anchor.diff:  an optional argument.  The entire test suite will be searched for the
   named test.  This trick also saves us a recompile when we debug.
   
  -We've placed each test suite in it's own file, but that is not
  +We've placed each test suite in its own file, but that is not
   necessary.  We could build several test suites in the same file, even
   nesting them.  We can even add mixtures of test functions and test
   suites to the same parent test suite.  Loops will give trouble,
  
positive.code: 
  Where are the assertions?
  
  Unlike our earlier stub, 'reader()' can now check it's parameters.  In
  object oriented circles, an object that checks it's parameters as well
  as simulating behaviour is called a mock object.  By analogy
  'reader()' is a mock function, or mock callback.
  
  
negative.code: and 'reporter_finish()' functions is optional, I want to
  make use of some of the facilities later.
  
  Our output meanwhile, is making its first tentative steps...
  
  [source,xml]
  -----------------------
  