These are Eicar anti-virus test files downloaded from http://www.eicar.com.
clamscan is able to detect Eicar-Test-Signature in all test files. Please use

$ clamscan -r --unzip

in this directory. It should find 3 viruses. These files are not generated
properly - compression algorithm has to small information (only eicar.com file)
to build proper tree and archives itselfs contain full signature - try to scan
raw zips:

$ clamscan
