Implement e2e testing

[IanMayo]

We should produce some "demonstration" e2e tests. Then we can follow that model as the app grows.

The developer for this issue should do some research on e2e frameworks, then look at our app and give a list of the types of things to be covered by e2e testing.

Once that's all agreed the developer can start implementing the tests.

Thoughts for E2E testing

• App loads, force load of reference UI, verify categories/entries defined
• Click on particular button, check modal dialog opens
• Cancel modal dialog, check narrative listing still empty
• Trigger event again, enter insufficient data, Accept disabled
• Provide sufficient data, Accept enabled, press Accept. Verify new entry in Narrative

[Morphexe]

This is basically what I have been doing on the unit tests.
There is even a testing feature where you take a snapshot of the component, and the test is "does the component look the same?" if it changes, it won't pass. (you can create new snaps when you want)

You can also simulate clicks, keypress, etc, with Jest and Enzyme which I think would cover most if not all the situations.

The current implemented tests are pretty simple, but I could work on doing more robust unit tests, and design some 2e2 tests if its required.

[IanMayo]

Thanks for the advice. Let's defer this.