Playwright

Installing browsers for playwright under NixOS

Normally, at first run, playwright will tell you to run playwright install. The purpose of this is to install browsers for you that it can then use for testing. The installation itself will technically work. Unfortunately, the installed browsers will not be suitable to be used inside NixOS. This is due to the fact that dependencies will not be at places where the browsers expect them to be. To mitigate this problem, nixpkgs has a package called playwright-driver.browsers. Before you start your script, make sure to set

export PLAYWRIGHT_BROWSERS_PATH=/path/to/drivers

You can for example put this shell.nix in the directory with your playwright tests:

{ pkgs ? import <nixpkgs> {} }:
  pkgs.mkShell {
    nativeBuildInputs = with pkgs; [
      vscode
      playwright-driver.browsers
    ];

    shellHook = ''
      export PLAYWRIGHT_BROWSERS_PATH=${pkgs.playwright-driver.browsers}
      export PLAYWRIGHT_SKIP_VALIDATE_HOST_REQUIREMENTS=true
    '';
}

You can then just run nix-shell --run "code ." to open Visual Studio Code in that directory.

Don't forget to install the Playwright Test for VSCode extension in Visual Studio Code.

Then you should be able to run your tests in Visual Studio Code.

Note: Keep in mind that you need to use the same version of playwright in your node playwright project as in your nixpkgs, or else playwright will try to use browsers versions that aren't installed!

Using Devenv

With Devenv you can also set certain environment variables and pin packages to make playwright work. Again, make sure to pin to the same version of playwright in devenv.yaml and package.json!

devenv.nix

{ pkgs, lib, config, inputs, ... }:

let
  pkgs-playwright = import inputs.nixpkgs-playwright { system = pkgs.stdenv.system; };
  browsers = (builtins.fromJSON (builtins.readFile "${pkgs-playwright.playwright-driver}/browsers.json")).browsers;
  chromium-rev = (builtins.head (builtins.filter (x: x.name == "chromium") browsers)).revision;
in
{
  # https://devenv.sh/basics/
  env = {
    PLAYWRIGHT_BROWSERS_PATH = "${pkgs-playwright.playwright.browsers}";
    PLAYWRIGHT_SKIP_VALIDATE_HOST_REQUIREMENTS = true;
    PLAYWRIGHT_NODEJS_PATH = "${pkgs.nodejs}/bin/node";
    PLAYWRIGHT_LAUNCH_OPTIONS_EXECUTABLE_PATH = "${pkgs-playwright.playwright.browsers}/chromium-${chromium-rev}/chrome-linux/chrome";
  };

  # https://devenv.sh/packages/
  packages = with pkgs; [
    just
    nodejs
  ];

  # https://devenv.sh/languages/
  languages.javascript.enable = true;

  dotenv.disableHint = true;
  cachix.enable = false;

  # https://devenv.sh/scripts/
  scripts.intro.exec = ''
    playwrightNpmVersion="$(npm show @playwright/test version)"
    echo "❄️ Playwright nix version: ${pkgs-playwright.playwright.version}"
    echo "📦 Playwright npm version: $playwrightNpmVersion"

    if [ "${pkgs-playwright.playwright.version}" != "$playwrightNpmVersion" ]; then
        echo "❌ Playwright versions in nix (in devenv.yaml) and npm (in package.json) are not the same! Please adapt the configuration."
    else
        echo "✅ Playwright versions in nix and npm are the same"
    fi

    echo
    env | grep ^PLAYWRIGHT
  '';

  enterShell = ''
    intro
  '';

  # See full reference at https://devenv.sh/reference/options/
}

devenv.yaml

# yaml-language-server: $schema=https://devenv.sh/devenv.schema.json
inputs:
  nixpkgs:
    url: github:NixOS/nixpkgs/nixos-unstable
  # Currently pinned to: playwright@1.52.0
  # See https://search.nixos.org/packages?channel=unstable&from=0&size=50&sort=relevance&type=packages&query=playwright
  nixpkgs-playwright:
      url: github:NixOS/nixpkgs/979daf34c8cacebcd917d540070b52a3c2b9b16e

package.json

{
  "name": "e2e-tests-ng",
  "version": "1.0.0",
  "main": "index.js",
  "license": "MIT",
  "devDependencies": {
    "@playwright/test": "1.52.0",
    "eslint": "^8.41.0"
  },
  "engines": {
    "node": ">=18.0.0"
  },
  "scripts": {
    "playwright:test": "playwright test",
    "playwright:test:ui": "playwright test --ui",
    "playwright:install": "playwright install",
    "lint": "eslint ."
  },
  "dependencies": {
    "dotenv": "^16.0.3",
    "jsrsasign": "^11.0.0"
  }
}