Class setup/teardown workflow

Handling cassettes recording and deletion on failure inside class scoped setup / teardown is an often needed feature but not immediate to implement (internally pytest treats function scoped and class scoped failures slightly differently).

These are two viable different implementations, base respectively on pytest.mark.vcr_delete_on_fail() and on vcr_and_dof().

vcr_delete_on_fail

import pytest
import requests
import vcr
from typing import Union
from pytest_vcr_delete_on_fail import has_class_scoped_setup_failed
from contextlib import contextmanager
from pathlib import Path


def get_setup_cassette_path(node) -> str:
    # determine the class setup cassette path from the node
    name = f"{node.cls.__name__}.__setup__.yaml"
    return str(Path(node.path.parent / "cassettes" / node.path.stem / name))


@pytest.fixture(scope="class")
def vcr_setup(request):
    # This fixture returns a context manager that records network
    # requests to a class setup cassette
    cassette_path = get_setup_cassette_path(request.node)
    setup_vcr = vcr.VCR(record_mode=["once"])

    @contextmanager
    def _wrapped(**kwargs):
        with setup_vcr.use_cassette(cassette_path, **kwargs) as v:
            yield v

    return _wrapped


def get_class_setup_cassette_if_failed(item) -> Union[str, None]:
    # check if the class has been flagged with a failed class setup, after the test has run
    if has_class_scoped_setup_failed(item):
        # return the class setup cassette path; this could, if needed, return a list of
        # all class cassettes
        return get_setup_cassette_path(item)
    # otherwise return None


# This marker is responsible for the deletion of the setup cassette on fail
delete_setup_on_fail = pytest.mark.vcr_delete_on_fail(
    [get_class_setup_cassette_if_failed]
)


@delete_setup_on_fail
class TestATestCollection:

    @pytest.fixture(scope="class", autouse=True)
    def setup(self, request, vcr_setup):
        with vcr_setup():
            # Everything in here will be recorded on the setup cassette
            request.cls.value = requests.get("{test_url}")
            raise Exception
        # Do note that this yield should be outside the vcr_setup block, otherwise
        # every network request performed by this class' tests will be recorded
        # in the setup cassette
        yield

    def test_failing_at_class_setup(self):
        # This won't even run, since it will fail at setup time
        assert self.value.status_code == 200

Between the two, this is the more verbose solution. It has the advantage that it can detect a failure in a setup setup fixture, since it uses pytest.mark.vcr_delete_on_fail().

Note

The full signature of has_class_scoped_setup_failed() and has_class_scoped_teardown_failed() can be found in the API Reference.

vcr_and_dof

import pytest
import requests
import vcr
from pytest_vcr_delete_on_fail import vcr_and_dof
from contextlib import contextmanager
from pathlib import Path

my_vcr = vcr.VCR(record_mode="once")

# The following fixture returns a context manager that records network request to a class
# setup cassette. It will also delete said cassette if an exception is raised
@pytest.fixture(scope="class")
def vcr_and_dof_setup(request):
    name = f"{{request.node.cls.__name__}}.__setup__.yaml"
    cassette_path = str(
        Path(request.node.path.parent / "cassettes" / request.path.stem / name)
    )

    @contextmanager
    def _wrapped(**kwargs):
        with vcr_and_dof(my_vcr, cassette_path, **kwargs) as v:
            yield v

    return _wrapped


class TestATestCollection:

    code: int

    @pytest.fixture(scope="class", autouse=True)
    def setup(self, request, vcr_and_dof_setup):
        with vcr_and_dof_setup(
            # if needed, all class cassettes can be deleted on fail by adding them here
            additional_cassettes=[],
        ):
            # Everything in here will be recorded on the setup cassette
            # Any exception will immediately delete the cassette
            request.cls.code = requests.get("{test_url}").status_code
            raise Exception
        # Do note that this yield should be outside the vcr_and_dof_setup block, otherwise every
        # network request performed by this class tests will be recorded in the setup cassette.
        # Also, every exception will trigger the setup cassette deletion
        yield

    def test_failing_at_class_setup(self):
        # This won't even run, since it will fail at setup time
        assert self.code == 200

While being more concise and simple, this solution only detect failures inside the vcr_and_dof_setup context manager.