how to fix images causing "karma WARN [web-server]: 404"?

I figured it out through random trial and error. Apparently you have to use the magic word "base" in your path.

proxies: {
  '/fake.png': '/base/spec/javascripts/fixtures/assets/fake.png'
}

now it works, but let's be honest, prepending "/base" just seems like nonsense.

If you don't care about showing the actual image in the tests this is enough:

proxies: {
  '/fake.png': ''
}