25 KiB
Executable file
File Operations
When to use: Testing file uploads, downloads, drag-and-drop file interactions, file type validation, and download verification. Prerequisites: core/locators.md, core/assertions-and-waiting.md
Quick Reference
// Upload — single file
await page.getByLabel('Upload').setInputFiles('fixtures/resume.pdf');
// Upload — multiple files
await page.getByLabel('Upload').setInputFiles(['fixtures/a.png', 'fixtures/b.png']);
// Upload — clear selection
await page.getByLabel('Upload').setInputFiles([]);
// Download — wait and save
const download = await page.waitForEvent('download');
await page.getByRole('button', { name: 'Export CSV' }).click();
const path = await download.path(); // temp path
await download.saveAs('test-results/export.csv'); // permanent path
// File chooser dialog — non-input uploads
const fileChooser = await page.waitForEvent('filechooser');
await page.getByRole('button', { name: 'Choose file' }).click();
await fileChooser.setFiles('fixtures/photo.jpg');
Patterns
Single File Upload
Use when: A form has a standard <input type="file"> element.
Avoid when: The upload uses a drag-and-drop zone with no underlying file input.
TypeScript
import { test, expect } from '@playwright/test';
import path from 'path';
test('upload a single document', async ({ page }) => {
await page.goto('/settings/profile');
const filePath = path.join(__dirname, '../fixtures/avatar.png');
await page.getByLabel('Profile picture').setInputFiles(filePath);
// Verify the file name appears in the UI
await expect(page.getByText('avatar.png')).toBeVisible();
await page.getByRole('button', { name: 'Save' }).click();
await expect(page.getByText('Profile updated')).toBeVisible();
});
JavaScript
const { test, expect } = require('@playwright/test');
const path = require('path');
test('upload a single document', async ({ page }) => {
await page.goto('/settings/profile');
const filePath = path.join(__dirname, '../fixtures/avatar.png');
await page.getByLabel('Profile picture').setInputFiles(filePath);
await expect(page.getByText('avatar.png')).toBeVisible();
await page.getByRole('button', { name: 'Save' }).click();
await expect(page.getByText('Profile updated')).toBeVisible();
});
Multiple File Upload
Use when: The file input accepts multiple and you need to attach several files at once.
Avoid when: The UI only allows one file. Use single file upload.
TypeScript
import { test, expect } from '@playwright/test';
import path from 'path';
test('upload multiple attachments', async ({ page }) => {
await page.goto('/tickets/new');
const fixtures = ['doc1.pdf', 'doc2.pdf', 'screenshot.png'].map(
(f) => path.join(__dirname, '../fixtures', f)
);
await page.getByLabel('Attachments').setInputFiles(fixtures);
// Verify all files are listed
await expect(page.getByTestId('file-list').getByRole('listitem')).toHaveCount(3);
// Remove one file by clearing and re-setting
await page.getByLabel('Attachments').setInputFiles(fixtures.slice(0, 2));
await expect(page.getByTestId('file-list').getByRole('listitem')).toHaveCount(2);
});
JavaScript
const { test, expect } = require('@playwright/test');
const path = require('path');
test('upload multiple attachments', async ({ page }) => {
await page.goto('/tickets/new');
const fixtures = ['doc1.pdf', 'doc2.pdf', 'screenshot.png'].map(
(f) => path.join(__dirname, '../fixtures', f)
);
await page.getByLabel('Attachments').setInputFiles(fixtures);
await expect(page.getByTestId('file-list').getByRole('listitem')).toHaveCount(3);
await page.getByLabel('Attachments').setInputFiles(fixtures.slice(0, 2));
await expect(page.getByTestId('file-list').getByRole('listitem')).toHaveCount(2);
});
File Chooser Dialog
Use when: The upload is triggered by a button click that opens the native file picker, not by a visible <input type="file">. Common with drag-and-drop libraries and custom upload components.
Avoid when: There is a visible <input type="file"> — use setInputFiles directly.
