percy-selenium-python

Percy visual testing for Python Selenium.

Installation

npm install @percy/cli:

$ npm install --save-dev @percy/cli

pip install Percy selenium package:

$ pip install percy-selenium

Usage

This is an example test using the percy_snapshot function.

from percy import percy_snapshot

browser = webdriver.Firefox()
browser.get('http://example.com')
​
# take a snapshot
percy_snapshot(browser, 'Python example')

Running the test above normally will result in the following log:

[percy] Percy is not running, disabling snapshots

When running with percy exec, and your project's PERCY_TOKEN, a new Percy build will be created and snapshots will be uploaded to your project.

$ export PERCY_TOKEN=[your-project-token]
$ percy exec -- [python test command]
[percy] Percy has started!
[percy] Created build #1: https://percy.io/[your-project]
[percy] Snapshot taken "Python example"
[percy] Stopping percy...
[percy] Finalized build #1: https://percy.io/[your-project]
[percy] Done!

Configuration

percy_snapshot(driver, name[, **kwargs])

• driver (required) - A selenium-webdriver driver instance
• name (required) - The snapshot name; must be unique to each snapshot
• **kwargs - See per-snapshot configuration options

Cookies

By default the SDK sends the browser's cookies with each snapshot so Percy can load pages and assets that need a logged-in session during asset discovery. To stop sending cookies, set PERCY_DO_NOT_USE_CAPTURED_COOKIES=true. Assets behind authentication may then fail to load and snapshots can render incorrectly; the SDK logs a warning once when this is enabled.

Migrating Config

If you have a previous Percy configuration file, migrate it to the newest version with the config:migrate command:

$ percy config:migrate

Percy on Automate

Usage

This is an example test using the percy_screenshot function. percy_screenshot(driver, name, options) [ needs @percy/cli 1.27.0-beta.0+ ];

from percy import percy_screenshot

driver = webdriver.Remote("https://hub-cloud.browserstack.com/wd/hub", caps) # using automate session
driver.get('http://example.com')
​
# take a snapshot
percy_screenshot(driver, name = 'Screenshot 1')

• driver (required) - A Selenium driver instance
• name (required) - The screenshot name; must be unique to each screenshot
• options (optional) - There are various options supported by percy_screenshot to server further functionality.
  • sync - Boolean value by default it falls back to false, Gives the processed result around screenshot [From CLI v1.28.0-beta.0+]
  • full_page - Boolean value by default it falls back to false, Takes full page screenshot [From CLI v1.27.6+]
  • freeze_animated_image - Boolean value by default it falls back to false, you can pass true and percy will freeze image based animations.
  • freeze_image_by_selectors -List of selectors. Images will be freezed which are passed using selectors. For this to work freeze_animated_image must be set to true.
  • freeze_image_by_xpaths - List of xpaths. Images will be freezed which are passed using xpaths. For this to work freeze_animated_image must be set to true.
  • percy_css - Custom CSS to be added to DOM before the screenshot being taken. Note: This gets removed once the screenshot is taken.
  • ignore_region_xpaths - List of xpaths. elements in the DOM can be ignored using xpath
  • ignore_region_selectors - List of selectors. elements in the DOM can be ignored using selectors.
  • ignore_region_selenium_elements - List of selenium web-element. elements can be ignored using selenium_elements.
  • custom_ignore_regions - List of custom objects. elements can be ignored using custom boundaries. Just passing a simple object for it like below.
    • example: {"top": 10, "right": 10, "bottom": 120, "left": 10}
    • In above example it will draw rectangle of ignore region as per given coordinates.
      • top (int): Top coordinate of the ignore region.
      • bottom (int): Bottom coordinate of the ignore region.
      • left (int): Left coordinate of the ignore region.
      • right (int): Right coordinate of the ignore region.
  • consider_region_xpaths - List of xpaths. elements in the DOM can be considered for diffing and will be ignored by Intelli Ignore using xpaths.
  • consider_region_selectors - List of selectors. elements in the DOM can be considered for diffing and will be ignored by Intelli Ignore using selectors.
  • consider_region_selenium_elements - List of selenium web-element. elements can be considered for diffing and will be ignored by Intelli Ignore using selenium_elements.
  • custom_consider_regions - List of custom objects. elements can be considered for diffing and will be ignored by Intelli Ignore using custom boundaries
    • example:{"top": 10, "right": 10, "bottom": 120, "left": 10}
    • In above example it will draw rectangle of consider region will be drawn.
    • Parameters:
      • top (int): Top coordinate of the consider region.
      • bottom (int): Bottom coordinate of the consider region.
      • left (int): Left coordinate of the consider region.
      • right (int): Right coordinate of the consider region.
  • regions parameter that allows users to apply snapshot options to specific areas of the page. This parameter is an array where each object defines a custom region with configurations.
    • Parameters:

      • elementSelector (optional, only one of the following must be provided, if this is not provided then full page will be considered as region)

        • boundingBox (object): Defines the coordinates and size of the region.
          • x (number): X-coordinate of the region.
          • y (number): Y-coordinate of the region.
          • width (number): Width of the region.
          • height (number): Height of the region.
        • elementXpath (string): The XPath selector for the element.
        • elementCSS (string): The CSS selector for the element.

