Add Unit test for tensorspace

[syt123450]

Write unit test for utils, add test script under test/unit folder.

[BoTime]

Headless Chromium for continuous integration testing

https://medium.com/@metalex9/replace-phantomjs-with-headless-chromium-for-javascript-unit-testing-in-karma-59812e6f8ce4

[BoTime]

Sample repo for using karma + headless chromium + jasmine in TravisCI

https://github.com/BoTime/travisci-test

[syt123450]

I Added a basic test case here in testcase branch. @BoTime

[BoTime]

https://github.com/BoTime/travisci-test
https://github.com/BoTime/travisci-test/blob/master/test/e2e.spec.js

A working example to test Tensorspace based on your example. But your example is more like an integration test or e2e test.

To run it

# set environment to Travis
export CI=true

npm install
npm test

# reset to environment to local
unset CI

@syt123450

[BoTime]

https://blog.kentcdodds.com/write-tests-not-too-many-mostly-integration-5e8c7fff591c
@syt123450