TypeScript
import { test, expect } from '@playwright/test';
test('upload via file chooser dialog', async ({ page }) => {
await page.goto('/documents');
// Register the listener BEFORE the click that opens the dialog
const fileChooserPromise = page.waitForEvent('filechooser');
await page.getByRole('button', { name: 'Upload document' }).click();
const fileChooser = await fileChooserPromise;
// Verify dialog properties
expect(fileChooser.isMultiple()).toBe(false);
await fileChooser.setFiles('fixtures/report.pdf');
await expect(page.getByText('report.pdf')).toBeVisible();
});
test('upload multiple via file chooser', async ({ page }) => {
await page.goto('/gallery');
const fileChooserPromise = page.waitForEvent('filechooser');
await page.getByRole('button', { name: 'Add photos' }).click();
const fileChooser = await fileChooserPromise;
expect(fileChooser.isMultiple()).toBe(true);
await fileChooser.setFiles(['fixtures/photo1.jpg', 'fixtures/photo2.jpg']);
await expect(page.getByRole('img')).toHaveCount(2);
});
JavaScript
const { test, expect } = require('@playwright/test');
test('upload via file chooser dialog', async ({ page }) => {
await page.goto('/documents');
const fileChooserPromise = page.waitForEvent('filechooser');
await page.getByRole('button', { name: 'Upload document' }).click();
const fileChooser = await fileChooserPromise;
expect(fileChooser.isMultiple()).toBe(false);
await fileChooser.setFiles('fixtures/report.pdf');
await expect(page.getByText('report.pdf')).toBeVisible();
});
test('upload multiple via file chooser', async ({ page }) => {
await page.goto('/gallery');
const fileChooserPromise = page.waitForEvent('filechooser');
await page.getByRole('button', { name: 'Add photos' }).click();
const fileChooser = await fileChooserPromise;
expect(fileChooser.isMultiple()).toBe(true);
await fileChooser.setFiles(['fixtures/photo1.jpg', 'fixtures/photo2.jpg']);
await expect(page.getByRole('img')).toHaveCount(2);
});
Drag-and-Drop File Upload
Use when: The UI has a drop zone that accepts files via the HTML5 Drag and Drop API and has no <input type="file"> fallback.
Avoid when: A file input exists — even hidden ones work with setInputFiles.
TypeScript
import { test, expect } from '@playwright/test';
import fs from 'fs';
import path from 'path';
test('drop file onto upload zone', async ({ page }) => {
await page.goto('/upload');
// Read the file into a buffer
const filePath = path.join(__dirname, '../fixtures/data.csv');
const buffer = fs.readFileSync(filePath);
// Create a DataTransfer with the file and dispatch drop event
const dropZone = page.getByTestId('drop-zone');
await dropZone.dispatchEvent('drop', {
dataTransfer: {
files: [
{ name: 'data.csv', mimeType: 'text/csv', buffer },
],
},
});
await expect(page.getByText('data.csv')).toBeVisible();
await expect(page.getByText('Upload complete')).toBeVisible();
});
test('drag-and-drop with hidden input fallback', async ({ page }) => {
await page.goto('/upload');
// Many drag-and-drop libraries still use a hidden <input type="file">
// Check for it first — this is more reliable than simulating DnD events
const hiddenInput = page.locator('input[type="file"]');
if (await hiddenInput.count() > 0) {
await hiddenInput.setInputFiles('fixtures/data.csv');
}
await expect(page.getByText('data.csv')).toBeVisible();
});
JavaScript
const { test, expect } = require('@playwright/test');
const fs = require('fs');
const path = require('path');
test('drop file onto upload zone', async ({ page }) => {
await page.goto('/upload');
const filePath = path.join(__dirname, '../fixtures/data.csv');
const buffer = fs.readFileSync(filePath);
const dropZone = page.getByTestId('drop-zone');
await dropZone.dispatchEvent('drop', {
dataTransfer: {
files: [
{ name: 'data.csv', mimeType: 'text/csv', buffer },
],
},
});
await expect(page.getByText('data.csv')).toBeVisible();
await expect(page.getByText('Upload complete')).toBeVisible();
});
test('drag-and-drop with hidden input fallback', async ({ page }) => {
await page.goto('/upload');
const hiddenInput = page.locator('input[type="file"]');
if (await hiddenInput.count() > 0) {
await hiddenInput.setInputFiles('fixtures/data.csv');
}
await expect(page.getByText('data.csv')).toBeVisible();
});
File Download — Wait and Verify
Use when: Testing export buttons, report generation, or any action that triggers a browser download. Avoid when: The file is served as a page navigation (opens in a new tab). Use multi-tab patterns instead.
