Karma Browserify Dependency Injection not working

So i have recently added the Karma test runner to my commonJS project but when trying too access the app in my unit tests it claims.

[$injector:nomod] Module 'app' is not available! You either misspelled the module name or forgot to load it.

this is my configuration: karma.conf.js

// Karma configuration
// Generated on Tue Feb 10 2015 10:08:30 GMT-0500 (EST)

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: http://ift.tt/1ft83uu
        frameworks: ['browserify','mocha'],

        // list of files / patterns to load in the browser
        files: [
            'public/bower_components/angular/angular.js',
            'public/bower_components/angular-route/angular-route.js',
           'public/bower_components/angular-mocks/angular-mocks.js',

            'public/js/app.js', //(concatted file including all the scripts that make the app
            'test/unit/client/*_tests.*',
            'test/unit/client/test-main.js'
        ],

        browserify: {
            debug: true
        },

        // these plugins will be require() by Karma
        plugins: [
            'karma-browserify',
            'karma-mocha',
            'karma-chai',
            'karma-firefox-launcher',
            'karma-spec-reporter'
        ],

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

        // preprocess matching files before serving them to the browser
        // available preprocessors: http://ift.tt/1gyw6MG
        preprocessors: {
        },

        // test results reporter to use
        // possible values: 'dots', 'progress'
        // available reporters: http://ift.tt/1ft83KQ
        reporters: ['spec'],

        // 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: false,

        // start these browsers
        // available browser launchers: http://ift.tt/1ft83KU
        browsers: ['Firefox'],

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

test-main.js

var tests = [];

for (var file in window.__karma__.files) {
    if (window.__karma__.files.hasOwnProperty(file)) {
       // console.log(file);
        if (/\_tests\.js$/.test(file)) {
            tests.push(file);
        }
    }
}

unit_tests.js

describe("Remote Retro Module Unit Tests", function () {
    //var module;     
    var ctrl, scope, $httpBackend, service;

    // Load the module with Controller to be tested
    beforeEach(module('app'));

    beforeEach(inject(function ($controller, $rootScope, _service_, _$httpBackend_, _$http_) {

        // Create a new scope that's a child of the $rootScope
        scope = $rootScope.$new();
        service = _service_;
        $httpBackend = _$httpBackend_;
    }));