Repository tests are broken in master branch

[phamann]

Whilst trying to submit a new pull request to improve the loading functionality I was unable to get the tests to run from a clean checkout of the repo in master.

Running npm test generates the following error:

TypeError: setTimeout(...).unref is not a function

Steps to reproduce:

• git clone git@github.com:SinaMFE/assemblyscript-typescript-loader.git
• cd assemblyscript-typescript-loader
• npm install
• npm test

Environment:

• MacOS 10.14.4
• NPM 6.9.0
• Node v10.15.0