TypeScript
import { test, expect } from '@playwright/test';
import fs from 'fs';
test('download and verify file content', async ({ page }) => {
await page.goto('/reports');
// Register BEFORE the click that triggers the download
const downloadPromise = page.waitForEvent('download');
await page.getByRole('button', { name: 'Export CSV' }).click();
const download = await downloadPromise;
// Verify download metadata
expect(download.suggestedFilename()).toBe('report-2025.csv');
// Save to a known location
const savePath = 'test-results/report.csv';
await download.saveAs(savePath);
// Read and verify content
const content = fs.readFileSync(savePath, 'utf-8');
expect(content).toContain('Name,Email,Status');
expect(content).toContain('Jane Doe,jane@example.com,Active');
// Verify file size is reasonable
const stats = fs.statSync(savePath);
expect(stats.size).toBeGreaterThan(100);
});
test('download triggered by a link', async ({ page }) => {
await page.goto('/files');
const downloadPromise = page.waitForEvent('download');
await page.getByRole('link', { name: 'Download invoice' }).click();
const download = await downloadPromise;
expect(download.suggestedFilename()).toMatch(/invoice-\d+\.pdf/);
// Use download.path() for the temp file path
const tempPath = await download.path();
expect(tempPath).toBeTruthy();
});
JavaScript
const { test, expect } = require('@playwright/test');
const fs = require('fs');
test('download and verify file content', async ({ page }) => {
await page.goto('/reports');
const downloadPromise = page.waitForEvent('download');
await page.getByRole('button', { name: 'Export CSV' }).click();
const download = await downloadPromise;
expect(download.suggestedFilename()).toBe('report-2025.csv');
const savePath = 'test-results/report.csv';
await download.saveAs(savePath);
const content = fs.readFileSync(savePath, 'utf-8');
expect(content).toContain('Name,Email,Status');
expect(content).toContain('Jane Doe,jane@example.com,Active');
const stats = fs.statSync(savePath);
expect(stats.size).toBeGreaterThan(100);
});
test('download triggered by a link', async ({ page }) => {
await page.goto('/files');
const downloadPromise = page.waitForEvent('download');
await page.getByRole('link', { name: 'Download invoice' }).click();
const download = await downloadPromise;
expect(download.suggestedFilename()).toMatch(/invoice-\d+\.pdf/);
const tempPath = await download.path();
expect(tempPath).toBeTruthy();
});
Configuring Download Paths
Use when: You need downloads to go to a specific directory, or you need to disable the download dialog prompt.
Avoid when: Default temp paths via download.path() or download.saveAs() are sufficient.
