Unicode symbol selection deterministic

Author: fengmk2

packages/prompts/src/__tests__/output.spec.ts

@@ -3,7 +3,7 @@ import { stripVTControlCharacters } from 'node:util';
 
 import stringWidth from 'fast-string-width';
 import color from 'picocolors';
-import { afterEach, describe, expect, it, vi } from 'vitest';
+import { afterEach, describe, expect, it, vi } from 'vite-plus/test';
 
 import { box } from '../box.js';
 import { settings, updateSettings } from '../index.js';
@@ -13,6 +13,9 @@ import { spinner } from '../spinner.js';
 import { stream } from '../stream.js';
 import { taskLog } from '../task-log.js';
 
+// common.ts selects symbols at module load, before test hooks run.
+vi.mock('is-unicode-supported', () => ({ default: () => true }));
+
 function capture(columns = 52, isTTY = false) {
   let content = '';
   const output = Object.assign(

packages/prompts/src/__tests__/render.spec.ts

@@ -1,4 +1,7 @@
-import { beforeEach, describe, expect, it, vi } from 'vitest';
+import { beforeEach, describe, expect, it, vi } from 'vite-plus/test';
+
+// Keep Unicode snapshots independent of the host terminal and platform.
+vi.mock('is-unicode-supported', () => ({ default: () => true }));
 
 type PromptConfig = {
   render: (this: Record<string, unknown>) => string;

packages/prompts/src/__tests__/unicode-fallback.spec.ts

@@ -0,0 +1,63 @@
+import { Writable } from 'node:stream';
+import { stripVTControlCharacters } from 'node:util';
+
+import { describe, expect, it, vi } from 'vite-plus/test';
+
+import { promptTitle } from '../common.js';
+import { log } from '../log.js';
+import { spinner } from '../spinner.js';
+
+// Select fallback symbols before common.ts and its consumers initialize.
+vi.mock('is-unicode-supported', () => ({ default: () => false }));
+
+function capture() {
+  let content = '';
+  const output = Object.assign(
+    new Writable({
+      write(chunk, _, done) {
+        content += chunk.toString();
+        done();
+      },
+    }),
+    { columns: 52, isTTY: false },
+  );
+  return { output, text: () => stripVTControlCharacters(content) };
+}
+
+describe('Unicode fallback output', () => {
+  it('preserves log severity and guide alignment with fallback symbols', () => {
+    const c = capture();
+    log.info('Checking assets\nChecking config', { output: c.output, withGuide: true });
+    log.success('Deployed', { output: c.output });
+    log.warn('Missing optional setting', { output: c.output });
+    log.error('Build failed', { output: c.output });
+
+    expect(c.text()).toBe(
+      '• Checking assets\n| Checking config\n* Deployed\n! Missing optional setting\nx Build failed\n',
+    );
+  });
+
+  it('uses fallback frames and completion symbols in a static spinner', () => {
+    const c = capture();
+    const s = spinner({ output: c.output });
+    s.start('Building');
+    s.stop('Built');
+
+    expect(c.text()).toBe('• Building...\no Built\n');
+  });
+
+  it.each([
+    ['active', '>'],
+    ['submit', 'o'],
+    ['cancel', 'x'],
+    ['error', 'x'],
+  ] as const)('renders a guided %s prompt title with fallback symbols', (state, marker) => {
+    const c = capture();
+    const title = promptTitle('Choose an option', state, {
+      output: c.output,
+      withGuide: true,
+    });
+
+    expect(stripVTControlCharacters(title)).toBe(`|\n${marker} Choose an option\n`);
+  });
+});