fix: ensure promise tests are correct

[dignifiedquire]

This fixes the test failures in ipfs/js-ipfs#392

@diasdavid please review

[daviddias]

wanna bump it to 5?

[dignifiedquire]

:D sure

[daviddias]

Could you give more info of what was the failure?

[daviddias]

Have you tested it against js-ipfs-api?

[dignifiedquire]

This is the failure: (build: https://circleci.com/gh/ipfs/js-ipfs/665)

1. core --both .files promise API .add buffer:
   Error: Resolution method is overspecified. Specify a callback or return a Promise; not both.
   at webpack:///~/interface-ipfs-core/lib/files.js:226:0 <- test/browser.js:162249:13

2. core --both .files promise API .add buffer:
   Resolution method is overspecified. Specify a callback or return a Promise; not both.

[daviddias]

I'm surprised that this error just happened now. Can you tell what got broken meanwhile?

Otherwise LGTM

[dignifiedquire]

The error is part of mocha@3 which checks for this explicitly, before it just go silently swallowed. The confusing part is that I actually didn't yet upgrade that branch to mocha 3, but it needs fixing in any case.

[dignifiedquire]

Have you tested it against js-ipfs-api?

just tested and things pass

[daviddias]

mocha@3

Thank you for clarifying :)