[BUG] Playwright produces zero-bytes .webm videos

[paunovic]

Context:

• Playwright Version: Version 1.15.0-1631797286000
• Operating System: ubuntu/bionic64
• Node.js version: v12.16.1
• Browser: All
• Extra: running inside virtualbox vm, host OS is Windows 10.

Code Snippet

@pytest.fixture(autouse=True)
def browser_context_args(browser_context_args: dict) -> dict:

    browser_context_args = {
        **browser_context_args,
        "viewport": {
            "width": 1920,
            "height": 1080,
        },
        "device_scale_factor": 2,
        "record_video_size": {
            "width": 800,
            "height": 600,
        },
    }

    return browser_context_args

Describe the bug

I am running Playwright + Python + pytest-playwright with following arguments:

pytest --tracing retain-on-failure --screenshot only-on-failure --video retain-on-failure

On error, tracing and screenshots are saved fine, however videos come out as zero bytes .webm files.

[paunovic]

Looks like a bug with tempfile library where tempfile.Directory() returns slightly incorrect path, resulting videos not to be moved from artifacts dir to output dir.

[JoelEinbinder]

Transferred to the playwright-pytest repo. Looks like a bug with our pytest fixtures. PRs welcome if you know how to fix it, otherwise @mxschmitt can you take a look?

[mxschmitt]

@paunovic sorry for the late reply. Do you have a full example somewhere (e.g. GitHub repo)? I tried to confirm it and reproduce it locally, but for me it seems working as intended.

[paunovic]

Hi, here is minimal reproducible example:

conftest.py:

import os
import tempfile
from typing import Any, Callable, Dict, Generator, List

import pytest
from playwright.sync_api import (
    Browser,
    BrowserContext,
    Page,
    Playwright,
    sync_playwright,
)


artifacts_folder = tempfile.TemporaryDirectory(prefix="playwright-pytest-")
print(f"{artifacts_folder.name=}")


@pytest.fixture()
def browser_context_args(
    pytestconfig: Any,
    playwright: Playwright,
) -> Dict:
    context_args = {"record_video_dir": artifacts_folder}
    return context_args


@pytest.fixture(scope="session")
def playwright() -> Generator[Playwright, None, None]:
    pw = sync_playwright().start()
    yield pw
    pw.stop()


@pytest.fixture(scope="session")
def browser(launch_browser: Callable[[], Browser]) -> Generator[Browser, None, None]:
    browser = launch_browser()
    yield browser
    browser.close()


@pytest.fixture
def context(
    browser: Browser,
    browser_context_args: Dict,
    pytestconfig: Any,
) -> Generator[BrowserContext, None, None]:
    pages: List[Page] = []
    context = browser.new_context(**browser_context_args)
    context.on("page", lambda p: pages.append(p))

    yield context

    context.close()

    for page in pages:
        video = page.video
        video_path = str(video.path())
        print(f"{video_path=}")
        file_name = os.path.basename(video_path)
        video.save_as(f"/tmp/{file_name}")


@pytest.fixture
def page(context: BrowserContext, base_url: str) -> Generator[Page, None, None]:
    page = context.new_page()
    yield page

test_bug.py:

from playwright.sync_api import Page


def test_bug(page: Page):
    page.goto("https://playwright.dev/python/docs/intro/")

Running on Python 3.8.1, ubuntu/bionic64. If I change following line:

context_args = {"record_video_dir": artifacts_folder}

to:

context_args = {"record_video_dir": artifacts_folder.name}

It starts working.

[mxschmitt]

Ohhh good catch! Thats the fix for it: #83. Will release it shortly.

[paunovic]

Just for posterity, the bug that I was encountering few weeks ago when I initially opened this issue was different - TemporaryDirectory was returning underscore instead of dash at one place in the string for some reason, compared to video.path(). Looks like there are few buggy behaviours. Personally I refactored my fixtures away from TemporaryDirectory.

Oh and there's also a typo in temp directory name, playwight.