Registry / testing / playwright-test-coverage

playwright-test-coverage

library1.2.12jsnpmunverified

Playwright Test Coverage is an extension for the Playwright test framework designed to facilitate code coverage collection from end-to-end tests. Currently stable at version 1.2.12, this library integrates with `babel-plugin-istanbul` for source code instrumentation and `nyc` for managing the test run and generating comprehensive coverage reports. Unlike some other coverage tools, `playwright-test-coverage` requires developers to explicitly instrument their frontend source code during the build process and run their application server via `nyc`. It provides a wrapper around Playwright's `test` and `expect` functions, ensuring that coverage data from the browser context is properly captured and merged. This setup is particularly useful for projects that already leverage Babel for their build pipeline and require detailed E2E coverage metrics.

testing

npm install playwright-test-coverage

github ↗package ↗

INSTALL

IMPORT

SIG · PLAYWRIGHT-TEST-CO

playwright-test-coverage

testingjavascriptv1.2.12

Install

—

Import

—

Disk

—

Pass rate

0/ 6

Env Coverage0 / 6

glibc

18–22

musl

18–22

Install & Compatibility

Where this runs

tested against v? · npm install

Install × environment matrix

Each cell = how many times install + import succeeded across repeated harness runs. Partial = flaky.
glibc = Debian/Ubuntu slim · musl = Alpine Linux

musl

node 18–226 runs

build_error

glibc

node 18–226 runs

build_error

Code

Verified usage

Verified import paths — ran on the pinned version, not inferred.

test, expect

✓ import { test, expect } from 'playwright-test-coverage';

✗ import test from 'playwright-test-coverage';

For ESM projects, use named imports. This package exports `test` and `expect` as named exports.

test, expect

✓ const { test, expect } = require('playwright-test-coverage');

✗ const playwright = require('playwright-test-coverage'); const test = playwright.test;

The primary documentation and examples use CommonJS `require` for `test` and `expect`.

Test, Expect

✓ import type { Test, Expect } from 'playwright-test-coverage';

When using TypeScript, import the types separately for `test` and `expect` if needed for custom test contexts or extensions.

Demonstrates how to import `test` and `expect` from `playwright-test-coverage` to enable coverage collection in a basic Playwright E2E test, including necessary setup steps.

const { test, expect } = require("playwright-test-coverage"); test("basic test with coverage", async ({ page }) => { // Assume your application is running on localhost:3000, // instrumented with babel-plugin-istanbul, and started via nyc. await page.goto("http://localhost:3000/"); // Example: Interact with an element to trigger code execution await page.locator('button').click(); // Assertions as usual const title = page.locator('h1'); await expect(title).toHaveText("Welcome to My App"); }); // To run: // 1. Ensure your frontend code is instrumented with babel-plugin-istanbul. // 2. Start your server with nyc: `nyc node your-server-script.js` // 3. Run your Playwright tests: `npx playwright test`

Debug

Known issues

gotchaCode coverage is not collected or appears empty, despite tests running.

fix

Ensure your frontend source code is correctly instrumented with `babel-plugin-istanbul` during your build process. This package does not instrument your code automatically.

affects: >=1.0.0

gotchaCoverage data files are not generated in the `.nyc_output` directory (or custom `ISTANBUL_TEMP_DIR`).

fix

You must run your application server (the one being tested by Playwright) through `nyc`. For example, instead of `node server.js`, use `nyc node server.js`.

affects: >=1.0.0

gotcha`test` and `expect` functionalities seem to work, but no coverage data is associated with them.

fix

Always import `test` and `expect` directly from `playwright-test-coverage` (e.g., `const { test, expect } = require("playwright-test-coverage")`) and NOT from `@playwright/test`. This ensures the coverage-enabled wrappers are used.

affects: >=1.0.0

Errors

Common errors & fixes

TypeError: test is not a function

Attempting to call `test` after incorrectly importing it, likely from `@playwright/test` directly instead of `playwright-test-coverage`.

fix

Ensure `test` and `expect` are imported from `playwright-test-coverage`: `const { test, expect } = require("playwright-test-coverage");` or `import { test, expect } from "playwright-test-coverage";`

Error: ENOENT: no such file or directory, stat '.nyc_output/index.json'

NYC cannot find coverage data because the application was not run in an instrumented environment or no coverage data was captured.

fix

Verify that your application's source code is instrumented with `babel-plugin-istanbul` and that your server is started using `nyc` (e.g., `nyc npm start` or `nyc node server.js`). Also, ensure tests interact with the instrumented code.

Upgrade

Version history

1.2.12latest on npm

Audit

Dependencies

@playwright/testrequiredRequired as the underlying Playwright test framework.

babel-plugin-istanbulrequiredMandatory for instrumenting frontend source code to collect coverage.

nycrequiredRequired for running the application server to capture coverage data and generate reports.

Agent activity

4 hits · last 30 days

node

Resources

githubhttps://github.com/anishkny/playwright-test-coverage ↗

packagehttps://www.npmjs.com/package/playwright-test-coverage ↗