Emulation | Playwright Python

Introduction​

With Playwright you can test your app on any browser as well as emulate a real device such as a mobile phone or tablet. Simply configure the devices you would like to emulate and Playwright will simulate the browser behavior such as "userAgent", "screenSize", "viewport" and if it "hasTouch" enabled. You can also emulate the "geolocation", "locale" and "timezone" for all tests or for a specific test as well as set the "permissions" to show notifications or change the "colorScheme".

Devices​

Playwright comes with a registry of device parameters using playwright.devices for selected desktop, tablet and mobile devices. It can be used to simulate browser behavior for a specific device such as user agent, screen size, viewport and if it has touch enabled. All tests will run with the specified device parameters.

from playwright.sync_api import sync_playwright, Playwright
def run(playwright: Playwright):
    iphone_13 = playwright.devices['iPhone 13']
    browser = playwright.webkit.launch(headless=False)
    context = browser.new_context(
        **iphone_13,
    )
with sync_playwright() as playwright:
    run(playwright)

Note: Pre-configured devices assume a specific platform. For example, "Desktop Chrome" will provide a Windows-specific user agent string.

If you would like to use the user agent specific to the platform that is running the tests, we recommend unsetting the user agent property.

desktop_chrome = playwright.devices["Desktop Chrome"]
context = browser.new_context(**desktop_chrome, user_agent=None)

Viewport​

The viewport is included in the device but you can override it for some tests with page.set_viewport_size().

Test file:

The same works inside a test file.

# Create context with given viewport
context = browser.new_context(
  viewport={ 'width': 1280, 'height': 1024 }
)
# Resize viewport for individual page
page.set_viewport_size({"width": 1600, "height": 1200})
# Emulate high-DPI
context = browser.new_context(
  viewport={ 'width': 2560, 'height': 1440 },
  device_scale_factor=2,
)

isMobile​

Whether the meta viewport tag is taken into account and touch events are enabled.

context = browser.new_context(
  is_mobile=False
)

Locale & Timezone​

Emulate the browser Locale and Timezone which can be set globally for all tests in the config and then overridden for particular tests.

context = browser.new_context(
  locale='de-DE',
  timezone_id='Europe/Berlin',
)

Permissions​

Allow app to show system notifications.

context = browser.new_context(
  permissions=['notifications'],
)

Allow notifications for a specific domain.

context.grant_permissions(['notifications'], origin='https://skype.com')

Revoke all permissions with browser_context.clear_permissions().

context.clear_permissions()

Geolocation​

Grant "geolocation" permissions and set geolocation to a specific area.

context = browser.new_context(
  geolocation={"longitude": 41.890221, "latitude": 12.492348},
  permissions=["geolocation"]
)

Change the location later:

context.set_geolocation({"longitude": 48.858455, "latitude": 2.294474})

Note you can only change geolocation for all pages in the context.

Emulate the users "colorScheme". Supported values are 'light' and 'dark'. You can also emulate the media type with page.emulate_media().

# Create context with dark mode
context = browser.new_context(
  color_scheme='dark' # or 'light'
)
# Create page with dark mode
page = browser.new_page(
  color_scheme='dark' # or 'light'
)
# Change color scheme for the page
page.emulate_media(color_scheme='dark')
# Change media for page
page.emulate_media(media='print')

User Agent​

The User Agent is included in the device and therefore you will rarely need to change it however if you do need to test a different user agent you can override it with the userAgent property.

context = browser.new_context(
  user_agent='My user agent'
)

Offline​

Emulate the network being offline.

context = browser.new_context(
  offline=True
)

JavaScript Enabled​

Emulate a user scenario where JavaScript is disabled.

context = browser.new_context(
  java_script_enabled=False
)