Module not found: Error: Can't resolve 'avoriaz'

I'm new to Vue and am learning how to test it from this tutorial. I've reached the end of the tutorial but am getting a strange error on the last step of using avoriaz:

ERROR in ./test/unit/specs/list.spec.js
Module not found: Error: Can't resolve 'avoriaz' in 
'/local/path/to/vuejs-
testing/test/unit/specs'
 @ ./test/unit/specs/list.spec.js 3:15-33
 @ ./test/unit/specs \.spec$
 @ ./test/unit/index.js

Here's the relevant code in my test file:

import { mount } from 'avoriaz';
import List from '@/components/List';
import Vue from 'vue';
...

And my package.json file:

  ...
  },
  "dependencies": {
    "vue": "^2.3.3",
    "vue-router": "^2.6.0"
  },
  "devDependencies": {
    "autoprefixer": "^7.1.2",
    "avoriaz": "^2.6.3",
  ...

I tried removing my node_modules directory and package-lock.json and reinstalling everything with npm install to no avail.

Any ideas as to what could be causing this, and how to resolve it?