* update test-helpers to 0.5.6-rc.0

* remove comment that no longer applies

* fix uses of expectEvent.notEmitted

* remove mocha only

* update to final version

* Update test/token/ERC777/ERC777.test.js

Co-authored-by: Nicolás Venturo <nicolas.venturo@gmail.com>

Co-authored-by: Nicolás Venturo <nicolas.venturo@gmail.com>