Q: Migrating from testacular to karma I finally decided to migrate from testacular (0.4.0) to karma 0.8.5. My tests are Jasmine written in CoffeeScript. 
Here's the output of karma start path/to/karma.conf.js:
INFO [karma]: Karma server started at http://localhost:9876/
INFO [launcher]: Starting browser Chrome
INFO [Chrome 26.0 (Mac)]: Connected on socket id MOOnxLR89NKLGrrzbTI_

Chrome 26.0 (Mac) ERROR
Uncaught SyntaxError: Unexpected string
at /Users/genghis/Projects/chirper/client/test/spec/authenticationSpec.coffee:1
Chrome 26.0 (Mac): Executed 0 of 0 ERROR (1.246 secs / 0 secs)

Looking at the debugger console, there are similar errors for each test file. I've configured preprocessors, but it seems coffeescript is not being compiled? Here's my karma.conf.js:
basePath = '';

files = [
  JASMINE,
  JASMINE_ADAPTER,
  '../app/components/angular/angular.js',
  '../app/components/angular-mocks/angular-mocks.js',
  '../app/scripts/*.js',
  '../app/scripts/**/*.js',
  '../app/components/socket.io-client/dist/socket.io.js',
  '../test/spec/**/*.coffee'
];

exclude = [];
reporter = 'progress';
port = 9876;
runnerPort = 9100;
colors = true;
logLevel = LOG_INFO;
autoWatch = true;
browsers = ['Chrome'];
singleRun = false;

preprocessors = {
  '**/*.coffee': 'coffee'
};

Any ideas? Thanks in advance!
UPDATE: 
I can reproduce the error by running the CS test file with node cli. So obviously the coffeescript isn't getting compiled. The first line of the file (which fails) looks like this:
describe 'Authentication', ->


A: Edit: Try changing 'coffee' to ['coffee'] when specifying preprocessors.
For future people:
I struggled with this too.
I couldn't tell you the exact fix that made it work, but here's my config file. (It's in coffeescipt, but shouldn't make a difference, other than saving it as .coffee).
Notice I've explicitly set plugins, coffeePreprocessor, preprocessors, and a concrete value for basePath.
# Karma configuration

module.exports = (config) ->
    config.set({

        basePath: '../',

        frameworks: ['jasmine'],

        preprocessors: {
          '**/*.coffee': ['coffee']
        },

        coffeePreprocessor: {
          # options passed to the coffee compiler
          options: {
            bare: true,
            sourceMap: false
          },
          # transforming the filenames
          transformPath: (path) ->
            return path.replace('.js', '.coffee')
        },

        files: [
          'app/assets/vendor/angular.js'
          'app/assets/vendor/angular-mocks.js'
          'app/assets/javascript/*.coffee'
          'spec/clientjs/**/*Spec.*',

        ],

        reporters: ['progress'],

        port: 9876,

        colors: true,

        logLevel: config.LOG_INFO,


        plugins: [
            'karma-coffee-preprocessor',
            'karma-jasmine',
            'karma-chrome-launcher']

        autoWatch: true,

        browsers: ['Chrome'],

        captureTimeout: 60000,

        singleRun: false
    })


A: reporter = 'progress';
should be
reporters = ['progress'];
Also, you're error lies in spec/authenticationSpec.coffee
