Setup e2e testing with BDD, Cypress & Cucumber

[mst101]

With reference to #81 here's my attempt at setting up some e2e testing...

[MrWook]

I love it and i will comment here to #81 (comment)

I think i like the table. This way we have a place where we have a common understanding of what should be the case, this could be moved into the vue-press documentation.
It took me a while to really understand it :D but at the end it kinda looks like a table for a state machine.

I never really got into cypress so this is new for me to but it looks quite nice and usefull.

The show-calendar-on-focus looks either like a timing thing or something with the store in firefox because if you create a test with the property set to true from the beginning it works.
I didn't test the second bug but i would guess this is the same problem as the first one if not, you just fixed a bug.

Like always thank you for your contribution 👍

[mst101]

@MrWook These latest commits contain the end-to-end tests that describe the desired keyboard navigation functionality (which is based on the Google Chrome functionality you referenced at https://developer.mozilla.org/en-US/docs/Web/HTML/Element/input/date).

I guess the main thing to check over here is the FEATURES.md file which is now more complete, albeit more complicated, than the original version. As you can see, in addition to describing the state before and after a user action takes place, it maps that behaviour to a specific test id. These tests are defined (in Gherkin) in the /test/e2e/specs/*.feature files and are implemented (via Cypress) in the corresponding folders' index.js files.

I'm currently writing up the code changes to satisfy these tests and will send that through in a separate PR. In the meantime, if you want to see what these changes look like in practice you can check the latest version of the feat/navigate-via-keyboard branch at #81.