Expand travis support

[Thomasdezeeuw]

Start testing on OS X.
Print the version of cargo and rustc at the start of the testing,
useful for testing with nightly.
Add cargo to the cache.
Enable the verbose flag while building and testing.

[Thomasdezeeuw]

It seems that pip isn't install on Travi's OS X box by defualt. I'll see if I can get it to install somehow.

[Thomasdezeeuw]

Well I'm not sure how to get pip on OS X on Travis. On my local machine brew says pip gets installed if you install python, but on Travis it doesn't, or at least the command still isn't found.

[Thomasdezeeuw]

The python issue is finally fixed. This should be good to go.

[carllerche]

Hi, thanks for the PR. I specifically removed the OS X platform from CI because:

1. The behavior should be tested by mio
2. OS X testing with travis is really slow.

Is there a reason you think it should be added back?

[Thomasdezeeuw]

On both points you're correct. OS X is slow on Travis, but does it really matter? For most pull requests this delay doesn't matter much does it? Most of them live as a pr for a while, while being reviewed etc, before being accepted anyway. There are some small prs that would be block, but even then I believe the benefit would outweight this waiting time.

For the first point; Tokio itself is still more then 1k lines of code on top of mio. I would like to see that to be tested on Mac OS as well. I would even recommed to use AppVeyor to test on Windows. This way bugs are caught a testing platform, while the changes are made. Rather after a change is accepted, basically the same arguments as to having testing at all.

[alexcrichton]

Mind switching to a template like this? I agree it's good to run OSX as we've discovered bugs before in tokio-core (in mio) on OSX. We don't need to run 3 builders of OSX though (stable/beta/nightly) but instead we can just run one builder of OSX and in general not worry too much if it takes awhile.

[carllerche]

IMO we can hold off on this until the bulk of the work is done. It isn't super critical this second and it will just slow down iteration.

We can add OS X back to the CI run once things stabilize a bit.

[Thomasdezeeuw]

I'll close the PR as per @carllerche comment and it can be done later.