How to get better test reports in the console?

Just another detail - if you keep the default reporter 'progress' in the karma.config.js, like below:

reporters: ["progress", "spec"]

or another console reporter, the "spec" reporter output won't work.

You should keep only the "spec" one, or the "spec" with other browser reporters. For example:

reporters: ["spec", "coverage"]

Fixed by installing the karma-spec-reporter

npm install karma-spec-reporter --save-dev

and adding this my karma.config.js

reporters: ['spec'],

According to karma documentation

By default, Karma loads all NPM modules that are siblings to it and their name matches karma-*.

but some users have had to add the following to their config

plugins: ['karma-spec-reporter']

I wrote a reporter to make the output more readable: karma-helpful-reporter

Has some nice customization options: https://github.com/whyboris/karma-helpful-reporter

Instal instructions inside, basically npm install --save-dev karma-helpful-reporter and then add to the Karma configuration plugins section:

plugins: [ 
  require('karma-helpful-reporter')
],
reporters: [ 'helpful' ],