controller.js

myapp.controller('myController', ['myService', function (myService) {
  $scope.autofillSearch; //Input field in HTML
  $scope.findAutofill = function () {
    myService.autofill($scope.autofillSearch)
      .success(function (data) {
        window.console.log('Yay! ' + data);
      })
      .error(function () {
        window.console.log('BOOO!');
      });
  }
}]);

controllerSpecs.js

describe('MyController', function() {
    var myServiceBackend,
        subject;
    
    beforeEach(function() {
        module('myApp');
        inject(function(_myServiceBackend_, $rootScope, $controller) {
            subject = $rootScope;
            myServiceBackend = _myServiceBackend_;
            
            spyOn(window.console, 'log');
            
            $controller('MyController', {$scope: $rootScope});
        });
    });
    it('can setup responses from the other service', function() {
        myServiceBackend.setupAutofill({some: 'thing'})
            .toReturn('the data!');
        
        subject.findAutofill();
        myServiceBackend.flush();
        
        expect(window.console.log).toHaveBeenCalledWith('Yay! the data!');
    });
});

myService.js

Myapp.service('myService', function($http) {
    return {
        autofill: function(lookup) {
            return $http.post('/autofill/fetch', lookup);
        }
    }
});

testStubs.js

Myapp.service('myServiceBackend', function($httpBackend) {
    var stubPromise = function(promise) {
        toReturn: function(data) {
            promise.respond(data);
        },
        toFail: function(data) {
            promise.respond(500, data);
        },
        flush: $httpBackend.flush
    };
    
    return {
        setupAutofill: function(request) {
            return stubPromise($httpBackend.expectPOST('/autofill/fetch', request));
        }
    }
});