Using VCR and pytest with pytest-recording

pytest-recording is a neat pytest plugin that makes it easy to use the VCR library, which helps write tests against HTTP resources by automatically capturing responses and baking them into a YAML file to be replayed during the tests.

It even works with boto3!

To use it, first install it with pip install pytest-recording and then add the @pytest.mark.vcr decorator to a test that makes HTTP calls:

def test_create():
    runner = CliRunner()
    with runner.isolated_filesystem():
        result = runner.invoke(cli, ["create", "pytest-bucket-simonw-1", "-c"])
        assert result.exit_code == 0

The first time you run the tests, use the --record-mode=once option:

pytest -k test_create --record-mode=once

This defaults to creating a YAML file in tests/cassettes/test_s3_credentials/test_create.yaml.

Subsequent runs of pytest -k test_create will reuse those recorded HTTP requests and will not make any network requests - I confirmed this by turning off my laptop's WiFi.

Created 2021-11-02T17:51:51-07:00 · Edit