Pytest Plugin Reference

Introduction

Playwright provides a Pytest plugin to write end-to-end tests. To get started with it, refer to the getting started guide.

Usage

To run your tests, use Pytest CLI.

pytest --browser webkit --headed

If you want to add the CLI arguments automatically without specifying them, you can use the pytest.ini file:

# content of pytest.ini
[pytest]
# Run firefox with UI
addopts = --headed --browser firefox

CLI arguments

Note that CLI arguments are only applied to the default browser, context and page fixtures. If you create a browser, a context or a page with the API call like browser.new_context(), the CLI arguments are not applied.

--headed: Run tests in headed mode (default: headless).
--browser: Run tests in a different browser chromium, firefox, or webkit. It can be specified multiple times (default: chromium).
--browser-channel Browser channel to be used.
--slowmo Slows down Playwright operations by the specified amount of milliseconds. Useful so that you can see what is going on (default: 0).
--device Device to be emulated.
--output Directory for artifacts produced by tests (default: test-results).
--tracing Whether to record a trace for each test. on, off, or retain-on-failure (default: off).
--video Whether to record video for each test. on, off, or retain-on-failure (default: off).
--screenshot Whether to automatically capture a screenshot after each test. on, off, or only-on-failure (default: off).
--full-page-screenshot Whether to take a full page screenshot on failure. By default, only the viewport is captured. Requires --screenshot to be enabled (default: off).

Fixtures

This plugin configures Playwright-specific fixtures for pytest. To use these fixtures, use the fixture name as an argument to the test function.

def test_my_app_is_working(fixture_name):
    pass
    # Test using fixture_name
    # ...

Function scope: These fixtures are created when requested in a test function and destroyed when the test ends.

context: New browser context for a test.
page: New browser page for a test.
new_context: Allows creating different browser contexts for a test. Useful for multi-user scenarios. Accepts the same parameters as browser.new_context().

Session scope: These fixtures are created when requested in a test function and destroyed when all tests end.

playwright: Playwright instance.
browser_type: BrowserType instance of the current browser.
browser: Browser instance launched by Playwright.
browser_name: Browser name as string.
browser_channel: Browser channel as string.
is_chromium, is_webkit, is_firefox: Booleans for the respective browser types.

Customizing fixture options: For browser and context fixtures, use the following fixtures to define custom launch options.

browser_type_launch_args: Override launch arguments for browser_type.launch(). It should return a Dict.
browser_context_args: Override the options for browser.new_context(). It should return a Dict.

Its also possible to override the context options (browser.new_context()) for a single test by using the browser_context_args marker:

import pytest

@pytest.mark.browser_context_args(timezone_id="Europe/Berlin", locale="en-GB")
def test_browser_context_args(page):
    assert page.evaluate("window.navigator.userAgent") == "Europe/Berlin"
    assert page.evaluate("window.navigator.languages") == ["de-DE"]

Parallelism: Running Multiple Tests at Once

If your tests are running on a machine with a lot of CPUs, you can speed up the overall execution time of your test suite by using pytest-xdist to run multiple tests at once:

# install dependency
pip install pytest-xdist
# use the --numprocesses flag
pytest --numprocesses auto

Depending on the hardware and nature of your tests, you can set numprocesses to be anywhere from 2 to the number of CPUs on the machine. If set too high, you may notice unexpected behavior.

See Running Tests for general information on pytest options.

Examples

Configure typings for auto-completion

test_my_application.py
from playwright.sync_api import Page

def test_visit_admin_dashboard(page: Page):
    page.goto("/admin")
    # ...

If you're using VSCode with Pylance, these types can be inferred by enabling the python.testing.pytestEnabled setting so you don't need the type annotation.

Using multiple contexts

In order to simulate multiple users, you can create multiple BrowserContext instances.

test_my_application.py
from playwright.sync_api import Page, BrowserContext
from pytest_playwright.pytest_playwright import CreateContextCallback

def test_foo(page: Page, new_context: CreateContextCallback) -> None:
    page.goto("https://example.com")
    context = new_context()
    page2 = context.new_page()
    # page and page2 are in different contexts

Skip test by browser

test_my_application.py
import pytest

@pytest.mark.skip_browser("firefox")
def test_visit_example(page):
    page.goto("https://example.com")
    # ...

Run on a specific browser

conftest.py
import pytest

@pytest.mark.only_browser("chromium")
def test_visit_example(page):
    page.goto("https://example.com")
    # ...

Run with a custom browser channel like Google Chrome or Microsoft Edge

pytest --browser-channel chrome

test_my_application.py
def test_example(page):
    page.goto("https://example.com")

Configure base-url

Start Pytest with the base-url argument. The pytest-base-url plugin is used for that which allows you to set the base url from the config, CLI arg or as a fixture.

pytest --base-url http://localhost:8080

test_my_application.py
def test_visit_example(page):
    page.goto("/admin")
    # -> Will result in http://localhost:8080/admin

Ignore HTTPS errors

conftest.py
import pytest

@pytest.fixture(scope="session")
def browser_context_args(browser_context_args):
    return {
        **browser_context_args,
        "ignore_https_errors": True
    }

Use custom viewport size

conftest.py
import pytest

@pytest.fixture(scope="session")
def browser_context_args(browser_context_args):
    return {
        **browser_context_args,
        "viewport": {
            "width": 1920,
            "height": 1080,
        }
    }

Device emulation / BrowserContext option overrides

conftest.py
import pytest

@pytest.fixture(scope="session")
def browser_context_args(browser_context_args, playwright):
    iphone_11 = playwright.devices['iPhone 11 Pro']
    return {
        **browser_context_args,
        **iphone_11,
    }

Or via the CLI --device="iPhone 11 Pro"

Using with `unittest.TestCase`

See the following example for using it with unittest.TestCase. This has a limitation, that only a single browser can be specified and no matrix of multiple browsers gets generated when specifying multiple.

import pytest
import unittest

from playwright.sync_api import Page


class MyTest(unittest.TestCase):
    @pytest.fixture(autouse=True)
    def setup(self, page: Page):
        self.page = page

    def test_foobar(self):
        self.page.goto("https://microsoft.com")
        self.page.locator("#foobar").click()
        assert self.page.evaluate("1 + 1") == 2

Debugging

Use with pdb

Use the breakpoint() statement in your test code to pause execution and get a pdb REPL.

def test_bing_is_working(page):
    page.goto("https://bing.com")
    breakpoint()
    # ...

Deploy to CI

See the guides for CI providers to deploy your tests to CI/CD.

Introduction​

Usage​

CLI arguments​

Fixtures​

Parallelism: Running Multiple Tests at Once​

Examples​

Configure typings for auto-completion​

Using multiple contexts​

Skip test by browser​

Run on a specific browser​

Run with a custom browser channel like Google Chrome or Microsoft Edge​

Configure base-url​

Ignore HTTPS errors​

Use custom viewport size​

Device emulation / BrowserContext option overrides​

Using with unittest.TestCase​

Debugging​

Use with pdb​

Deploy to CI​