In order to check the test-coverage of Neo, we used the figleaf tool. The usage
(for a complete neo test suite) is :

Download and install figleaf : http://darcs.idyll.org/~t/projects/figleaf/doc/
$ figleaf neotestrunner -u (it will generate a .figleaf file)
$figleaf2html .figleaf (to convert .figleaf file in html pages)
$firefox html/ (to read the results)

Each one of the page contains Neo code, which the following colours :
Green : Executed code during test suite
Red : Unexecuted code
Black : Comments and "unused" lines

In order to check only needed neo file, you should specify the following options:
figleaf -i : ignore python libraries
figleaf2html -f : allows to specify a list of check-needed files
For stats, you can also check the index.html page, which indicated which
percentage of test-coverage.