Replace yield from with await...

[terricain]

#281 Point 2 Replace yield from with await.

Well this resulted in a nastier diff than I expected :D.

Have replaced the majority of the yield from with await and @asyncio.coroutine with async

This is more a placeholder for when you want to purge the yield from. Its not 100% finished but if you fancy reading through it, by all means :)

[terricain]

Yeah this stopped working... not too sure why

[codecov]

Codecov Report

Merging #283 into master will decrease coverage by 0.8%.
The diff coverage is 95.43%.

@@            Coverage Diff             @@
##           master     #283      +/-   ##
==========================================
- Coverage   92.93%   92.12%   -0.81%     
==========================================
  Files           9        9              
  Lines        1161     1118      -43     
  Branches      173      158      -15     
==========================================
- Hits         1079     1030      -49     
- Misses         53       61       +8     
+ Partials       29       27       -2

Impacted Files	Coverage Δ
aiomysql/sa/result.py	90.86% <100%> (-0.4%)	⬇️
aiomysql/sa/engine.py	88.5% <100%> (-11.5%)	⬇️
aiomysql/pool.py	94.93% <89.65%> (-1.32%)	⬇️
aiomysql/sa/connection.py	92.07% <92.72%> (-0.24%)	⬇️
aiomysql/utils.py	84.76% <96%> (+2.94%)	⬆️
aiomysql/cursors.py	93.9% <96.49%> (-0.11%)	⬇️
aiomysql/sa/transaction.py	95.83% <96.66%> (-0.17%)	⬇️

---

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[jettify]

Can you please split this PR in 2 parts: just port tests, without library change and subsequent PR with library change? Should be easy to do, since you have one commit per file. I can help you with splitting.

Reason for 2 PR, I just want to be extra caution that move to async def does not introduce new issue.

[jettify]

Other question, is what minimum version of python3.5 we should support?

[terricain]

Sure makes much more sense. Any recommendations for splitting the PR, as normally I resort to mashing git commands until it looks ok 😄.

As for Python3.5 versions, I don't know enough about the differences between patch versions, do you know of anything that we should be cautious of? Otherwise, 3.5.2 is on Ubuntu, so assuming that has a fair market share, that's not a bad minimum.

[jettify]

I was thinking about 3.5.3, since older versions has annoying bug with with asyncio.get_event_loop(), it may return other loop not currently running in some strange cases.

[terricain]

LOL yeah that is an annoying bug. Sure 3.5.3 is fine by me, im on 3.6 :D

[jettify]

cherry picked tests locally to make sure all set

[jettify]

thanks!