Add timeout options

[fjetter]

This adds the option to add timeouts to tests either via marker kwargs or via options/CLI arguments.

The naming of the options is intentionally prefixes with asyncio to avoid clashes with pytest-timeout. Marker kwargs do not have this ambiguity and I therefore allowed both.

I don't have a good sense on how to test the options via config and CLI. If somebody got an idea, I'd be happy to implement it.

Closes #215
Depends on pytest-dev/pytest-timeout#117

[asvetlov]

Please read https://docs.pytest.org/en/6.2.x/writing_plugins.html#testing-plugins

pytester fixture can be used for testing command-line and ini files.

The plugin has no documentation, IMHO.
I can suggest only the source code and example of usage in aiohttp.

Here is an example of calling pytest with custom cmdline arguments: https://github.com/aio-libs/aiohttp/blob/master/tests/test_pytest_plugin.py#L140-L150

[codecov-commenter]

Codecov Report

Merging #216 (1009cc0) into master (4c7da65) will increase coverage by 0.36%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##           master     #216      +/-   ##
==========================================
+ Coverage   95.43%   95.79%   +0.36%     
==========================================
  Files           2        2              
  Lines         219      238      +19     
==========================================
+ Hits          209      228      +19     
  Misses         10       10              

Impacted Files	Coverage Δ
pytest_asyncio/plugin.py	95.74% <100.00%> (+0.37%)	⬆️

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[fjetter]

Didn't know about pytester. Thanks for adding the commits!

[asvetlov]

The PR is not complete until timeout disabling on debugging is implemented, as in pytest-timeout.
Otherwise, any tests debug session ends with TimeoutError quickly.
I'm not sure is it worth to copy-paste the whole implementation from pytest-timeout plugin?
Maybe adding timeout_setup()/timeout_teardown() hooks for implementing them in pytest-asyncio makes the code easier and stablier?
Should take time for experimenting.

[altendky]

I'm interested in timeouts for my asyncio tests and it looks like this might be the path to that. Is that correct? What is needed here?

[johnthagen]

Any chance that this PR could make progress? This seems like a really important fundamental tool for testing async functions.

[seifertm]

This PR introduces a "runner" abstraction and adds the timeout functionality. This is also the general way forward for pytest-asyncio. Preferably, these two things should happen in separate PRs, one that introduces the Runner and another one that adds timeout functionality.

PR #312 is draft that does both. Moreover, it adds a dependency on aioloop-proxy which is completely separate from this feature. Since it's unclear who will be able to maintain aioloop-proxy, please try to keep the loop proxy topic separate from #312 if you decide to rebase the draft.

Does that answer your questions?

[fjetter]

I will actually go ahead and close this PR. The code here drifted significantly from my much simpler initial contribution attempt and I do not intend to pick this up again. If somebody wants to finish this up, please open a new PR.