Morgan Stanley Playwright Testing Interview Questions & Answers

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.

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

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

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.

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

Create test data through API calls, verify it in the UI and clean up via API, which makes UI tests faster and more reliable.

List, dot, line, HTML, JSON and JUnit reporters, plus integrations such as Allure, configurable per environment.

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

Create a class that takes a page, defines locators as properties and exposes action methods; instantiate it in a fixture for clean tests.

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

Files run in parallel by default; set workers in the config and use test.describe.configure({ mode: 'parallel' }) for tests inside a file.

Use timeout and expect.timeout in config, test.setTimeout() for one test and test.slow() for known slower tests.

Run npm init playwright@latest, which sets up config, example tests and browsers; execute with npx playwright test.

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

Integrate axe-core through @axe-core/playwright, run an analysis on the page and assert that there are no violations.

An object describing how to find an element, re-evaluated on every action so it always targets the current DOM.

Send invalid payloads or missing auth and assert 400, 401 or 404 codes and the error message bodies.

A browser is the engine instance; a context is an isolated session (cookies, storage); a page is a tab inside a context.

The object behind the request fixture that holds base URL, headers and cookies, and can share cookies with a browser context.

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

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

Use request.post with multipart: { file: { name, mimeType, buffer } } and assert the response and stored file details.

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

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

const [download] = await Promise.all([ page.waitForEvent('download'), page.getByText('Export').click(), ]); await download.saveAs('reports/file.csv');

Tag tests (in the title or with { tag: '@smoke' }) and run: npx playwright test --grep @smoke (use --grep-invert to exclude).

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

await request.post('/api/users', { data: { name: 'Asha' } }) automatically sets JSON headers and serialises the payload.

Syntax over Promises: an async function returns a Promise and await pauses until it resolves. Every Playwright action returns a Promise, so you await each step.

undefined means a variable has not been assigned; null is an intentional empty value.

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

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

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

Functions that take other functions as arguments or return them, such as map, filter and reduce, or a helper that wraps retry logic around a test step.

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

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

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

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

Run in parallel with sharding, reuse authentication state, set up data through APIs, avoid unnecessary waits, run smoke on every commit and the full suite nightly.

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

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.

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

npx playwright codegen records user actions and generates test code with suggested locators, handy for starting tests.

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

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

It records screenshots, DOM snapshots, network calls and actions per step so you can replay a failed run and see exactly what happened.

A function that remembers variables from its outer scope even after that scope has finished. They are used for private state and factory helpers.

Register page.on('dialog', d => d.accept()) before the action triggers the dialog.

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

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

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

Set them in the context options (geolocation, permissions, timezoneId, locale) to simulate users from other regions.

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

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

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.

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

Define an interface for the payload, cast or validate the parsed JSON to it (for example with zod), and use that type in assertions to catch shape changes.

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.

Add tags in the title (@smoke) or use the tag option, and run with --grep @smoke or --grep-invert.

page.screenshot() for captures and config options use: { screenshot: 'only-on-failure', video: 'retain-on-failure' } for automatic evidence.

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.

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.

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.

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

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

all waits for every promise and rejects on the first failure; allSettled waits for all and reports each outcome; race settles with the first one to finish.

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

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.

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.

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

Fixtures set up and tear down test dependencies. Extend with test.extend({ loggedInPage: async ({ page }, use) => { ...; await use(page); } }).

Strings in backticks that allow embedded expressions like `Hello ${name}` and multi-line text, useful for building dynamic locators and URLs.

Playwright locators pierce open shadow roots by default, so getByRole and CSS locators work without special handling.

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

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

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