Implement a test suite and Travis CI

[whphhg]

Research and implement the currently best approach for React and MobX testing. Then add
continuous integration using Travis CI.

• Test suite
• TravisCI (thanks to @sum01)

[JohnVonNeumann]

Haven't really participated in this type of stuff before, but what are you estimating timespan wise for this? I'm happy to help out with the research and whatnot. Happy to get some pointers.

[whphhg]

Hej, thanks for the interest in helping!

I'd say roughly a week to get everything tested and go through a couple of cleanups to reach the cleanest version possible, no bloat (provided you're familiar with the source). I'd begin by testing the components first, then move to more complex stores like wallet/send.

A good place to start researching would be https://mobx.js.org/faq/blogs.html. As I copied the URL I saw How to Test React and MobX with Jest in the tutorials section. That's where I'd start, see if it's still the best approach or if there's something else being used now and go from there.