The upstream repository clearly has tests, and they seems reasonable enough. Please fix the package to run them. While at it, you can also bump it to the new 1.0.0 release and clean up the ebuild.
Tests added with this commit https://gitweb.gentoo.org/repo/gentoo.git/commit/?id=54b4554d5547079e070f9840e69d3310888de0fb Latest version is in tree