If you update to karma 0.5.0 and get the following error: Config file must export a function!

LOG_INFO is not supported anymore.
  Please use `karma.LOG_INFO` instead.
ERROR [config]: Config file must export a function!
  module.exports = function(config) {
    config.set({
      // your config
    });
  };

Basically, you need to replace your old karma.conf.js file with the new format.

// Karma configuration
// Generated on Fri Jul 05 2013 01:57:57 GMT-0400 (EDT)
/*global basePath:true, exclude:true, reporters:true, files:true*/
/*global coverageReporter:true, junitReporter:true, reporters:true,
preprocessors:true, frameworks:true*/
/*global port:true, runnerPort:true, colors:true, logLevel:true*/
/*global autoWatch:true, browsers:true, captureTimeout:true, singleRun:true*/
/*global JASMINE:true, JASMINE_ADAPTER:true, REQUIRE:true, REQUIRE_ADAPTER:true*/
/*global LOG_INFO:true*/
module.exports = function(config) {
	config.set({

		// base path, that will be used to resolve files and exclude
		// basePath: 'tmp/public',
		basePath: '',

		// list of files / patterns to load in the browser
		files: [
			{pattern: 'lib/jquery/jquery.js', included: false},
			{pattern: 'lib/requirejs/require.js', included: false},
			{pattern: 'src/*.js', included: false},
			{pattern: 'test/spec/*-spec.js', included: false},

			// helpers & fixtures for jasmine-jquery
			{ pattern: 'test/helpers/*.js', included: true },
			'test/test-main.js',
		],

		frameworks: ['jasmine', 'requirejs'],

		plugins: [
			'karma-qunit',
			'karma-jasmine',
			'karma-requirejs',
			'karma-coverage',
			'karma-phantomjs-launcher',
			'karma-chrome-launcher',
			'karma-firefox-launcher',
			'karma-safari-launcher'
		],

		preprocessors: {
			'**/src/*.js': 'coverage'
		},

		// list of files to exclude
		exclude: [],

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

		coverageReporter: {
			type : ['text'],
			dir : 'coverage/'
			// type: 'cobertura',
			// dir: 'coverage/',
			// file: 'coverage.xml'
		},

		// 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: config.LOG_DISABLE,

		// enable / disable watching file and executing tests whenever any file changes
		autoWatch: true,

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

		// 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
	});
};