End to end Javascript driven unit tests #144
Description
We have to make a few assumptions about how the WKWebView API interprets Js objects when we injest a message. And we have gotten it wrong in at least one case.
It would be comforting to setup some tests that launch an actual web page with some Js that can exercise the real API in situ so that we can unit test using the actual input that would arrive from real world use of the Js polyfill.