How to write test case for angular service using jasmine?

I wanted to create a unit test case for the following controller function.

$scope.login = function(){
    $scope.login.wrong = false;
    $scope.login.errorMsg = '';
    var loginPromise = $http.post('backend/login', $scope.credentials);
    $scope.login.working = true;
    loginService.loginUser(loginPromise);
    loginPromise.error(function(data, status, headers, config){
        $scope.login.wrong = true;
        $scope.login.errorMsg = data.errDesc;
            });
            loginPromise.finally(function(){
                $scope.login.working = false;
                if(loginService.isLogged && !$scope.login.wrong)
                {
                    $scope.loggedInSuccessfully = true;

                }
            });
        };

This is the service

angular.module('loginService', [])
.provider('loginService', function () {
  var userToken = localStorage.getItem('userToken'),
      errorState = 'app.error',
      loginState = 'app.login',
      logoutState = 'app.login';

  this.$get = function ($rootScope, $http, $q, $state) {
    var setHeaders = function (token) {
      if (!token) {
        delete $http.defaults.headers.common['authToken'];
        return;
      }
      $http.defaults.headers.common['authToken'] = token.toString();
    };

    var setToken = function (token) {
      if (!token) {
        localStorage.removeItem('userToken');
      } else {
        localStorage.setItem('userToken', token);
      }
      setHeaders(token);
    };

      var setOrgId = function( orgId ){
          if(!orgId){
              localStorage.removeItem('userOrgId');
          }
          else{
              localStorage.setItem('userOrgId', orgId);
          }

          setHeaderOrgId(orgId);
      };

      var setHeaderOrgId = function( orgId ){
          if(!orgId){
              delete $http.defaults.headers.common['orgId'];
              return;
          }
          $http.defaults.headers.common['orgId'] = orgId.toString();
      }

    var getLoginData = function () {
      if (userToken) {
        setHeaders(userToken);
      } else {
        wrappedService.userRole = userRoles.public;
        wrappedService.isLogged = false;
        wrappedService.doneLoading = true;
      }
    };

    var wrappedService = {
      loginHandler: function (user, status, headers, config) {
        setToken(user.authToken);
          setOrgId(user.organizationId);
        angular.extend(wrappedService.user, user);
        wrappedService.isLogged = true;
        wrappedService.userRole = userRoles[user.userType];
        localStorage.setItem("anu-user",user);
        return user;
      },
      loginUser: function (httpPromise) {
        httpPromise.success(this.loginHandler);
      },
      /**
       * Public properties
       */
      userRole: null,
      user: {},
      isLogged: null,
      pendingStateChange: null,
      doneLoading: null
    };

    getLoginData();
    managePermissions();

    return wrappedService;
  };
});

Can anyone please help me to write the test cases.I want to check following test cases - Check the variable working after the loginMe function is trigger. - Check that the loginService.loginUser() is been called when the loginMe function is trigger. - Mock a possible errorMsg from the Api to check that is been correctly displayed. - Check that Login button is enabled if an error message is displayed.