Pytest Plugin for Visual Testing with Playwright

Based on pixelmatch-py image comparison library.

Expands assert_snapshot fixture from pytest-playwright-snapshot library

Main Features:

• snapshots creation on the first run
• visual review of mismatches
• failing on --update-snapshots to make users manually review images
• snapshot name is optional, test_name[browser][os].png is auto-generated by default
• updated folder structure: snapshots/file_name/test_name/test_name[browser][os].png

Installation

$ pip install pytest-playwright-visual

Usage

This plugin provides a assert_snapshot fixture which is used to create snapshots and compare it.

Example:

def test_myapp(page, assert_snapshot):
    page.goto("https://example.com")
    assert_snapshot(page.screenshot())

Then, run pytest:

$ pytest

The first time you run pytest, snapshots will be created, and you will get the error:

Failed: --> New snapshot(s) created. Please review images

The next run, the snapshots comparison will take place.

To update snapshots, run:

$ pytest --update-snapshots

After updating, tests will fail and you will need to review images.

In case of a mismatch, snapshot_tests_failures folder will be created with Actual_.., Expected_.. and Diff_.. images generated.

Folder Structure Example

API

assert_snapshot(page.screenshot(), threshold: float = 0.1, name='test_name[browser][os].png', fail_fast=False)

• threshold - sets the threshold for the comparison of the screenshots:0 to 1. Default is 0.1
• name - .png extensions only. Default is test_name[browser][os].png (recommended)
• fail_fast - If True, will fail after first different pixel. False by default

License

Apache 2.0 LICENSE