What EICAR test file are you using?
If you have download the standard test file from https://www.eicar.org/ and uploaded that to your site to test my plugin then I can confirm that it will not identify that file as a threat, because it isn’t a threat to your site. Those test files are for binary malware of the kind that would be found on your PC by Windows based Anti-Malware software. Web-based malware is quite different and my plugin is designed to look for malicious code that would be executed by your server not compiled binary code which will have not effect on your server ??
While binary malware cannot be remotely executed on a server and is therefore relatively safe to upload I would strongly advise you not to upload and know PHP threats or any other malicious CGI/Perl/Python code that that could be called remotely or accidentally executed on the server.
Please let me know if you have any more questions on any of this.
If I have misunderstood about what kind of EICAR test files you are using then please send me that file so that I can examine it and give you a better answer.
Aloha, Eli