When using recent TestNG versions (> 6.8.21) with Arquillian, failing tests are accidentally reported as passing.
A reproducer can be found at https://github.com/gunnarmorling/arquillian-testng-bug.
There is a single test which is expected to fail, but it actually is reported as successful with TestNG 6.11. It is reported as failed as expected with 6.8.21. Run mvn clean install for reproducing.