Pytest: how to display generated report after test run?

Question

I am using pytest in combination with the pytest-html plugin which generates an HTML report after the test has run.

I am using an auto-wired session fixture to automatically open the generated HTML report in a browser:

@pytest.fixture(scope="session", autouse=True)
def session_wrapper(request):
    print('Session wrapper init...')
    yield

    # open report in browser on Mac or Windows, skip headless boxes
    if platform.system() in ['Darwin', 'Windows']:
        html_report_path = os.path.join(request.config.invocation_dir.strpath, request.config.option.htmlpath)
        open_url_in_browser("file://%s" %html_report_path)

The code above works, but not consistently, because sometimes the browser attempts to load the file before it is created which results in a file not found error, and requires a manual browser refresh in order for the report to be shown.

My understanding is that scope="session" is the widest available scope, and my assumption was that pytest-html should finish generating the report before the end of the session, but apparently that is not the case.

The question is: what would be the correct way to hook the browser report auto-launch code? Could it be that pytest-html is also hooking into the session finalizer scope? In that case how to make sure that the HTML file is open in the browser only after the file has been created?

Answer 1

Instead of using fixtures you may try using hooks.

In the past I did something interesting with them, unfortunately I don't remember if there's called at the very end of the run but probably yes

Answer 2

In your conftest.py:

import pytest

@pytest.hookimpl(trylast=True)
def pytest_configure(config):
    config._htmlfile = config._html.logfile


@pytest.hookimpl(trylast=True)
def pytest_sessionfinish(session, exitstatus):
    file = session.config._htmlfile
    # invoke the file opening in external tool
    os.system('open ' + file)

Notes:

• pytest-html writes the report in pytest_sessionfinish hook, so you will need a custom sessionfinish hook. Mark it with trylast=True to ensure your hook impl runs after pytest-html's one.
• config.option.htmlpath is what is passed via --html-path command line argument; config._html.logfile is what pytest-html actually uses as file name. It's accessible after pytest-html's configure hook finishes, so I used trylast=True one more time.

Answer 3

As helpfully hinted by massimo, a possible solution is to use a hook, specifically pytest_unconfigure which can be placed in conftest.py so that it is available for all tests.

def pytest_unconfigure(config):
    if platform.system() in ['Darwin', 'Windows']:
        html_report_path = os.path.join(config.invocation_dir.strpath, config.option.htmlpath)
        open_url_in_browser("file://%s" % html_report_path)