WIP: add test suite for es2015 polyfills

[jamestalmage]

Based on the conversation in #263, I'm starting to work up a test suite that
actually excercises ALL the ES2015 features, so we know what we are missing.

This is a rough start. If someone wants to help divide and conquer, just ping me on
Gitter to discuss.

[vadimdemedes]

Oooh, I am not sure about this one. Our test suite will grow tremendously, if we test every ES6 feature. That's definitely up to babel project to test these. We just need to fix our babel issues and get it right.

[sindresorhus]

Good idea! But I think this would be better as a separate project. Something like a ES2015 tester project that both we and Babel could consume.

[sindresorhus]

There's actually https://github.com/kangax/compat-table which already does this. Should probably just reuse that one instead.

[vadimdemedes]

@sindresorhus +1

[jamiebuilds]

@sindresorhus https://github.com/kangax/compat-table is a bad test suite for ES6 features, it's very shallow. https://github.com/tc39/test262 is better

[sindresorhus]

I think we should put this on hold until we have upgraded to Babel 6.

[sindresorhus]

But I think this would be better as a separate project. Something like a ES2015 tester project that both we and Babel could consume.

Closing for the above reason. @jamestalmage If you're no longer interested in doing this and think it's still relevant, can you open an issue?