CRED Playwright Testing Interview Questions & Answers

Log in once in a setup project, save storageState to a file and reuse it in other projects or tests.

var is function-scoped and hoisted. let and const are block-scoped; const can't be reassigned (though an object it points to can change). Prefer const, then let.

Assertions like expect(locator).toBeVisible() that retry until they pass or time out, unlike one-off checks.

Use npx playwright test --shard=1/4 in each CI job and merge reports afterwards to reduce total run time.

JavaScript runs one call stack and uses queues for async work; the event loop pushes callbacks from the microtask (promises) and task queues when the stack is empty.

Record timestamps around the request or use response timing, then assert the duration is under an agreed threshold.

setInputFiles on the input for uploads; for downloads wait on page.waitForEvent('download') and save or inspect the file.

Both describe object shapes. Interfaces can be extended and merged; type aliases can also describe unions and primitives. Use interfaces for page or test-data shapes, types for unions.

test('login', async ({ page }) => { await page.goto('/login'); await page.getByLabel('Email').fill('a@b.com'); await page.getByLabel('Password').fill('secret'); await page.getByRole('button', { name: 'Login' }).click(); await expect(page.getByRole('heading', { name: 'Dashboard' })).toBeVisible(); });

Named configurations that run the same tests across different browsers, devices or environments.

npx playwright test tests/login.spec.ts, add -g "test title" to match a name, or use test.only while debugging.

Separate tests, page objects, fixtures, utilities, test data and config; use tags, projects, shared auth setup, linting, code review and a CI pipeline with sharding and reports.

Fetch tokens in a fixture with expiry tracking and refresh it when it is about to expire, keeping tests unaware of the details.

Log in once in global setup, save storageState to a JSON file and set use.storageState in the config so every test starts logged in.

Use a library such as zod or ajv to define the expected schema and parse the response to fail on missing or wrongly typed fields.

test.step groups actions into named steps in reports; annotations such as test.skip, test.fixme and test.slow communicate intent and adjust behaviour.

Set extraHTTPHeaders in the config or pass headers per request, for example Authorization: Bearer token fetched in a setup step.

locator.hover() and locator.dragTo(target) perform these actions, with auto-waiting for actionability.

POST the query and variables as JSON to the single endpoint and assert both data and errors fields in the response.

Define projects for chromium, firefox and webkit in playwright.config.ts, set workers, then run: npx playwright test

Capture the download event, save it with download.saveAs, then read the file in Node and assert on name, size or content.

const [newPage] = await Promise.all([ context.waitForEvent('page'), page.getByText('Open').click(), ]); await newPage.waitForLoadState();

Rely on auto-waiting plus a web-first assertion on the final state, disable animations in config for tests and avoid fixed timeouts.

Assert the status with expect(res.status()).toBe(200), parse res.json() and check fields, using schema validation for the structure.

Use try-catch with await, or .catch() on promises, and make sure rejected promises are never left unhandled.

TypeScript adds static types on top of JavaScript and compiles to it. Types catch errors early and give better autocomplete, which helps in larger test suites.

Both describe the shape of data. Interfaces are extendable and suit object contracts; type aliases can also model unions and primitives.

map transforms each item, filter keeps items that match a condition, and reduce combines all items into a single value.

The action runs without waiting, so the next step may run first — causing flaky failures or 'Target closed' errors. The @typescript-eslint/no-floating-promises rule catches it.

Set retries in the config or CLI and failed tests re-run in a fresh context, with trace recorded on first retry to diagnose flakiness.

A Locator is lazy, re-resolved on every action and auto-waits (recommended). An ElementHandle points to one DOM node and can go stale.

Install the allure-playwright reporter, add it in the config reporters array and generate the report from the allure-results folder in CI.

Use the official Playwright image which contains browsers and dependencies, mount the project and run npx playwright test for consistent CI environments.

Use the request fixture: const res = await request.get('/api/users'); expect(res.ok()).toBeTruthy(); const body = await res.json();

Scripts that run once before or after the whole run, for seeding data, starting services or creating authentication state.

An open-source end-to-end testing framework from Microsoft that automates Chromium, Firefox and WebKit through one API, in multiple languages.

Synchronous code runs line by line and blocks; asynchronous code starts a task and continues, handling the result later with promises or await.

Add retries with backoff for the API step, set a suitable timeout, and use mocks for non-critical dependencies.

Click to open the control, then use getByRole('option') or a text locator for the target item, instead of relying on fragile index-based selectors.

Read the next page link or IDs from earlier responses, loop until done and assert counts and uniqueness; pass IDs between calls in the same test.

click simulates a real user click with actionability checks; dispatchEvent fires a DOM event directly without those checks.

Destructuring pulls values from arrays or objects into variables; spread expands an array or object into another, useful for copying and merging config.

Placeholders for types that make reusable code type-safe, for example a helper function returning the same type of item that it receives.

Use expect(page).toHaveScreenshot() to compare with stored baselines, with thresholds and masks for dynamic regions.

Reusable setup/teardown units injected into tests (page, context, request). You can extend test with custom fixtures such as loggedInPage.

Use dotenv files per environment, read them in playwright.config and set baseURL and credentials from variables, selecting with an ENV flag.

User-facing ones: getByRole, getByText, getByLabel, getByPlaceholder and getByTestId, which are more resilient than CSS or XPath.

API testing checks services directly and is fast and stable; UI testing checks the full user experience in the browser and is slower.

beforeEach runs the same code before every test in scope; fixtures are lazy, composable and only set up what a test uses.

Use page.route to intercept the call and fulfil it with fixed JSON so tests do not depend on external systems.

Use page.frameLocator('#frame').getByRole(...) so actions work inside the iframe with auto-waiting.

A type alias describes a shape or union of values; an enum creates a named set of constants that exists at runtime.

await expect.soft(locator).toHaveText('...') records the failure but lets the test continue, so you see every mismatch in one run.

waitForSelector is a lower-level wait; locator assertions are preferred as they retry and are more readable.

obj?.a?.b safely reads nested properties and returns undefined instead of throwing if something in the chain is missing.

A short function syntax that does not have its own this and arguments, taking them from the surrounding scope.

A class receives page in its constructor, stores locators as properties and exposes actions like login(user, pass). Tests call page objects, not raw locators.

Use page.waitForResponse(res => res.url().includes('/api/orders') && res.ok()) together with the action that triggers it.

Wait for the popup event with const [popup] = await Promise.all([page.waitForEvent('popup'), page.click('a')]), then interact with popup.

Log in with request.post, call request.storageState(), and create a browser context using that state.

Playwright supports multiple browsers, tabs, languages and has auto-waiting and tracing; Selenium has the widest ecosystem; Cypress runs in-browser with a great UI but has more limits across tabs.

await page.route('**/api/users', route => route.fulfill({ status: 200, json: [{ id: 1, name: 'Test' }] }) );

Workflow: checkout → setup-node → npm ci → npx playwright install --with-deps → npx playwright test → upload playwright-report as an artifact.

await expect(page).toHaveScreenshot('home.png') compares against a baseline image; tune maxDiffPixels and mask dynamic areas like dates.

string, number, boolean, null, undefined, symbol, bigint and object (including arrays and functions).

npm is the Node package manager. package.json lists the project's dependencies and scripts, such as the command that runs the tests.