[Delivers #98157690] add client-side form validation

[afeld]

Depends/builds on #656. The diff:

96851664-simplify-forms...98157690-client-side-validation

Changes

• Enables automatic HTML5 form validation via Simple Form
• Includes a refactoring of the client-side form filtering code
• disables the form fields that are hidden by the filter, so that they:
  • Don't get submitted with the form, e.g. sending the recurring_interval value when recurring isn't checked
  • Don't trigger client-side validation warnings
• Set up JS testing using Konacha
• Add tests around the filtering

Yay for limited-internet time to work on this! 🚂

Testing notes

• Ensure that client-side validation works (or at least doesn't break the form) for the normal fields (ideally, in multiple browsers)
• Ensure that empty required hidden fields (e.g. the BA80 fields when BA61 is selected) don't block submissions of the form
• Ensure that values from hidden fields aren't getting sent to the server
• Ensure that Selectize-d fields (the ones with the fancy dropdowns) aren't broken

[jessieay]

Will review after #656 is finished/merged since it seems like there is a good amount of overlap

[afeld]

Ready for some 👀 !

[jessieay]

niiiice

[afeld]

Updated!

[pkarman]

I will QA

[pkarman]

In general this looks good and doesn't seem to introduce any regressions.

There are some bugs though. Notably, an empty "Approver" field does not seem to trigger the "required" check. At first glance this seems to be because the HAML markup for that particular field is different than the others.

Likewise, empty "Building Code" and "Vendor" dropdown fields are not caught as required either.

Server-side validation still works as expected, though, so this might be acceptable in this first pass.
I'd be willing to merge this as a baseline implementation, and then open some bug stories to describe the missing pieces. Or, I can reject the existing story and you can give it another pass. Up to you @afeld.

[afeld]

Yeah, unfortunately client-side validation doesn't work with Selectize fields (selectize/selectize.js#733). Client-side validation is a convenience, so I personally don't think it's a blocker if it doesn't work across every field.