High fidelity prototyping using a mock back-end. Include angular-mocks in your script includes after angular. Demo: http://codepen.io/kennethlynne/pen/lJbce

angular-mock-backend.js

'use strict';

angular.module('yourApp')
    .constant('Config', {
        viewDir:               'views/',
        API: {
            useMocks:           true,
            fakeDelay:          2000,
            protocol:           window.location.protocol.split(':')[0],
            host:               window.location.hostname,
            port:               String(window.location.port || 80),
            path:               '/api',
        }
    })
    .config(function(Config, $provide) {
        //Decorate backend with awesomesauce
        if(Config.API.useMocks) $provide.decorator('$httpBackend', angular.mock.e2e.$httpBackendDecorator);
    })
    .config(function ($httpProvider, Config) {
        if(!Config.API.useMocks) return;
 
        $httpProvider.interceptors.push(function ($q, $timeout, Config, $log) {
            return {
                'request': function (config) {
                    $log.log('Requesting ' + config.url, config);
                    return config;
                },
                'response': function (response) {
                    var deferred = $q.defer();
 
                    if(response.config.url.indexOf(Config.viewDir) == 0) return response; //Let through views immideately
 
                    //Fake delay on response from APIs and other urls
                    $log.log('Delaying response with ' + Config.API.fakeDelay + 'ms');
                    $timeout(function () {
                        deferred.resolve(response);
                    }, Config.API.fakeDelay);
 
                    return deferred.promise;
                }
 
            }
        })
 
    })
    .factory('APIBase', function (Config) {
        return (Config.API.protocol + '://' + Config.API.host + ':' + Config.API.port  + Config.API.path + '/');
    })
    .constant('regexEscape', function regEsc(str) {
        //Escape string to be able to use it in a regular expression
        return str.replace(/[\-\[\]\/\{\}\(\)\*\+\?\.\\\^\$\|]/g, "\\$&");
    })
    .run(function (Config, $httpBackend, $log, APIBase, $timeout, regexEscape) {
 
        //Only load mocks if config says so
        if(!Config.API.useMocks) return;
        
        var collectionUrl = APIBase + 'tags';
        
        var IdRegExp = /[\d\w-_]+$/.toString().slice(1, -1);
        var QueryRegExp = /[\d\w-_\.%\s]*$/.toString().slice(1, -1);
        
        var id = 0;

        var TagRepo = {};
        TagRepo.data = [
            {id: id++, text:'Javascript'},
            {id: id++, text:'Angular'},
            {id: id++, text:'.NET'},
            {id: id++, text:'Java'},
            {id: id++, text:'Firebase'},
            {id: id++, text:'Ember'},
            {id: id++, text:'generator-angular-xl'},
        ];
        TagRepo.index = {};
 
        angular.forEach(TagRepo.data, function(item, key) {
            TagRepo.index[item.id] = item; //Index messages to be able to do efficient lookups on id
        });
 
        //GET tag/
        $httpBackend.whenGET(collectionUrl).respond(function(method, url, data, headers) {
            $log.log('Intercepted GET to tag', data);
            return [200, TagRepo.data, {/*headers*/}];
        });

        //GET tag/<id>
        $httpBackend.whenGET( new RegExp(regexEscape(collectionUrl + '/') + IdRegExp ) ).respond(function(method, url, data, headers) {
            $log.log('Intercepted GET to tag/id');
            var id = url.match( new RegExp(IdRegExp) )[0];
            
            var Tag = TagRepo.index[id];
            
            if (!Tag) {
                return [404, {} , {/*headers*/}];
            }
            

            return [200, Tag, {/*headers*/}];
        });
        
        //POST tag/
        $httpBackend.whenPOST(collectionUrl).respond(function(method, url, data, headers) {
            $log.log('Intercepted POST to tag', data);
            var Tag = angular.fromJson(data);

            Tag.id = id++;
            TagRepo.data.push(Tag);
            TagRepo.index[Tag.id] = Tag;

            return [200, Tag, {/*headers*/}];
        });

        //GET tag/search?q=<query>
        $httpBackend.whenGET( new RegExp(regexEscape(collectionUrl + '/search?q=') + QueryRegExp ) ).respond(function(method, url, data, headers) {
            $log.log('Intercepted GET to tag/search');
            var term = url.match( new RegExp(QueryRegExp) )[0] || '';

            var hits = TagRepo.data.filter(function (tag) {
                return tag && typeof tag.text == 'string' && tag.text.toLowerCase().indexOf(term.toLowerCase()) >= 0;
            });

            return [200, hits, {/*headers*/}];
        });

        //PUT tag/<id>
        $httpBackend.whenPUT( new RegExp(regexEscape(collectionUrl + '/') + IdRegExp ) ).respond(function(method, url, data, headers) {
            $log.log('Intercepted PUT to tag');
            var id = url.match( new RegExp(IdRegExp) )[0];

            if (!TagRepo.index[id]) {
                return [404, {} , {/*headers*/}];
            }

            var Tag = TagRepo.index[id] = angular.fromJson(data);

            return [200, Tag, {/*headers*/}];
        });

        //DELETE tag/<id>
        $httpBackend.whenDELETE( new RegExp(regexEscape(collectionUrl + '/') + IdRegExp ) ).respond(function(method, url, data, headers) {
            $log.log('Intercepted DELETE to tag');
            var id = url.match( new RegExp(IdRegExp) )[0];

            var Tag = TagRepo.index[id];
            
            if (!Tag) {
                return [404, {} , {/*headers*/}];
            }
            
            delete TagRepo.index[Tag.id];
            
            var index = TagRepo.data.indexOf(Tag);
            TagRepo.data.splice(index, 1);
            
            return [200, Tag , {/*headers*/}];
        });

    });

Thanks for this. Is it working for you when Angular is trying to fetch a view? I see there's a code that deals with it, but I'm still getting Unexpected request: GET views/main.html errors.

Found the problem. The gist is currently missing this statement, in the end of all the $httpBackend.when*:

// pass through everything else.
$httpBackend.whenGET(/\/*/).passThrough();

Thank you for clarifying. :)

Here is a working example: http://codepen.io/kennethlynne/pen/lJbce

I'm using some parts of your code and I'm having the same problem @amitaibu had, tried his solution with no success.

the response function it is even called.

'use strict';

angular.module('blakerFrontApp')
.config(function($provide) {
  $provide.decorator('$httpBackend', angular.mock.e2e.$httpBackendDecorator);
})
.config(function ($httpProvider) {
  $httpProvider.interceptors.push(function($q, $timeout, $log) {
    return {
      'request': function(config) {
        var deferred = $q.defer(),
        //Simulando latencia de rede
        delay = _.random(200, 3000);

        $timeout(function() {
          $log.log('Request ' + config.url , ' Delayed: ' + delay , config);
          deferred.resolve(config);
        }, delay);

        return deferred.promise;
        //return config;
      },
      'response': function(response) {
        var deferred = $q.defer(),
        delay = _.random(200, 3000);
        if (response.config.url.indexOf('views/') === 0) {
          return response;
        }

        $timeout(function() {
          $log.log('Response ' + response.config.url , ' Delayed: ' + delay , response);
          deferred.resolve(response);
        }, delay);

        return deferred.promise;
      }

    };
  });
});