Configuration to finally get Karma working with RequireJS. After Karma is installed, run `karma start karma.config.js`

karma.config.js

// Karma configuration
// Generated on Wed Jul 22 2015 18:41:14 GMT+0900 (Tokyo Standard Time)

module.exports = function(config) {
  config.set({

    // base path that will be used to resolve all patterns (eg. files, exclude)
    basePath: '',


    // frameworks to use
    // available frameworks: https://npmjs.org/browse/keyword/karma-adapter
    frameworks: ['jasmine', 'requirejs'],


    // list of files / patterns to load in the browser
    // test-main.js configures paths for RequireJS
    // All tests are matched by second pattern
    // All libraries and game code are matched by third
    files: [
      'test-main.js',
      {pattern: 'src/**/test/javascript/*Spec.js', included: false},
      {pattern: 'src/main/webapp/**/*.js', included: false}

    ],


    // list of files to exclude
    // Exclude our main.js so RequireJS doesn't try to start with the production configuration
    exclude: [
        'src/main/webapp/app/main.js'
    ],

    // preprocess matching files before serving them to the browser
    // available preprocessors: https://npmjs.org/browse/keyword/karma-preprocessor
    preprocessors: {
    },

    // test results reporter to use
    // possible values: 'dots', 'progress'
    // available reporters: https://npmjs.org/browse/keyword/karma-reporter
    reporters: ['progress'],

    // web server port
    port: 9876,

    // enable / disable colors in the output (reporters and logs)
    colors: true,

    // level of logging
    // possible values: config.LOG_DISABLE || config.LOG_ERROR || config.LOG_WARN || config.LOG_INFO || config.LOG_DEBUG
    logLevel: config.LOG_INFO,

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

    // start these browsers
    // available browser launchers: https://npmjs.org/browse/keyword/karma-launcher
    browsers: ['Chrome'],

    // Continuous Integration mode
    // if true, Karma captures browsers, runs the tests and exits
    singleRun: false
  })
}

test-main.js

// Replacement main.js for Karma running with RequireJS
// Finally figured out after hours and hours of searching due to my non-standard (?)
// directory structure for this project. Modified from the default Karma setup

/* Directory structure like this:

base
|--karma.config.js
|--test-main.js
|--src
   \--main
      `--webapp
         |--app
         |  |--models
         |  |  `--gameModel.js
         |  |--main.js
         |  |--game.js
         |  |--game.html
         |  |--*.html
         |  `--*other*.js
         `--lib
            |--accounting
            |  `--accounting.js
            |--bootstrap
            |  `--bootstrap.js
            `--require
               `--require.js
   |--test
      `--javascript
         `-gameSpec.js

*/

var allTestFiles = [];
var TEST_REGEXP = /(spec|test)\.js$/i;

// Get a list of all the test files to include
Object.keys(window.__karma__.files).forEach(function(file) {
  if (TEST_REGEXP.test(file)) {
    // Normalize paths to RequireJS module names.
    // If you require sub-dependencies of test files to be loaded as-is (requiring file extension)
    // then do not normalize the paths
    var normalizedTestModule = file.replace(/^\/base\/|\.js$/g, '');
    allTestFiles.push(normalizedTestModule);
  }
});

require.config({
  // Karma serves files under /base, which is the basePath from your config file
  baseUrl: '/base',
  
  // Need to add paths here since otherwise Karma searches for them in /base
  // Can't put baseUrl to be src/main/webapp/lib or else it can't find the tests
  paths: {
    'text': 'src/main/webapp/lib/require/text',
    'durandal': 'src/main/webapp/lib/durandal/js',
    'plugins': 'src/main/webapp/lib/durandal/js/plugins',
    'transitions': 'src/main/webapp/lib/durandal/js/transitions',
    'knockout': 'src/main/webapp/lib/knockout/knockout-3.1.0',
    'koMapping': 'src/main/webapp/lib/knockout/knockout.mapping-2.4.1.min',
    'jquery': ['src/main/webapp/lib/jquery/jquery-1.9.1'],
    'accounting': 'src/main/webapp/lib/accounting/accounting.min',
    'gameData': 'src/main/webapp/app/gameData.min',
    'models/gameModels': 'src/main/webapp/app/models/gameModels'
  },

  // dynamically load all test files
  deps: allTestFiles,

  // we have to kickoff jasmine, as it is asynchronous
  callback: window.__karma__.start
});

@master-elodin for whenever you want to get Karma set up