PlayWright

Playwright is another powerful testing tool that works as part of pytest, which we can use to test the content of a webpage itself. This can include clicking links, checking the heading of a page, and reading the text of (As well as much more)

While we might think of something like our SQL and Fastapi tests as testing the behind the scenes aspects of our website, something like Playwright tests what the user actually sees and interacts with, to make sure the front end of our website behaves as expected.

Thankfully we don’t need to create a new testing document, as playwright works as part of pytest. We will need to install it though.

Making sure we’re inside our project directory and our Venv, run:

uv pip install pytest-playwright

followed by

playwright install

and then insied our testing file, we’ll want to add a new import so we can use playwright

from playwright.sync_api import Page, expect

And we’re good to start writing tests!

Playwright tests

Section titled Playwright tests

Playwright test functions should be formatted the same way as other tests you’ve been writing, starting with test_

Generally, the first thing we want to do in a playwright test is navigate to a page, we do this using

page.goto("url")

So for our development server we would use

page.goto("http://127.0.0.1:8000/")

We can then check if the page has the title we would expect it to (For our blog, this would me “My Blog”)

expect(page).to_have_title(re.compile("My Blog"))

We can also use Playwright to click a link. Say for example we had a link with the text “Click here” which leads us to a page with the title “Secret Page” writing a test for this page would look like this:

def test_secret_page(page: Page):
    page.goto("http://127.0.0.1:8000/")

    page.get_by_role("link", name="Click Here").click()

    expect(page).to_have_title(re.compile("Secret Page"))