Remove race condition in resource test.

[robdimsdale]

Fixes #12

I know the race condition was only in test code, but it was still cluttering up the test output.

We could do something more intelligent with channels/mutex if the data really did need to be read across multiple go routines, but I think in this case it's not necessary. I accept it's slightly annoying to not have the exit code declared or defined alongside other related variables anymore.

Open to suggestions as to other ways to fix this.

[vito]

I think this is actually from the tests not properly waiting for the example's process to exit afterwards. I'll do a commit to fix it that way. Thanks for pointing this out; I thought we were running with -race in CI this whole time, but I guess not. Fixing that too.