Use new tmp/output location for Testem.

[rwjblue]

This allows using the command line version of testem in addition to running
in CI mode (the current behavior).

[twokul]

LGTM, @abuiles can you +1/-1?

[rwjblue]

There is an issue with auto-reloading when using the command line version of Testem (via testem). I'm working on it now....

[abuiles]

👍

[abuiles]

@rjackson thanks! let me know if you need any help with the auto-reloading issue.

[rwjblue]

It does not appear that testem itself is restarting tests properly when files change. I created a super simple static file test repo at https://github.com/rjackson/testem-reload-failure which demonstrates the problem fairly well. I have also commented on an open issue in the Testem repo here: testem/testem#314 (comment)

So the issue is not with my changes here (they at least allow testem to work properly from the command line), and I think this is mergeable as is. I will continue to work with the Testem folks to try and track down why this fails.

[stefanpenner]

can you add a changelog entry?

[rwjblue]

@stefanpenner - CHANGELOG.md entry added.

[rwjblue]

Next step is to make ember test --server work properly. I believe once I add that we will be able to get the reloads/restarts properly from Testem, as we will just trigger their programmatic API directly.

Working on PR now.

[stefanpenner]

test:server

[stefanpenner]

or we can do --server

[rwjblue]

I'm just cleaning up a few failing tests, but i have test --server working now. Happy to change either way...

[stefanpenner]

👍