changed the logic when exist settings.workingdirectory

[jfernandeze]

Now you can, for example, use this configuration:

var settings = new KarmaStartSettings
{
   ConfigFile = "ClientApp/test/karma.conf.js",                       
   RunMode = KarmaRunMode.Local,
   WorkingDirectory = "src/Webs/WebSpa"
 };

[gep13]

Closing this in favour of #9