Blubber currently installs node modules into a shared location, mostly so that the resulting Docker image layers are more cacheable (only changes to package.json invalidates the cache this way). Because of this setup, npm run cannot locate the executables for external node dependencies. (e.g. in Mathoid's case, npm test fails because it assumes mocha to be installed in the local node_modules directory.)

We should be able to work around this by having Blubber prepend the PATH environment variable with ${NODE_PATH}/.bin much like npm tries to do with the current working directory.