Python - Video Recording Selenium Web UI Tests

Overview

This article shows how to create a video recording of Selenium WebDriver tests on Windows using Python. The code will use the Selenium Python bindings along with pytest. If you are unfamiliar with those, you will have to RTFM on your own. The screen recording is done with ffmpeg, a popular cross-platform open source video editing/recording program.

Some caveats

• This code only works on Windows. You can use ffmpeg on other platforms, but you will need to use different capture filters and command line arguments.
• This approach records your local desktop, so it won’t work with browsers running in headless mode or running remotely via Selenium Grid.
• To run the example code, you need to have Python installed (along with the selenium and pytest packages), and ffmpeg installed and available in your PATH.

Code examples

Tests are recorded using a function scoped fixture. When this fixture is used in a test, it will start ffmpeg in a background process, and stop the recording when the test completes. Each video is saved in a seprate file using the test’s name (i.e. video_test_example.mp4). Videos are written to the current directory and overwritten each time it is run. You can alter the fixture to save them somewhere else or incorporate them in test reports. The code also adds a --record command line argument to enable recording when calling pytest.

Here is a pytest conftest.py with the recording fixture:

import signal
import shlex
import subprocess

import pytest


def pytest_addoption(parser):
    parser.addoption(
        "--record",
        action="store_true",
        help="enable video recording",
    )


@pytest.fixture
def record(request):
    if request.config.getoption("--record"):
        test_name = request.node.name
        cmd = (
            "ffmpeg -y -f gdigrab -framerate 30 -i desktop "
            f"-vcodec libx264 video_{test_name}.mp4"
        )
        proc = subprocess.Popen(
            shlex.split(cmd),
            creationflags=subprocess.CREATE_NEW_PROCESS_GROUP,
            stderr=subprocess.DEVNULL,
        )
        yield True
        proc.send_signal(signal.CTRL_BREAK_EVENT)
    else:
        yield False

Note: Windows doesn’t have good signal handling like POSIX does, so terminating the ffmpeg process normally leaves you with a corrupt video file. To work around that, we have to create a process group and send CTRL_BREAK to get it to exist cleanly.

Here is a test file has a fixture that launches a Chrome browser for each test. This driver fixture calls the record fixture. This file also has 2 example tests that use the recording driver:

import time

import pytest
from selenium import webdriver


@pytest.fixture
def driver(record):
    with webdriver.Chrome() as _driver:
        _driver.maximize_window()
        yield _driver
        if record:
            time.sleep(3)


def test_example_1(driver):
    driver.get("https://example.com")
    assert "Example Domain" in driver.title


def test_example_2(driver):
    driver.get("https://selenium.dev")
    assert "Selenium" in driver.title

Note: There is a short sleep before closing the browser when recording is enabled, so the video doesn’t end abruptly without being able to see the results in the UI.

To run these tests with recording enabled, you would call pytest with the --record argument we added: pytest --record test_recording.py. This will produce a video file for each test.