anchor.diff:  | `is_false` | evaluates to false
   | `is_null` | equals null
   | `is_non_null` | is a non null value
  +| `is_not_null` | d:o
   ||
   | `is_equal_to(value)` | '== value'
   | `is_not_equal_to(value)` | '!= value'
  
positive.code: are empty. (You will get strange errors if you don't!)
  
  NOTE: We are using the name "Cgreen" as the SUT in these first
  examples, as if *Cgreen* itself was the object or class we wanted to
  test or describe.
  
  I am assuming you have the *Cgreen* folder in the include search
  
negative.code: Writing Basic Tests
  ~~~~~~~~~~~~~~~~~~~
  
  *Cgreen* tests are like C, or C++, functions with no parameters and
  no return value. To signal that they actually are tests we mark them
  with the `Ensure` macro. Here's an example...
  
  [source,c]
  -----------------------------
  