In the console example below:

"Found 0 test result(s).
Updating TestLink test cases.
No emails were triggered.
Finished: SUCCESS"

we can see that when no test results are found, the test link plug-in reports a "SUCCESS" status. I think it's wrong and a "FAILURE" status should be reported instead.

Fix proposal:
Just adding:
if (report.getTestsTotal()==0) {
build.setResult(Result.FAILURE);
}

in src/main/java/hudson/plugins/testlink/TestLinkBuilder.java
at the end of the perform method is sufficient in my case.

Best Regards,
Oscar