Add more unit tests about carbon-charts

[t-mullen]

Spent some time assessing our test effort today.

Adding code coverage would be a good place to start with this. I wasn't able to get it working with istanbul-coverage, karma-coverage, nyc+instabul-instrument-loader or karma-typescript's coverage though. Those modules really dislike the inclusion of non-code files like SVG. Maybe someone more adept with webpack could take a look.

There are several commented-out unit tests already. They fail with a cryptic "Script Error" that I wasn't able to debug (it has no trace at all).

The existing tests are fragile and fail intermittently. They're all wrapped in timeouts, which could be part of the problem (is this normal for Jasmine tests?).

[theiliad]

We will potentially replace webpack with Rollup. What are the possibilities there?

The tests that use setTimeouts are testing functionality that the library needs to run and update DOM.

[t-mullen]

I'm not sure about Rollup. I noticed some incompatibilities with how webpack does module loading (nyc for example relies on your module loader overriding "require"), so it might help.

Apparently ES6+TypeScript+Karma+Webpack is just not a usecase that any of the code coverage tools account for.

I did manage to get instrumentation working with istanbul-instrument-loader, but none of the coverage tools I tried would report correctly.

[theiliad]

UPDATE

@t-mullen & I are putting together a full test plan (WIP currently), and will start with unit-tests, but will also implement code-coverage analysis down the road:
https://github.com/IBM/carbon-charts/wiki/Test-Plan-for-v1.0