Can not run tests

[noherczeg]

Runnig npm test results in the following error:

> find . -name '*.test.js' | xargs ./node_modules/.bin/mocha --compilers js:babel-register

module.js:471
    throw err;
    ^

Error: Cannot find module '../util.js'
    at Function.Module._resolveFilename (module.js:469:15)
    at Function.Module._load (module.js:417:25)
    at Module.require (module.js:497:17)
    at require (internal/module.js:20:19)
    at Object.<anonymous> ...

And is due to the fact that in the buildt build/modules/@shrine/util/util.test.js file has a wrong path for the source: var _util = require('../util.js');.