[2468] Ava test fail from UglifyJS - Unexpected token: punc (()

My project: https://github.com/KyleTryon/VidFireBlog

Based on: https://github.com/contentful/blog-in-5-minutes/

I have just added AVA testing trying to follow this example: https://nuxtjs.org/examples/testing/

When running the test script I get the following error

Full error:

ERROR in pages/blog/_slug.2ac1837fe29f7bf12a78.js from UglifyJs
Unexpected token: punc (() [pages/blog/_slug.2ac1837fe29f7bf12a78.js:682,11]

ERROR in pages/blog/index.93c50088bce151b8ccd3.js from UglifyJs
Unexpected token: punc (() [pages/blog/index.93c50088bce151b8ccd3.js:1142,11]

ERROR in pages/blog/articlePage.0dd516829d3a25f54ebd.js from UglifyJs
Unexpected token: punc (() [./plugins/contentful.js:9,2][pages/blog/articlePage.0dd516829d3a25f54ebd.js:5960,14]

ERROR in app.80d410dd093a7d887898.js from UglifyJs
Unexpected token: punc (() [./.nuxt/components/no-ssr.js:8,2][app.80d410dd093a7d887898.js:19,6]
  ✖ Init Nuxt.js Rejected promise returned by test

  1 test failed

  Init Nuxt.js

  /mnt/e/projects/VidFireBlog/VidFireBlog/node_modules/nuxt/lib/builder/builder.js:498

  Rejected promise returned by test. Reason:

  Error {
    message: 'Webpack build exited with errors',
  }

  node_modules/nuxt/lib/builder/builder.js:498:27
  emitRecords.err (node_modules/webpack/lib/Compiler.js:265:13)
  Compiler.emitRecords (node_modules/webpack/lib/Compiler.js:371:38)
  emitAssets.err (node_modules/webpack/lib/Compiler.js:258:10)
  applyPluginsAsyncSeries1.err (node_modules/webpack/lib/Compiler.js:364:12)
  next (node_modules/tapable/lib/Tapable.js:218:11)
  Compiler.compiler.plugin (node_modules/webpack/lib/performance/SizeLimitsPlugin.js:99:4)
  Compiler.applyPluginsAsyncSeries1 (node_modules/tapable/lib/Tapable.js:222:13)
  Compiler.afterEmit (node_modules/webpack/lib/Compiler.js:361:9)
  require.forEach.err (node_modules/webpack/lib/Compiler.js:350:15)
  node_modules/async/dist/async.js:473:16
  iteratorCallback (node_modules/async/dist/async.js:1050:13)
  node_modules/async/dist/async.js:958:16
  node_modules/graceful-fs/graceful-fs.js:43:10

npm ERR! code ELIFECYCLE
npm ERR! errno 1
npm ERR! vidfire-blog@1.0.0 test: `ava --serial --verbose`
npm ERR! Exit status 1
npm ERR!
npm ERR! Failed at the vidfire-blog@1.0.0 test script.
npm ERR! This is probably not a problem with npm. There is likely additional logging output above.

npm ERR! A complete log of this run can be found in:
npm ERR!     /home/kyle/.npm/_logs/2017-12-27T22_19_13_116Z-debug.log

I have seen a few other issues online that are similar but no clear answers.