provider/ec2: use s3.RetryAttempts

provider/ec2: use s3.RetryAttempts

This speeds the tests up from about 80s to 3s.

I've also taken this opportunity to clean up some
of the test code.

https://code.launchpad.net/~rogpeppe/juju-core/373-ec2-no-s3-retry/+merge/181759

(do not edit description out of merge proposal)

[axw1, 2013-08-23 09:57:10]

LGTM

[jtv.canonical, 2013-08-23 10:07:43]

Great to see this happen, thanks.

https://codereview.appspot.com/12787050/diff/3001/provider/ec2/local_test.go
File provider/ec2/local_test.go (right):

https://codereview.appspot.com/12787050/diff/3001/provider/ec2/local_test.go#...
provider/ec2/local_test.go:339: c.Assert(urls[0], gc.Equals,
imagemetadata.DefaultBaseURL)

Nitpicking here, so feel free to ignore, but I generally prefer c.Check() for
potential future additions — and c.Assert() only for necessary conditions for
continuing with the test.

https://codereview.appspot.com/12787050/diff/3001/provider/ec2/local_test.go#...
provider/ec2/local_test.go:343: // behaves as if it not in the us-east region.

Typo in this comment line.  No biggie.

https://codereview.appspot.com/12787050/diff/3001/provider/ec2/local_test.go#...
provider/ec2/local_test.go:363: t.srv.config = &s3test.Config{

It's particularly nice to see this test-specific setup limited to just the suite
that needs it, instead of being applied all the time.

[jtv.canonical, 2013-08-23 10:08:12]

And "LGTM."  Forgot that bit.

[rog, 2013-08-23 15:28:18]

Please take a look.

https://codereview.appspot.com/12787050/diff/3001/provider/ec2/local_test.go
File provider/ec2/local_test.go (right):

https://codereview.appspot.com/12787050/diff/3001/provider/ec2/local_test.go#...
provider/ec2/local_test.go:339: c.Assert(urls[0], gc.Equals,
imagemetadata.DefaultBaseURL)
On 2013/08/23 10:07:43, jtv.canonical wrote:
> 
> Nitpicking here, so feel free to ignore, but I generally prefer c.Check() for
> potential future additions — and c.Assert() only for necessary conditions for
> continuing with the test.

Agreed. Done.

https://codereview.appspot.com/12787050/diff/3001/provider/ec2/local_test.go#...
provider/ec2/local_test.go:343: // behaves as if it not in the us-east region.
On 2013/08/23 10:07:43, jtv.canonical wrote:
> 
> Typo in this comment line.  No biggie.

Done.

[rog, 2013-08-23 16:24:12]

Please take a look.