Playwright enables reliable end-to-end testing for modern web apps - any browser, any platform, one API.

Read on to get it installed and running on nixos.

Installation⌗

Playwright was created specifically to accommodate the needs of end-to-end testing. Playwright supports all modern rendering engines including Chromium, WebKit, and Firefox.

The Playwright library can be used as a general purpose browser automation tool, providing a powerful set of APIs to automate web applications, for both sync and async Python.

To begin, create flake.nix file with the following content:

{
  description = "A dev shell for running playwright e2e tests";

  inputs.nixpkgs.url = "github:nixos/nixpkgs/nixpkgs-unstable";

  outputs = { self, nixpkgs }:
    let
      system = "x86_64-linux";
      pkgs = import nixpkgs { inherit system; };
    in
    {
      devShells.${system}.default = pkgs.mkShell {
        buildInputs = with pkgs; [
          playwright-driver
          python312Full
          python312Packages.playwright
          python312Packages.pip
          python312Packages.pytest
        ];

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

then enter the development shell:

nix develop

and create and activate new virtual env:

python -m venv .venv
source .venv/bin/activate

Put the pip requirements in a file named requirements.txt with the following content:

pytest-playwright

and install requirements with:

pip install -r requirements.txt

Create test(s)⌗

We are now ready to start writing tests with Python. Create a new test file with the following content:

# example_test.py
import re
from playwright.sync_api import Page, expect

def test_has_title(page: Page):
    page.goto("https://google.co.uk/about")
    # Expect a title "to contain" a substring.
    expect(page).to_have_title(re.compile("About Google"))

Run test(s)⌗

From the terminal:

pytest --tracing on

You should see some output in the terminal about the number of tests ran, passed or failed etc. Given that you have passed the --tracing flag when running the tests, the traces for the tests can be found in the test-results/ directory and these can be viewed by running another command in the terminal:

playwright show trace test-results/test-example-py-test-has-title-chromium/trace.zip

Note how the trace includes the test and the browser as part of the directory structure. chromium is the default browser here.

That is a brief overview of getting started with Playwright for e2e testing. It can do so much more. Read more in the official docs.