Gulp-shell 'karma is not recognized by an internal or external command ...'

I use gulp to concat, minify and then test all my JS. I also want to include karma in it, but I can't get the gulp-shell 'karma start karma.conf.js' to work properly. Karma is added to the PATH as I can run this command from the same working directory as the gulpfile in Windows Shell without any problem. I can also run other commands correctly like "ls", "pwd", "npm --version" etc., but for some reason it doesn't recognize "karma".

I also got this launch on OSX correct, so this is a local problem to my machine. Any help would be appreciated.

gulp.task('run-karma', shell.task(['karma start karma.conf.js']));

      

        
        
        
      

    

mistake

 'karma' is not recognized as an internal or external command, 
 operable program or batch file.
 Error in plugin 'gulp-shell' Message:
   Command 'karma start karma.conf.js' failed with exit code 1