TypeScript
// playwright.config.ts — global download behavior
import { defineConfig } from '@playwright/test';
export default defineConfig({
use: {
// Accept all downloads without prompting
acceptDownloads: true, // default is true
},
});
import { test, expect } from '@playwright/test';
import fs from 'fs';
import path from 'path';
// Per-test download directory via a custom fixture
const downloadTest = test.extend<{ downloadDir: string }>({
downloadDir: async ({}, use, testInfo) => {
const dir = path.join('test-results', 'downloads', testInfo.title.replace(/\s+/g, '-'));
fs.mkdirSync(dir, { recursive: true });
await use(dir);
},
});
downloadTest('save downloads to organized directories', async ({ page, downloadDir }) => {
await page.goto('/exports');
const downloadPromise = page.waitForEvent('download');
await page.getByRole('button', { name: 'Export' }).click();
const download = await downloadPromise;
const savePath = path.join(downloadDir, download.suggestedFilename());
await download.saveAs(savePath);
expect(fs.existsSync(savePath)).toBe(true);
});
JavaScript
// playwright.config.js
const { defineConfig } = require('@playwright/test');
module.exports = defineConfig({
use: {
acceptDownloads: true,
},
});
const { test, expect } = require('@playwright/test');
const fs = require('fs');
const path = require('path');
const downloadTest = test.extend({
downloadDir: async ({}, use, testInfo) => {
const dir = path.join('test-results', 'downloads', testInfo.title.replace(/\s+/g, '-'));
fs.mkdirSync(dir, { recursive: true });
await use(dir);
},
});
downloadTest('save downloads to organized directories', async ({ page, downloadDir }) => {
await page.goto('/exports');
const downloadPromise = page.waitForEvent('download');
await page.getByRole('button', { name: 'Export' }).click();
const download = await downloadPromise;
const savePath = path.join(downloadDir, download.suggestedFilename());
await download.saveAs(savePath);
expect(fs.existsSync(savePath)).toBe(true);
});
File Type Validation
Use when: Testing that the application rejects invalid file types and accepts valid ones. Avoid when: The application does no client-side validation and relies entirely on server-side checks (test via API instead).
TypeScript
import { test, expect } from '@playwright/test';
test('rejects unsupported file types', async ({ page }) => {
await page.goto('/upload');
// Upload an invalid file type
await page.getByLabel('Upload image').setInputFiles({
name: 'malware.exe',
mimeType: 'application/octet-stream',
buffer: Buffer.from('fake-exe-content'),
});
await expect(page.getByText('Only JPG, PNG, and GIF files are allowed')).toBeVisible();
await expect(page.getByRole('button', { name: 'Submit' })).toBeDisabled();
});
test('accepts valid file types', async ({ page }) => {
await page.goto('/upload');
await page.getByLabel('Upload image').setInputFiles({
name: 'photo.jpg',
mimeType: 'image/jpeg',
buffer: Buffer.from('fake-jpg-content'),
});
await expect(page.getByText('photo.jpg')).toBeVisible();
await expect(page.getByRole('button', { name: 'Submit' })).toBeEnabled();
});
test('validates file size limits', async ({ page }) => {
await page.goto('/upload');
// Create a buffer that exceeds the 5MB limit
const largeBuffer = Buffer.alloc(6 * 1024 * 1024, 'x');
await page.getByLabel('Upload document').setInputFiles({
name: 'huge-file.pdf',
mimeType: 'application/pdf',
buffer: largeBuffer,
});
await expect(page.getByText('File size must be under 5MB')).toBeVisible();
});
JavaScript
const { test, expect } = require('@playwright/test');
test('rejects unsupported file types', async ({ page }) => {
await page.goto('/upload');
await page.getByLabel('Upload image').setInputFiles({
name: 'malware.exe',
mimeType: 'application/octet-stream',
buffer: Buffer.from('fake-exe-content'),
});
await expect(page.getByText('Only JPG, PNG, and GIF files are allowed')).toBeVisible();
await expect(page.getByRole('button', { name: 'Submit' })).toBeDisabled();
});
test('accepts valid file types', async ({ page }) => {
await page.goto('/upload');
await page.getByLabel('Upload image').setInputFiles({
name: 'photo.jpg',
mimeType: 'image/jpeg',
buffer: Buffer.from('fake-jpg-content'),
});
await expect(page.getByText('photo.jpg')).toBeVisible();
await expect(page.getByRole('button', { name: 'Submit' })).toBeEnabled();
});
test('validates file size limits', async ({ page }) => {
await page.goto('/upload');
const largeBuffer = Buffer.alloc(6 * 1024 * 1024, 'x');
await page.getByLabel('Upload document').setInputFiles({
name: 'huge-file.pdf',
mimeType: 'application/pdf',
buffer: largeBuffer,
});
await expect(page.getByText('File size must be under 5MB')).toBeVisible();
});
Large File Handling
Use when: Testing uploads or downloads of large files where timeouts and progress indicators matter. Avoid when: Every test. Large file tests are slow. Run them in a separate suite or tag them for nightly runs.
