Angular.js unitest a Directive with external template using html2js - Fail to load templates

I am trying to test a Directive which uses external template. I tried all the following solutions with no luck:

• ng-directive-testing

• How to test directives that use templateUrl and controllers?

• AngularJS + Karma + Ng-html2js => Failed to instantiate module ...html

I created a test directive (a simple div) and tested it using an inline 'template' and external 'templateUrl'. The inline solution works while the external doesn't:

   angular.module('AdUnit').directive('actionButton',function($location){
        return{
            scope:{
                actionName: '@'
            },
            restrict: 'E',
            //template: "<div ng-click='click()'>action button</div>",
            templateUrl: '/staticfiles/adunit/html/directives/actionButtonTemplate.html',
            controller: ['$scope', function($scope){
                $scope.click = function(){
                    $scope.$emit('ACTION_CLICK', $scope.actionName);
                }
            }]

        }
    });



    describe("Unit: Testing action button directive", function() {
    var elm, scope, linkFn;
    beforeEach(
        module('AdUnit')
    );

    beforeEach(module('/staticfiles/adunit/html/directives/actionButtonTemplate.html'));

    beforeEach(inject(function($rootScope, $compile) {
        elm = angular.element('<action-button action-name="post-action-0"></action-button>');
        scope = $rootScope;
        linkFn = $compile(elm);
        linkFn(scope);
        scope.$digest(); // have to digest to bring html from templateCache
        console.log('post compile',elm.html());// <== the html here still have {{}}
    }));

    it('should show a thumb',function() {

            console.log('post link',elm.html());// <== the html is bound

            expect(elm.text()).toBe("action button");

    });
});

My Karma config file:

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

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


    // frameworks to use
    frameworks: ['jasmine'],


    // list of files / patterns to load in the browser
    files: [
        'http://ajax.googleapis.com/ajax/libs/jquery/1.10.1/jquery.min.js',
        'http://ajax.googleapis.com/ajax/libs/angularjs/1.2.5/angular.min.js',
        'http://ajax.googleapis.com/ajax/libs/angularjs/1.2.5/angular-route.js',
        'http://code.angularjs.org/1.0.6/angular-mocks.js',
        '../html/*.html',
        '../html/directives/*.html',
        '../js/adUnit.js',
        '../js/controllers/*.js',
        '../js/directives/*.js',
        '../js/services/*.js',
        '../*.js',
         '../**.*.js',
         '**/*.tests.js'
    ],

    preprocessors : {
        '../html/**/*.html': ['ng-html2js']
    },

     /* ngHtml2JsPreprocessor: {
          'AdUnit': '/staticfiles/adunit/html/directives/actionButtonTemplate.html'
          *//*moduleName: '/staticfiles/adunit/html/directives/internalPlayerTemplate.html'*//*
      },*/

    // list of files to exclude
    exclude: [

    ],


    // test results reporter to use
    // possible values: 'dots', 'progress', 'junit', 'growl', 'coverage'
    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, currently available:
    // - Chrome
    // - ChromeCanary
    // - Firefox
    // - Opera (has to be installed with `npm install karma-opera-launcher`)
    // - Safari (only Mac; has to be installed with `npm install karma-safari-launcher`)
    // - PhantomJS
    // - IE (only Windows; has to be installed with `npm install karma-ie-launcher`)
    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
  });
};

I keep getting the following error:

Failed to instantiate module /staticfiles/adunit/html/directives/actionButtonTemplate.html due to:
Error: [$injector:nomod]

Any help will be appreciated!

EDIT: @MK Safi's answer solved my problem. I was missing the following:

 ngHtml2JsPreprocessor: {
     'moduleName': 'Templates',

     // Function that transforms the path to look exactly like
     // you have it in templateUrl in your Angular code
     //
     // Mine looks like this
     cacheIdFromPath: function(filepath) {
         return filepath.match(/\/staticfiles\/adunit\/html\/directives\/.*\.html/);
     }
  },

and before each test:

 beforeEach(module('Templates'));

it is important for the regular expression to point to the same path as the directive's "templateUrl", since html2js will cache those templates using this path (see html2js for more details about that)