Test files contain ClamAV-Test-Signature.
You need unrar 3.0 to detect the test signature in test-failure.rar. Only
clamscan is able to scan this file (clamd only depends on libclamav which has
no support for the new RAR format). Please use clamscan --unrar, and it will
automatically switch to the unrar utility after an internal (libclamav's)
RAR module error.