This has been submitted as a Insight Journal Article:
http://hdl.handle.net/10380/3116

If we look at the XML for the CDash (http://public.kitware.com/Wiki/CDash:XML), specifically the file
which describes the valid xml for test (ValidationSchemata/Text.xsd)
we see the NamedMeasurement tag. This is the field that is displayed
for the test. It can show a variety of types with the "type"
attribute. Previously Dart defined the following types:
"numeric/integer", "numeric/float", "numeric/double",
"numeric/boolean", "text/string", "text/plain", "image/png",
"image/jpeg".

The way this testing system works is each test produces XML output of
"NamedMeasurements". This XML is then compared against a XML
baseline. Then any difference will be reported and sent to CDash via
ctest. To produce a baseline, the output of the test should be
carefully manually verified, then attributes added to the XML tags to
describe how to do comparisons.