I was recently investigating issue where iOS was constantly disconnecting, or timeouting when running remote tests in InfernoJS repository

It turned out that karma does not gzip the test bundles by default. Then I started looking for solution and found this small plugin

https://github.com/GreenGremlin/karma-gzip

After adding gzip plugin into karma pipeline test download + execution improved 30seconds

1m 57s -> 1m 28s Bundle size went down from 4MB -> 657kb

The plugin was not very popular so I thought maybe I should spread The word!

Hopefully this helped somebody! :-)