The (phantom) tests are hard to run

[wolframkriesing]

I tried to install phantom and run the tests via make test, it seems this is so out of date that this needs some love.

[wolframkriesing]

related to https://github.com/uxebu/bonsai/tree/switch-to-yarn
just in case you run into this error

# ./node_modules/.bin/phantomjs --version
internal/child_process.js:289
  var err = this._handle.spawn(options);
                         ^

TypeError: Bad argument

this is the bug, yarnpkg/yarn#1607
I got it working by rm -Rf node_modules; yarn