How to unit test this

mapform.js

/* How does one unit test this? */
$(document).ready(function() {
  $('#map-searchform .searchform-fields label').inFieldLabels();

  $('#map-search-form').submit(function (e) {
    e.preventDefault();
    $('#map').map_control().find($('#map-search-terms').val());
  });
});

I would recommend using a view system like backbone so that you can test the individual bits of functionality.

I see about 7 different responsibilities being done in this one chunk of code

1. Setting a function to be called on dom ready
2. handling the map search forms submit event
3. Assigning a handler for the map search forms submit event
4. retrieving data from the map-search-terms field

There also feels like a smidge of inappropriate intimacy. $('#map').map_control().find() means that this on load method (which should probably be named instead of anonymous) has to know about the inner workings of whatever it is map_control returns, which becomes a law of demeter violation.

All this to say, the issue isn't a difficulty in testing JQuery, but our 'normal' method of writing javascript is so opposed to good design practices that it winds up being very difficult to test.

I test drove a refactoring of your code, see here: https://gist.github.com/1216413

This is testing in absolute isolation, using spys and what not with jasmine.

This also revealed a weakness in jasmine (or my understanding of jasmine) where it doesn't seem possible to assert upon what a spy method was called on...