Mocking an NHibernate ISession with Moq

Question

Hello, I am starting a new project with NHibernate, ASP.NET MVC 2.0 and StructureMap and using NUnit and Moq for testing. For each of my controllers I have a single public constructor into which an ISession is being injected. The application itself works just fine, but in terms of unit testing I essentially have to mock an ISession in order to test the controllers.

When I attempt to Mock the ISession with MOQ i get the following error message:

Only property accesses are supported in intermediate invocations

It appears that my problem is expecting List of users from the framework CreateQuery method but after googling the issue I am now clearer.

I have two questions:

1) Is this the WRONG way to mock dependency injection of an ISession

2) Is there a way to modify the code so that it can successfully return my list

            [Test]
            public void DummyTest()
            {

                var mock = new Mock<ISession>();
                var loc = new Mock<User>();
                loc.SetupGet(x => x.ID).Returns(2);
                loc.SetupGet(x => x.FirstName).Returns("John");
                loc.SetupGet(x => x.LastName).Returns("Peterson");

                var lst = new List<User> {loc.Object};
                mock.Setup(framework => framework.CreateQuery("from User").List<User>()).Returns(lst);

                var controller = new UsersController(mock.Object);
                var result = controller.Index() as ViewResult;
               Assert.IsNotNull(result.ViewData);
            }

Please note, I am pretty sure I could just create a hard-coded list of users (rather than mocking an individual User and adding it to a list) but figured I'd leave the code as I have it right now.

Also, the Index action of this particular controller essentially executes the CreateQuery call mimicked above to return all users in the database. This is a contrived example - don't read anything into the details.

Thanks in advance for your help

Edit: In reply to the below comment, I am adding the stacktrace for the error. Also, all properties on the User class are virtual.

TestCase 'Beta.Tests.Unit.Controllers.UserControllerTest.Details_InValidIndex_ReturnsNotFoundView' failed: System.NotSupportedException : Only property accesses are supported in intermediate invocations on a setup. Unsupported expression framework.CreateQuery("from User"). at Moq.Mock.AutoMockPropertiesVisitor.VisitMethodCall(MethodCallExpression m) at Moq.ExpressionVisitor.Visit(Expression exp) at Moq.Mock.AutoMockPropertiesVisitor.VisitMethodCall(MethodCallExpression m) at Moq.ExpressionVisitor.Visit(Expression exp) at Moq.Mock.AutoMockPropertiesVisitor.SetupMocks(Expression expression) at Moq.Mock.GetInterceptor(LambdaExpression lambda, Mock mock) at Moq.Mock.<>c__DisplayClass122.<Setup>b__11() at Moq.PexProtector.Invoke[T](Func1 function) at Moq.Mock.Setup1 expression) at Moq.Mock1.Setup%5BTResult%5D%28Expression`1 expression">T1,TResult Controllers\UserControllerTest.cs(29,0): at Beta.Tests.Unit.Controllers.UserControllerTest.Details_InValidIndex_ReturnsNotFoundView()

Answer 1

Rather than mocking the Session, one might consider setting up a different Configuration for unit-tests. This unit-testing Configuration uses a fast, in-process database like SQLite or Firebird. In the fixture setup, you create a new test database completely from scratch, run the scripts to set up the tables, and create a set of initial records. In the per-test setup, you open a transaction and in the post-test teardown, you rollback the transaction to restore the database to its previous state. In a sense, you are not mocking the Session, because that gets tricky, but you are mocking the actual database.

Answer 2

Below is the solution I came up with which seems to work perfectly. Again, I am not testing NHibernate and I am not testing the database - I simply want to test the controllers which depend on NHibernate. The issue with the initial solution appears to be the fact that I was calling a Method as well as reading the List member of the session in the MOQ setup call. I broke up these calls by breaking the solution into a QueryMock and a Session Mock (create query returns an IQuery object). A transaction mock was also necessary as it is a dependency (in my case) of the session...

        [Test]
        public void DummyTest()
        {
            var userList = new List<User>() { new User() { ID = 2, FirstName = "John", LastName = "Peterson" } };
            var sessionMock = new Mock<ISession>();
            var queryMock = new Mock<IQuery>();
            var transactionMock = new Mock<ITransaction>();

            sessionMock.SetupGet(x => x.Transaction).Returns(transactionMock.Object);
            sessionMock.Setup(session => session.CreateQuery("from User")).Returns(queryMock.Object);
            queryMock.Setup(x => x.List<User>()).Returns(userList);

            var controller = new UsersController(sessionMock.Object);
            var result = controller.Index() as ViewResult;
            Assert.IsNotNull(result.ViewData);
        }

Answer 3

Hey JP, were u able to mock the session. I am trying something similar but I get the type exception on Session Factory for not able to cast it to SessionFactoryImplementor.

Answer 4

There is a very good article from Ayende, how you can test NHibernate:

http://ayende.com/Blog/archive/2009/04/28/nhibernate-unit-testing.aspx

cheers