Tower Research Capital Playwright Testing Interview Questions & Answers

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.

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

In a fixture or beforeEach, call the API (request.post) to create the user or order, use it in the UI test, then delete it in teardown. It is faster and more reliable than creating data through the UI.

Use environment variables or .env files, a baseURL in config, API calls for setup and cleanup, and unique data per run.

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

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

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

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

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.

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.

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

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

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

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.

Use device descriptors such as devices['iPhone 13'] in a project config to emulate viewport, user agent and touch.

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();

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

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

page.route('**/api/items', route => route.fulfill({ json: [...] })) intercepts and replies with test data; route.abort() simulates failures.

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.

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

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

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

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.

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

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

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

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

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

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

TypeScript + POM + custom fixtures, environment configs, API helpers for test data, tags like @smoke, sharding across CI machines, retries with traces, HTML/Allure reports, lint and review rules.

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

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

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

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

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.

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

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

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

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.

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.

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

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.

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

Auto-waiting, a built-in test runner, Chromium/Firefox/WebKit with one API, network interception, the trace viewer and parallel runs out of the box — usually faster and less flaky.

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

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

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

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.

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

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

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

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

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

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

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

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

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.

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

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

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

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

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

Use --debug or the Inspector, page.pause(), UI mode, the trace viewer and headed runs with slowMo.