chore: add playwright tests (#783)

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### 🔗 Linked issue

<!-- If it resolves an open issue, please link the issue here. For
example "Resolves #123" -->

### 📚 Description

Add browser-based tests to verify that Storybook starts in development
mode. Aim is to catch errors like
#776

<!-- Describe your changes in detail -->
<!-- Why is this change required? What problem does it solve? -->

.github/workflows/ci.yml

@@ -49,6 +49,20 @@ jobs:
       - name: Build
         run: pnpm build
 
+      - name: Install Playwright Browsers
+        run: pnpm exec playwright install --with-deps
+
+      - name: Run Playwright tests
+        run: pnpm test:playwright
+
+      - name: Upload Playwright report
+        uses: actions/upload-artifact@v4
+        if: ${{ !cancelled() }}
+        with:
+          name: playwright-report-${{ runner.os }}-${{ matrix.node }}
+          path: playwright-report/
+          retention-days: 30
+
       - name: Nightly release
         if: |
           github.event_name == 'push' &&

.gitignore

@@ -21,3 +21,7 @@ storybook-static
 # Test artifacts
 coverage
 tsconfig.vitest-temp.json
+/test-results/
+/playwright-report/
+/blob-report/
+/playwright/.cache/

package.json

@@ -41,13 +41,16 @@
     "docs:generate": "pnpm run --filter=./docs/** generate",
     "test": "vitest run",
     "test:watch": "vitest watch",
-    "test:coverage": "vitest --coverage"
+    "test:coverage": "vitest --coverage",
+    "test:playwright": "pnpm exec playwright test"
   },
   "packageManager": "pnpm@9.10.0",
   "devDependencies": {
     "@nuxt/eslint-config": "0.5.7",
     "@nuxt/test-utils": "3.14.2",
     "@vitest/coverage-v8": "2.1.1",
+    "@playwright/test": "^1.47.2",
+    "@types/node": "^22.5.5",
     "changelogen": "0.5.5",
     "chromatic": "11.10.2",
     "eslint": "9.10.0",

playwright.config.ts

@@ -0,0 +1,80 @@
+import { defineConfig, devices } from '@playwright/test'
+
+/**
+ * Read environment variables from file.
+ * https://github.com/motdotla/dotenv
+ */
+// import dotenv from 'dotenv';
+// import path from 'path';
+// dotenv.config({ path: path.resolve(__dirname, '.env') });
+
+/**
+ * See https://playwright.dev/docs/test-configuration.
+ */
+export default defineConfig({
+  testDir: './test',
+  testMatch: '**/*.browser.ts',
+  /* Run tests in files in parallel */
+  fullyParallel: true,
+  /* Fail the build on CI if you accidentally left test.only in the source code. */
+  forbidOnly: !!process.env.CI,
+  /* Retry on CI only */
+  retries: process.env.CI ? 2 : 0,
+  /* Opt out of parallel tests on CI. */
+  workers: process.env.CI ? 1 : undefined,
+  /* Reporter to use. See https://playwright.dev/docs/test-reporters */
+  reporter: 'html',
+  /* Shared settings for all the projects below. See https://playwright.dev/docs/api/class-testoptions. */
+  use: {
+    /* Base URL to use in actions like `await page.goto('/')`. */
+    // baseURL: 'http://127.0.0.1:3000',
+
+    /* Collect trace when retrying the failed test. See https://playwright.dev/docs/trace-viewer */
+    trace: 'on-first-retry',
+  },
+
+  /* Configure projects for major browsers */
+  projects: [
+    {
+      name: 'chromium',
+      use: { ...devices['Desktop Chrome'] },
+    },
+
+    {
+      name: 'firefox',
+      use: { ...devices['Desktop Firefox'] },
+    },
+
+    {
+      name: 'webkit',
+      use: { ...devices['Desktop Safari'] },
+    },
+
+    /* Test against mobile viewports. */
+    // {
+    //   name: 'Mobile Chrome',
+    //   use: { ...devices['Pixel 5'] },
+    // },
+    // {
+    //   name: 'Mobile Safari',
+    //   use: { ...devices['iPhone 12'] },
+    // },
+
+    /* Test against branded browsers. */
+    // {
+    //   name: 'Microsoft Edge',
+    //   use: { ...devices['Desktop Edge'], channel: 'msedge' },
+    // },
+    // {
+    //   name: 'Google Chrome',
+    //   use: { ...devices['Desktop Chrome'], channel: 'chrome' },
+    // },
+  ],
+
+  /* Run your local dev server before starting the tests */
+  webServer: {
+    command: 'pnpm playground:storybook:dev',
+    url: 'http://127.0.0.1:6006',
+    reuseExistingServer: !process.env.CI,
+  },
+})

test/playground.storybook.browser.ts

@@ -0,0 +1,44 @@
+import { test, expect } from '@playwright/test'
+
+test('no errors', async ({ page }) => {
+  await page.goto('http://localhost:6006/iframe.html')
+  await page.locator('.sb-nopreview').waitFor() // That's the normal for the iframe with no story selected
+  await page.locator('.sb-preparing-story').waitFor({ state: 'hidden' })
+  await page.locator('.sb-preparing-docs').waitFor({ state: 'hidden' })
+
+  try {
+    await page
+      .locator('#error-message')
+      .waitFor({ state: 'visible', timeout: 1000 })
+  } catch {
+    // Ignore, error message is not visible and that's what we want
+  }
+
+  await expect(page.locator('#error-message')).toBeEmpty({ timeout: 1 })
+})
+
+test('renders the docs example', async ({ page }) => {
+  await page.goto(
+    'http://localhost:6006/iframe.html?viewMode=docs&id=example-nuxtwelcome--docs',
+  )
+  await page.locator('#storybook-docs').waitFor()
+  await page.locator('.sb-preparing-docs').waitFor({ state: 'hidden' })
+
+  const text = await page
+    .locator(
+      'div#story--example-nuxtwelcome--nuxt-welcome-story--primary-inner > h1',
+    )
+    .textContent()
+  expect(text).toContain('Welcome Nuxt to Storybook')
+})
+
+test('renders the story example', async ({ page }) => {
+  await page.goto(
+    'http://localhost:6006/iframe.html?viewMode=story&id=example-nuxtwelcome--nuxt-welcome-story',
+  )
+  await page.locator('#storybook-root').waitFor()
+  await page.locator('.sb-preparing-story').waitFor({ state: 'hidden' })
+
+  const text = await page.locator('#storybook-root > h1').textContent()
+  expect(text).toContain('Welcome Nuxt to Storybook')
+})

vitest.config.ts

@@ -7,5 +7,6 @@ export default defineVitestConfig({
       // Don't fail the test if typecheck of source files fails for the moment
       ignoreSourceErrors: true,
     },
+    include: ['test/*.spec.ts'],
   },
 })