Write browser tests

[bertday]

Goal
Write browser tests to make sure our code is working as expected across different browsers before publishing new versions of Mapboard. Ideally, these tests should be automated and prevent failing code from being pushed to production.

Problem
As Mapboard gets more complex, we're starting to see a pattern of fixing one thing and breaking another (regressions). Having automated tests will prevent a lot of these.

Scope
We can pilot a testing workflow by targeting a single tab in Atlas. The Deeds tab is especially prone to errors, since it has more logic and data sources than the others. Let's start by writing a test that just checks the Deeds tab for the right number of parcel tabs, and makes sure the Parcel Details section is showing up with good data.

Once we're comfortable with that test, we can start writing more for the other tabs, especially those with conditional logic (e.g. Condominiums).

Steps

1. Write a test that can be run locally with Nightwatch.
2. Integrate the Nightwatch test with BrowserStack Automate and/or Travis to run the test automatically for all pushes to the master branch. There's a document here on that. We'll also want to configure Travis to kick off BrowserStack.

/cc @ajrothwell @regisshogan