@dnb/eufemia/docs/contribute/faq.md

DNB Eufemia Design System UI Library

---
title: 'FAQ'
version: 11.3.0
generatedAt: 2026-05-19T08:46:50.015Z
checksum: 090b7d977ba4be5e2c4c04d199a30a4048416c59f443a56985df2f80629d9c40
---

# Frequently Asked Questions (FAQ)

## Visual tests and Vitest browser mode

Screenshot tests run with [Vitest browser mode](https://vitest.dev/guide/browser/) and use Playwright as the browser provider under the hood. The helper in `core/vitest-screenshots/` drives a single Firefox page per worker against the running portal on `http://localhost:8000`. The screenshot config sets `fileParallelism: true`, so test files run in parallel across workers while tests inside a file run sequentially on the same page.

### Installing screenshot browser

For running screenshot tests (visual tests), a headless Firefox browser is needed.

In normal circumstances, the browser will be installed automatically via `yarn install` – but to either upgrade to a newer version, or to wipe out existing versions and run the install manually, you can run these commands, depending on your needs:

```
yarn workspace @dnb/eufemia playwright uninstall --all
yarn workspace @dnb/eufemia add -D @playwright/test
yarn workspace @dnb/eufemia playwright install firefox

yarn workspace dnb-design-system-portal playwright uninstall --all
yarn workspace dnb-design-system-portal add -D @playwright/test
yarn workspace dnb-design-system-portal playwright install firefox
```

#### Alternative install: skip authentication

However, since Node.js and corporate proxies do not enjoy each other's company, this might
fail with an `Error: unable to get local issuer certificate` error. In that case, your only
option might be to disable all authentication for this command.

```
NODE_TLS_REJECT_UNAUTHORIZED=0 yarn workspace @dnb/eufemia playwright install firefox
```

#### Alternative install: manually

Or, in the very worst case, you can manually download the zip file that `yarn workspace 
@dnb/eufemia playwright install firefox` attempts to download, and extract the file
("Nightly" for Firefox) to the folder indicated when `yarn test:screenshots` fails.

## How can I run all screenshot tests without stopping on first failure?

By default, CI runs only affected screenshot tests based on changed files and reverse dependencies. If a global style change is detected, all screenshot tests are run.

To force all screenshot tests and continue after failures, include `--run-all` in your commit message:

```bash
git commit -m "feat: implement new feature --run-all"
```

This disables `--bail` and runs all screenshot tests, so you can see all visual differences at once.

The CI/CD pipeline automatically detects this flag and adjusts the test behavior accordingly.

### What dies `build:mini` do?

When running `build:mini` scripts, the build will be faster and the output will be smaller. It's used for the CI/CD pipeline to build the package for the Sandbox or documentation preview.

## Dependency issues

### ESLint compat patch

- We patch `eslint-plugin-compat` to always report APIs, even inside `if` statements. The patch lives in `.yarn/patches/` and is referenced from `packages/dnb-eufemia/package.json` as `patch:eslint-plugin-compat@npm:*`. If you reinstall dependencies, keep the patch or reapply it with `yarn patch-commit`.

### Jest

- jsdom [v21](https://github.com/jsdom/jsdom/releases/tag/21.0.0) changed `window`, `document`, `location`, and top properties of Window to be non-configurable, which made it impossible to mock `window.location` via `Object.defineProperty` in Jest. Jest 30 with `jest-environment-jsdom` bundles jsdom v26. Tests that need to manipulate the URL now use `window.history.replaceState` instead of overriding `window.location`.

### Babel

- Due to this bug: https://github.com/babel/babel/issues/11394 we add `.png,.snap` so they do not get copied: `--extensions '.js,.ts,.tsx,.png,.snap'`