This tests shows a way to handle peer dependencies.
Upon observation of behaviors of npm install and npm prune we found that, in the case that some package peerDepends AND devDepends on another package, upon running npm prune --production, the peerDepending package is not removed.
One would expect it to be removed since it is a devDependency, but somehow it is getting excluded due to existing as peerDependecy.
This is not a big deal in general. But a great discovery for building packages that require their peerDependencies for testing purposes or for usage in bundled demos that use dependencies from node_modules.