[close #50] Annotate rspec errors

[schneems]

For intermittent failures it's important to get as much debugging information as possible about the test in progress. This PR annotates any rspec expectation failures that happen in a deploy {} block with the application name. Here's an example of what it will look like:

     Failure/Error: expect(true).to eq(false)

       App: hatchet-t-873bcea87c (default_ruby)

       expected: false
            got: true

       (compared using ==)

       Diff:
       @@ -1 +1 @@
       -false
       +true

In this example if the failure was due to an app.run then we could manually app.run against the same app (assuming it had not been reaped yet) in order to better debug.

[Malax]

Would it be possible to also get the example description (the sentence created with describe, context, and it)? Otherwise, this looks good and will greatly improve the debugging experience! 👍

[schneems]

Would it be possible to also get the example description (the sentence created with describe, context, and it)? Otherwise, this looks good and will greatly improve the debugging experience! 👍

Since this is me adding additional info to rspec, yes that info will be there, but only for failing tests. For tests that are retried, the output will still be the same as today. I could maybe change that, but I would have to work upstream in the rspec-retry repo which I've not done before.