backend-explicit tests

[mattsb42-aws]

The current test framework loads all cryptographic backends and then tests them all in the same pass.

This has a few unintended effects: it makes it impossible to run the tests without all backends present, it masks failures of some tests that will fail when certain backends are not present (because they use the autoloader), and it makes it easier to forget to enable tests for certain backends.

I've been hacking on this and I have the tests reconfigured to enable testing with isolated backends[1], but as noted above the previous approach was masking tests that currently fail when certain backends are not present.

Assuming that this is a change that would be desirable, what would be your preferred way of handling the changes? In the interest of keeping the PRs small and digestible I would rather not lump the test reworking and any fixes together into the same PR, but pushing only the test rework will make the test suite fail.

[1] https://github.com/mattsb42-aws/python-jose/tree/explicit-dependencies

[mpdavis]

@mattsb42-aws This is great work. I have had this in the back of my mind for some time.

If it works for you, I could set up a dev branch that we could PR everything into for digestable PRs. Once everything was into the dev bracnh, we could merge that into master.

I created a branch https://github.com/mpdavis/python-jose/tree/backend-explicit-tests

You can PR individual PRs into that branch.

Thanks again.

[mattsb42-aws]

Sounds good. #109 created for the initial move.

Related to this, I would like to remove the pyca/cryptography backend's dependency on the ecdsa library. From what I remember looking through it, the only gaps in functionality were a couple small utility functions that it might be better (from my perspective) to simply absorb. The reason for this is that it would allow use of this library without requiring the ecdsa library, which is desirable for us in working to reduce usage of certain libraries.

Once that gap is closed, I would like to see what can be done to remove the dependencies for both ecdsa and rsa when using the pyca/cryptography backend, as neither will be necessary at that point. I toyed with this a couple weeks ago, but couldn't figure out how to have setuptools only install certain dependencies if no extras value is set. This might require a custom setuptools command.

[zejn]

I was looking for that too when implementing different backends. It appears setuptools still can't deal reliably with this according to pypa/setuptools#1139

[mattsb42-aws]

This is resolved with #129