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https://github.com/getsentry/pytest-sentry

Track flaky tests in Sentry
https://github.com/getsentry/pytest-sentry

flaky-tests pytest pytest-plugin sentry tag-non-production

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Track flaky tests in Sentry

Lists

README 

        
=============

pytest-sentry

=============



.. image:: https://img.shields.io/pypi/v/pytest-sentry

    :target: https://pypi.org/project/pytest-sentry/



.. image:: https://img.shields.io/pypi/l/pytest-sentry

    :target: https://pypi.org/project/pytest-sentry/



``pytest-sentry`` is a `pytest `_ plugin that uses `Sentry

`_ to store and aggregate information about your testruns.



**This is not an official Sentry product.**



Tracking flaky tests as errors

==============================



Let's say you have a testsuite with some flaky tests that randomly break your

CI build due to network issues, race conditions or other stuff that you don't

want to fix immediately. The known workaround is to retry those tests

automatically, for example using `pytest-rerunfailures

`_.



One concern against plugins like this is that they just hide the bugs in your

testsuite or even other code. After all your CI build is green and your code

probably works most of the time.



``pytest-sentry`` tries to make that choice a bit easier by tracking flaky test

failures in a place separate from your build status. Sentry is already a

good choice for keeping tabs on all kinds of errors, important or not, in

production, so let's try to use it in testsuites too.



The prerequisite is that you already make use of ``pytest`` and

``pytest-rerunfailures`` in CI. Now install ``pytest-sentry`` and set the

``PYTEST_SENTRY_DSN`` environment variable to the DSN of a new Sentry project.



Now every test failure that is "fixed" by retrying the test is reported to

Sentry, but still does not break CI. Tests that consistently fail will not be

reported.



Tracking the performance of your testsuite

==========================================



By default ``pytest-sentry`` will send `Performance

`_ data to Sentry:



* Fixture setup is reported as "transaction" to Sentry, such that you can

  answer questions like "what is my slowest test fixture" and "what is my most

  used test fixture".



* Calls to the test function itself are reported as separate transaction such

  that you can find large, slow tests as well.



* Fixture setup related to a particular test item will be in the same trace,

  i.e. will have same trace ID. There is no common parent transaction though.

  It is purposefully dropped to spare quota as it does not contain interesting

  information::



      pytest.runtest.protocol  [one time, not sent]

        pytest.fixture.setup [multiple times, sent]

        pytest.runtest.call [one time, sent]



  The trace is per-test-item. For correlating transactions across an entire

  test run, use the automatically attached CI tags or attach some tag on your

  own.



To measure performance data, install ``pytest-sentry`` and set

``PYTEST_SENTRY_DSN``, like with errors. By default, the extension will send all

performance data to Sentry. If you want to limit the amount of data sent, you

can set the ``PYTEST_SENTRY_TRACES_SAMPLE_RATE`` environment variable to a float

between ``0`` and ``1``. This will cause only a random sample of transactions to

be sent to Sentry.



Transactions can have noticeable runtime overhead over just reporting errors.

To disable, use a marker::



    import pytest

    import pytest_sentry



    pytestmarker = pytest.mark.sentry_client({"traces_sample_rate": 0.0})



Advanced Options

================



``pytest-sentry`` supports marking your tests to use a different DSN, client or

scope per-test. You can use this to provide custom options to the ``Client``

object from the `Sentry SDK for Python

`_::



    import random

    import pytest



    from sentry_sdk import Scope

    from pytest_sentry import Client



    @pytest.mark.sentry_client(None)

    def test_no_sentry():

        # Even though flaky, this test never gets reported to sentry

        assert random.random() > 0.5



    @pytest.mark.sentry_client("MY NEW DSN")

    def test_custom_dsn():

        # Use a different DSN to report errors for this one

        assert random.random() > 0.5



    # Other invocations:



    @pytest.mark.sentry_client(Client("CUSTOM DSN"))

    @pytest.mark.sentry_client(lambda: Client("CUSTOM DSN"))

    @pytest.mark.sentry_client(Scope(Client("CUSTOM DSN")))

    @pytest.mark.sentry_client({"dsn": ..., "debug": True})



The ``Client`` class exposed by ``pytest-sentry`` only has different default

integrations. It disables some of the error-capturing integrations to avoid

sending random expected errors into your project.



Accessing the used Sentry client

================================



You will notice that the global functions such as

``sentry_sdk.capture_message`` will not actually send events into the same DSN

you configured this plugin with. That's because ``pytest-sentry`` goes to

extreme lenghts to keep its own SDK setup separate from the SDK setup of the

tested code.



``pytest-sentry`` exposes the ``sentry_test_scope`` fixture whose return value is

the ``Scope`` being used to send events to Sentry. Use ``with use_scope(entry_test_scope):``

to temporarily switch context. You can use this to set custom tags like so::



    def test_foo(sentry_test_scope):

        with use_scope(sentry_test_scope):

            sentry_sdk.set_tag("pull_request", os.environ['EXAMPLE_CI_PULL_REQUEST'])



Why all the hassle with the context manager? Just imagine if your tested

application would start to log some (expected) errors on its own. You would

immediately exceed your quota!



Always reporting test failures

==============================



You can always report all test failures to Sentry by setting the environment

variable ``PYTEST_SENTRY_ALWAYS_REPORT=1``.



This can be enabled for builds on the ``main`` or release branch, to catch

certain kinds of tests that are flaky across builds, but consistently fail or

pass within one testrun.



License

=======



Licensed under 2-clause BSD, see ``LICENSE``.