Select DOM elements with wildcard syntax

- DOM lookups were being done with non-existent literal selectors, so it
  was returning empty lists. As assertions were to be made while
  iterating over the list of elements, nothing was actually being
  verified.

- Common code has been centralized in the setup function. By declaring
  CSS selectors once, we minimize the odds of inadvertently using the
  wrong selector, as happened here.

- Had these tests actually been iterating over a non-empty list, this
  would have thrown undefined exceptions. jQuery.each calls its handler
  with an index and an item/object as the arguments. However, the object
  is a DOM-object, not a jQuery-object.  These tests break, as they had
  assumed the latter.