      • algorithm (mandatory)

        • Specifies the snapshot comparison algorithm.
        • Allowed values: standard, layout, ignore, intelliignore.

      • configuration (required for standard and intelliignore algorithms, ignored otherwise)

        • diffSensitivity (number): Sensitivity level for detecting differences.
        • imageIgnoreThreshold (number): Threshold for ignoring minor image differences.
        • carouselsEnabled (boolean): Whether to enable carousel detection.
        • bannersEnabled (boolean): Whether to enable banner detection.
        • adsEnabled (boolean): Whether to enable ad detection.

      • assertion (optional)

        • Defines assertions to apply to the region.
        • diffIgnoreThreshold (number): The threshold for ignoring minor differences.

Example Usage for regions

obj1 = {
  "elementSelector": {
    "elementCSS": ".ad-banner" 
  },
  "algorithm": "intelliignore",
  "configuration": {
    "diffSensitivity": 2,
    "imageIgnoreThreshold": 0.2,
    "carouselsEnabled": true,
    "bannersEnabled": true,
    "adsEnabled": true
  },
  "assertion": {
    "diffIgnoreThreshold": 0.4,
  }
};

# we can use the createRegion function

from percy import percy_snapshot
from percy.snapshot import (create_region)

obj2 = create_region(
    algorithm="intellignore",
    diffSensitivity=2,
    imageIgnoreThreshold=0.2,
    carouselsEnabled=True,
    adsEnabled=True,
    diffIgnoreThreshold=0.4
)

percy_snapshot(page, name="Homepage", regions=[obj1]);

Creating Percy on automate build

Note: Automate Percy Token starts with auto keyword. The command can be triggered using exec keyword.

$ export PERCY_TOKEN=[your-project-token]
$ percy exec -- [python test command]
[percy] Percy has started!
[percy] [Python example] : Starting automate screenshot ...
[percy] Screenshot taken "Python example"
[percy] Stopping percy...
[percy] Finalized build #1: https://percy.io/[your-project]
[percy] Done!

Refer to docs here: Percy on Automate

Robot Framework Support

This package includes built-in Robot Framework support. Install the additional dependencies:

$ pip install robotframework robotframework-seleniumlibrary

Then use PercyLibrary in your Robot tests:

*** Settings ***
Library    SeleniumLibrary
Library    percy.robot_library.PercyLibrary

*** Test Cases ***
Homepage Visual Test
    Open Browser    https://example.com    chrome
    Percy Snapshot    Homepage
    Percy Snapshot    Responsive    widths=375,768,1280
    Percy Snapshot    Tagged    labels=regression,v2
    Close Browser

Run with percy exec:

$ percy exec -- robot tests/

Robot Keywords

Percy Snapshot

Percy Snapshot name [widths] [min_height] [percy_css] [scope] [enable_javascript] [enable_layout] [labels] [regions]

• name (required) - The snapshot name; must be unique to each snapshot
• widths - Comma-separated responsive widths (e.g., 375,768,1280)
• min_height - Minimum screenshot height in pixels
• percy_css - Custom CSS to inject before snapshot
• scope - CSS selector to limit the snapshot area
• enable_javascript - Enable JS in Percy rendering (default: not set)
• enable_layout - Enable layout comparison mode (default: not set)
• labels - Comma-separated labels/tags (e.g., regression,homepage)
• test_case - Test case identifier
• regions - JSON string of region definitions (use Create Percy Region)
• responsive_snapshot_capture - Enable responsive capture mode

Percy Screenshot (Automate)

Percy Screenshot name [options] [ignore_region_selenium_elements] [consider_region_selenium_elements]

Create Percy Region

Create Percy Region [algorithm] [element_css] [element_xpath] [bounding_box] [padding]

${region}=    Create Percy Region    algorithm=ignore    element_css=.ad-banner
Percy Snapshot    Homepage    regions=${{json.dumps([${region}])}}

Percy Is Running

${running}=    Percy Is Running
Run Keyword If    ${running}    Percy Snapshot    Homepage

Note: Robot Framework support is optional. If robotframework is not installed, the rest of percy-selenium works unchanged.