TestOutput
The TestOutput class holds a unit of output from
            a test to a specific output stream
            
                
Get the output type
            
Get the id of the test that created the output
            
Get the name of the test that created the output
            
Get the text
            
Construct with text, output destination type and
            the name of the test that produced the output.
            
Convert the TestOutput object to an XML string