TypeScript
import { test, expect } from '@playwright/test';
import fs from 'fs';
import path from 'path';
test.describe('large file operations', () => {
// Increase timeout for the entire describe block
test.slow(); // Triples the default timeout
test('upload large file with progress tracking', async ({ page }) => {
await page.goto('/upload');
// Create a test file on disk (avoid Buffer.alloc for very large files)
const largePath = path.join('test-results', 'large-test-file.bin');
const stream = fs.createWriteStream(largePath);
for (let i = 0; i < 100; i++) {
stream.write(Buffer.alloc(1024 * 1024, 'a')); // 100MB total
}
stream.end();
await new Promise((resolve) => stream.on('finish', resolve));
await page.getByLabel('Upload file').setInputFiles(largePath);
// Wait for progress indicator
await expect(page.getByRole('progressbar')).toBeVisible();
// Wait for completion — extended timeout
await expect(page.getByText('Upload complete')).toBeVisible({ timeout: 120_000 });
// Cleanup
fs.unlinkSync(largePath);
});
test('download large file', async ({ page }) => {
await page.goto('/exports');
const downloadPromise = page.waitForEvent('download');
await page.getByRole('button', { name: 'Export full dataset' }).click();
const download = await downloadPromise;
const savePath = 'test-results/large-export.zip';
await download.saveAs(savePath);
// Verify file size is reasonable (at least 10MB)
const stats = fs.statSync(savePath);
expect(stats.size).toBeGreaterThan(10 * 1024 * 1024);
fs.unlinkSync(savePath);
});
});
JavaScript
const { test, expect } = require('@playwright/test');
const fs = require('fs');
const path = require('path');
test.describe('large file operations', () => {
test.slow();
test('upload large file with progress tracking', async ({ page }) => {
await page.goto('/upload');
const largePath = path.join('test-results', 'large-test-file.bin');
const stream = fs.createWriteStream(largePath);
for (let i = 0; i < 100; i++) {
stream.write(Buffer.alloc(1024 * 1024, 'a'));
}
stream.end();
await new Promise((resolve) => stream.on('finish', resolve));
await page.getByLabel('Upload file').setInputFiles(largePath);
await expect(page.getByRole('progressbar')).toBeVisible();
await expect(page.getByText('Upload complete')).toBeVisible({ timeout: 120_000 });
fs.unlinkSync(largePath);
});
test('download large file', async ({ page }) => {
await page.goto('/exports');
const downloadPromise = page.waitForEvent('download');
await page.getByRole('button', { name: 'Export full dataset' }).click();
const download = await downloadPromise;
const savePath = 'test-results/large-export.zip';
await download.saveAs(savePath);
const stats = fs.statSync(savePath);
expect(stats.size).toBeGreaterThan(10 * 1024 * 1024);
fs.unlinkSync(savePath);
});
});
Decision Guide
| Scenario | Approach | Key API |
|---|---|---|
Standard <input type="file"> |
setInputFiles() on the locator |
locator.setInputFiles(path) |
| Hidden file input | Find the input even if hidden, call setInputFiles() |
page.locator('input[type="file"]').setInputFiles() |
| Custom button opens file picker | Listen for filechooser event before clicking |
page.waitForEvent('filechooser') |
| Drag-and-drop zone with no input | Dispatch drop event with DataTransfer |
locator.dispatchEvent('drop', ...) |
| DnD zone with hidden input fallback | Prefer setInputFiles() on the hidden input |
Check input[type="file"] count first |
| Multiple files at once | Pass array to setInputFiles() |
setInputFiles([path1, path2]) |
| In-memory test file (no disk) | Pass object with name, mimeType, buffer |
setInputFiles({ name, mimeType, buffer }) |
| Download — verify filename | download.suggestedFilename() |
page.waitForEvent('download') |
| Download — verify content | download.saveAs() then read with fs |
fs.readFileSync() |
| Download — temp file only | download.path() returns temp location |
