coverage: low-hanging fruit

[oliver-sanders]

There are a bunch of small coverage holes in our tests, some of which should be fairly easy to fix.

Have a skim through these:

• https://app.codecov.io/gh/cylc/cylc-flow/blob/master/cylc%2Fflow%2Fexceptions.py
• https://app.codecov.io/gh/cylc/cylc-flow/blob/master/cylc%2Fflow%2Ftask_outputs.py
• https://app.codecov.io/gh/cylc/cylc-flow/blob/master/cylc%2Fflow%2Ftime_parser.py
• https://app.codecov.io/gh/cylc/cylc-flow/blob/master/cylc%2Fflow%2Ftask_proxy.py (get_point_as_seconds only)
• https://app.codecov.io/gh/cylc/cylc-flow/blob/master/cylc%2Fflow%2Ftask_id.py

And try to write Pytests which fill the coverage holes.

These holes may indicate options that we are not using, if this is the case and it's a hassle to fill the hole, check the option isn't used in cylc-rose or cylc-uiserver then flag it here and we'll consider removal.

[samuel-denton]

In cylc/flow/exceptions.py lines 103 to 108, we are missing some code coverage of the CylcError class TaskProxySequenceBoundsError. I wrote a test for this, however, on further investigation, this error is never raised. It is imported and caught in cylc/flow/scripts/validate.py line 185, but that except TaskProxySequenceBoundsError: can never trigger as far as I can tell.

It looks like the one instance of it being raised was removed in this commit: edf61d3
Used to be on line 199 of cylc/flow/task_proxy.py

So I can either add my test and a comment to this effect, or remove the dead code (probably in a different PR?).

Up to you @oliver-sanders, it's possible the error is there to be used again in future?

[oliver-sanders]

Good detective work.

Coverage holes often indicate unused code which can be safely removed, it looks like this is an example. So, in this case rather than filling this coverage hole, please remove the unreachable code branch.

FYI: It's worth checking other Cylc/Rose projects as code is sometimes unused in one repo, but relied on in another. I've done a quick git grep TaskProxySequenceBoundsError in the metomi-rose, cylc-rose and cylc-uiserver repos and can find no uses.

[samuel-denton]

https://app.codecov.io/gh/cylc/cylc-flow/blob/master/cylc%2Fflow%2Fexceptions.py

Should be 100% coverage once the unreachable code is removed. Currently at 99.39% up from 94.55%

[samuel-denton]

Opened #7295 to deal with unreachable code.

[samuel-denton]

https://app.codecov.io/gh/cylc/cylc-flow/blob/master/cylc%2Fflow%2Ftask_outputs.py

Up to 100% from 96.32%

[samuel-denton]

https://app.codecov.io/gh/cylc/cylc-flow/blob/master/cylc%2Fflow%2Ftime_parser.py

Up to 100% from 91.83%.

[samuel-denton]

https://app.codecov.io/gh/cylc/cylc-flow/blob/master/cylc%2Fflow%2Ftask_proxy.py (get_point_as_seconds only)

Coverage is 100% up from 96.26%.

[samuel-denton]

As discussed, I will go through
https://app.codecov.io/gh/cylc/cylc-flow/blob/master/cylc%2Fflow%2Ftask_id.py with @Scott-Owen-James on Monday as an introduction to codecov.