add graphql websocket subsciption tests

[dwsutherland]

Adds an integration test for testing the graphql subscriptions via websocket connection.

Check List

• I have read CONTRIBUTING.md and added my name as a Code Contributor.
• Contains logically grouped changes (else tidy your branch by rebase).
• Does not contain off-topic changes (use other PRs for other changes).
• Applied any dependency changes to both setup.cfg (and conda-environment.yml if present).
• Tests are included (or explain why tests are not needed).
• Changelog entry included if this is a change that can affect users
• Cylc-Doc pull request opened if required at cylc/cylc-doc/pull/XXXX.
• If this is a bug fix, PR should be raised against the relevant ?.?.x branch.

[oliver-sanders]

LGTM, one question (see comment).

This pushes code coverage in the right direction 👍:

There are still a few gaps:

• Would be good to cover error handling, e.g, GraphQL validation errors.
• Would be good to cover more of the websocket subprocotocol (though note that we will change subprotocol soon)
• Would be good to cover connection termination (as this is something we've had issues with).

[dwsutherland]

There are still a few gaps:

Yes, this is a work in process, I'll keep expanding the tests here (hopefully until 85% project coverage at min)

[oliver-sanders]

83% project coverage 🥇

Ping me when you want a review.

[dwsutherland]

83% project coverage 🥇

Ping me when you want a review.

Just need to bump up the websocket/subscription side of things first.

[dwsutherland]

@oliver-sanders - I think this will do for now, there's some more that could be done with the subscription handler.. But we might as well get this in as a first step for people to build on.

[oliver-sanders]

(shifting this onto the 1.9.0 milestone as there are functional code changes)

[oliver-sanders]

(shifting this onto the 1.9.0 milestone as there are functional code changes)

FYI: We'll be looking to release 1.9.0 shortly once the new Cylc Review is in, would be great to merge this pre-release.

[dwsutherland]

(re-running CI on fresh merge to see if coverage reports change)

Looks like it's showing as covered now.. I don't want to be too finicky about tornado_ws.py with #821
in bound..

So good to go as is, then I can build on it.. i.e. with #597

[oliver-sanders]

(Codecov sometimes jitters, I think test re-runs can cause it, a fresh run fixes it)

[MetRonnie]

Sorry David, I've spotted that #823 didn't actually enable flake8 for the tests, please standby, pending #842

[MetRonnie]

Kicking tests

[oliver-sanders]

@dwsutherland, have pushed some lint fixes to this branch in order to nudge this forward.