Just want to add couple of points here for TestNG:
1. For TestNG, ${FAILED_TESTS} is giving No Tests Ran.
2. The following results page is not read by this plug-in:
${FILE, path="http://server:port/jenkins/job/<job_name>/<build_number>/"} ---> Null Pointer exception is thrown....
Please Note: Above URL is the place where the TestNG Results are displayed [We are unable to send this in the e-mail] --> presently users need to click on the link & then this data is shown!! [a bit of extra work]
--> It would be great if we could send the data (as mentioned in the attachment) in the e-mail.
This is an improvement request and not a bug.
You can still configure TestNG to produce JUnit compatible output.