gistfile1.js

// base path, that will be used to resolve files and exclude
basePath = '..';

// list of files / patterns to load in the browser
// chai is from https://github.com/chaijs/chai - the main chai.js file in the root
files = [
    MOCHA,
    MOCHA_ADAPTER,

    // stubs come first so they can be available when all the units need them
    'test/rtd/lib/*-stubs.js',
    'test/stubs/*.coffee',
    'test/vendor/chai.js',

    // Run setup
    'test/unit/setup/*.coffee',

    // the reason we load unit tests next is because they don't depend on the app. On the contrary,
    // they set mocks ahead of time for the units so they have to be loaded first
    'test/unit/**/*.js',
    'test/unit/**/*.coffee',


    // Models have to load next as they're auto-stubbed by RTD
    'app/models/**/*.js',
    'app/models/**/*.coffee',

    // simulate loading order of meteor folder structure
    'app/lib/**/*.js',
    'app/client/lib/**/*.js',
    'app/server/lib/**/*.js',

    'app/src/client/**/*.coffee',

    // now all the dependencies have been sorted, the app code can be loaded
    'app/**/*.js'
];


// list of files to exclude
exclude = [
    '**/3rd/**/*.js',
    '**/istanbul-middleware-port/**/*',
    'karma.conf.js',
    'app/.meteor/local',
    'app/server/fixture.js',
    'app/packages/**/*',
    'app/public/**/*'
];

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

coverageReporter = {
    type: 'text-summary',
    dir: 'build/reports/coverage/',
    file: 'coverage.txt'
};

// test results reporter to use
// possible values: 'dots', 'progress', 'junit'
reporters = ['dots', 'coverage'];


// web server port
port = 9876;


// cli runner port
runnerPort = 9100;


// enable / disable colors in the output (reporters and logs)
colors = true;


// level of logging
// possible values: LOG_DISABLE || LOG_ERROR || LOG_WARN || LOG_INFO || LOG_DEBUG
logLevel = LOG_DISABLE;

// enable / disable watching file and executing tests whenever any file changes
autoWatch = false;


// Start these browsers, currently available:
// - Chrome
// - ChromeCanary
// - Firefox
// - Opera
// - Safari (only Mac)
// - PhantomJS
// - IE (only Windows)
browsers = ['PhantomJS'];


// If browser does not capture in given timeout [ms], kill it
captureTimeout = 60000;


// Continuous Integration mode
// if true, it capture browsers, run tests and exit
singleRun = false;

Sam - you can see we haven't used coffee for this. Didn't know you were supporting coffee for the conf file. Maybe that just comes for free from karma?

But if you did it in coffee, it would be very similar. Here's a converted version of this file:
https://gist.github.com/philcockfield/5888622