Helpers for Testing (pyvo.utils.testing)

This package contains a few helpers to make testing pyVO code that does a lot of network interaction simpler. It is not intended to be used by user code or other libraries at this point; the API might change at any time depending on the testing needs of pyVO itself, and this documentation (mainly) addresses pyVO developers.

The LearnableRequestMocker

By its nature, much of pyVO is about talking to remote services. Talking to these remote services in order to test pyVO code makes test runs dependent on the status of external resources and may be slow. It is therefore desirable to “can” responses to a large extent, i.e., use live responses to define a test fixture usable offline. This is what LearnableRequestMocker tries to support.

To use it, define a fixture for the mocker, somewhat like this:

def _all_constraint_responses(requests_mock):
    matcher = LearnableRequestMocker("image-with-all-constraints")

The first constructor argument is a fixture name that should be unique among all the fixtures in a given subdirectory.

When “training“ your mocker, run pytest --remote-data=any. This will create one or more pairs of files in the cache directory, which is a sibling of the current file called data/<fixture-name>. Each request produces two files:

  • <base-name>.meta: a pickle of the request and selected response metadata. You probably do not want to edit this.

  • <base-name>: the resonse body, which you may very well want to edit.

All these must become part of the package for later tests to run without network interaction. The <base-name> is intended to facilitate figuring out which response belongs to which request; it consists of the method, the host, and hashes of the full URL and a payload.

When the upstream response (or whatever request pyvo produces) changes, remove the cached files and re-run test with --remote-data=any.

We do not yet have a good plan for how to preserve edits made to the test files. For now, commit the original responses, do any changes, and do a commit encompassing only these changes.


pyvo.utils.testing Module

Shared utilities for unit (and not-so-unit) tests.

TODO: perhaps move the contents of pyvo.registry.tests.conftest here, too?



returns a hash-type string for data.


returns a hash for a data/params argument in request.


LearnableRequestMocker(fixture_name, *[, ...])

Create a new mocker adapter.

Class Inheritance Diagram

Inheritance diagram of pyvo.utils.testing.LearnableRequestMocker