Auto-deleted after test |
| Large file upload/download | Use test.slow(), increase assertion timeouts |
{ timeout: 120_000 } |
Anti-Patterns
| Don't Do This | Problem | Do This Instead |
|---|---|---|
await page.waitForTimeout(3000) after upload |
Arbitrary delay; flaky | await expect(page.getByText('Upload complete')).toBeVisible() |
await page.setInputFiles('#file', path) using CSS selector |
Fragile selector; breaks on ID changes | await page.getByLabel('Upload').setInputFiles(path) |
| Clicking download then immediately reading the file | Race condition; file may not be written yet | Use page.waitForEvent('download') then download.saveAs() |
Creating large test files in beforeAll and never cleaning up |
Fills disk in CI, slows down subsequent runs | Clean up in afterAll or use fixture teardown |
Using page.on('filechooser') for every upload |
Unnecessary complexity when <input type="file"> exists |
Use setInputFiles() directly |
| Hardcoding absolute file paths | Breaks across machines and CI | Use path.join(__dirname, ...) or relative to project root |
| Testing file upload with empty buffer | Does not test real validation behavior | Use realistic file content or minimum valid file size |
Using download.path() for permanent storage |
Temp files are cleaned up after test context closes | Use download.saveAs() for permanent paths |
| Uploading real 100MB files in every test run | Slows entire suite, wastes CI resources | Tag large file tests separately; run on schedule, not every PR |
Troubleshooting
"FileChooser event was not emitted"
Cause: The click did not open a native file picker dialog. The upload component may use a different mechanism.
// Debug: check if there is a hidden <input type="file"> you can target directly
const fileInputCount = await page.locator('input[type="file"]').count();
console.log(`Found ${fileInputCount} file inputs`);
// If input exists, skip the file chooser approach entirely
if (fileInputCount > 0) {
await page.locator('input[type="file"]').setInputFiles('fixtures/file.pdf');
}
"Download event was not emitted"
Cause: The link opens in a new tab or navigates to the file URL instead of triggering a download.
// Fix 1: Ensure acceptDownloads is true in config
// Fix 2: Check if the link opens a new tab — handle it as a new page
const pagePromise = page.context().waitForEvent('page');
await page.getByRole('link', { name: 'Download' }).click();
const newPage = await pagePromise;
// Then wait for the download event on the new page
const download = await newPage.waitForEvent('download');
Upload works locally but fails in CI
Cause: File paths are wrong in CI, or the fixture files are not included in the repo/build.
// Fix: always resolve paths relative to the test file
import path from 'path';
const fixturePath = path.join(__dirname, '..', 'fixtures', 'test-file.pdf');
// Verify the file exists before uploading
import fs from 'fs';
if (!fs.existsSync(fixturePath)) {
throw new Error(`Fixture file missing: ${fixturePath}`);
}
setInputFiles does nothing — no file appears
Cause: The input element is detached, inside a Shadow DOM, or in an iframe.
// Check for iframe
const frame = page.frameLocator('iframe[title="Upload"]');
await frame.locator('input[type="file"]').setInputFiles('fixtures/file.pdf');
// Check for Shadow DOM — Playwright pierces open shadow roots automatically
// but the input may be in a closed shadow root (rare). Use the file chooser approach instead.
Related
- core/locators.md -- locator strategies for finding upload/download elements
- core/assertions-and-waiting.md -- assertion patterns for verifying upload/download results
- core/fixtures-and-hooks.md -- creating reusable download directory fixtures
- core/network-mocking.md -- mocking upload endpoints for faster tests
- core/error-and-edge-cases.md -- testing upload failure states and error handling