Write tests for an angular REST app

I'm a beginner and trying to learn how to write test for a REST Angular app. I've been clueless so far. Say I have this very simple app module:

var app = angular.module('myApp', []);

app.constant('config', {
   CLIENT_ID:'123',
   CLIENT_SECRET:'123'
});

app.service('searchService',  ['$http','config', function($http,config){
    var baseURL;
    var buildBaseURL=function(client_id,client_secret){
        return "http://ift.tt/1Js2nkC"+
          "?client_id="+client_id+
          "&client_secret="+client_secret+
          "&query=";    
    }
    baseURL=buildBaseURL(config.CLIENT_ID,config.CLIENT_SECRET);
    return  {
        search: function(query){
            return  $http.get(baseURL+query);
        }
    };
}]);

app.controller('mainCtrl', ['$scope','searchService',function($scope, searchService) {
  searchService.search($scope.searchWords).success(function(data) {
        $scope.responseData=data;
  });   
}]);

It works on the browser. Now I tried to test it using karma, mocha & chai. Say I want to write a test case to test the success path of the request. How should I write that? Here is what I'm trying sofar:

describe('',function(){
    var $httpBackend = null;
    var locationService = null;

    beforeEach(function(){
        module('myApp');
        inject(function(_$httpBackend_,_locationService_){
            $httpBackend    =   _$httpBackend_;
            locationService =   _locationService_;
        });
    });

    it('test case 1',function(){
        var searchWord = 'car';
        $httpBackend.expectGET(searchWord);
        var result;
        locationService.search(searchWord).success(function(data) {
            result=data.response.venues;
        });
        console.log(result); //undefined
        $httpBackend.flush();
    });

});

All it returned is just:

"Unexpected request: GET http://ift.tt/1Js2nkC .... etc
Expected GET car
    $httpBackend@http://ift.tt/1GsHaZs
    sendReq@http://ift.tt/1Js2pJl
    $http/serverRequest@http://ift.tt/1GsHdo4
    qFactory/defer/deferred.promise.then/wrappedCallback@http://ajax.googleapis.com/ajax/libs/angularjs/1.2.16/angular.js:11319:31
... etc
Firefox 37.0.0 (Ubuntu): Executed 1 of 1 (1 FAILED) ERROR (0.034 secs / 0.004 secs)