Question

I’m facing an issue I don’t quite understand.

I’m developing an application in C#/ASP.net using the Entity Framework.
I’m trying to do some unit testing on it, and therefore I need to mock one of the object, and I can’t seem to work it out.

Here is the class I want to mock:
http://pastebin.com/pMypAM7G

This class returns a new DataSourceContainer if no one currently exists, and returns the existing one otherwise (needed it to avoid having multiple contexts)

Here is the interface (which only purpose is to allow mocking) : http://pastebin.com/LRYVdA9j

Here is the fonction I am trying to test : http://pastebin.com/naVsV3FX

And here is the test fonction : http://pastebin.com/dY4ERzSJ

When I try to do the test, I get an error on the Database class, within the getter, because there is no HttpContext (which is logical).
What I don’t get is that the getter is supposed to be mocked.

I’ve tried to look it up on the internet but I can’t figure out what I’m doing wrong, so if someone could help me out on this one, I’d be really grateful. Thanks !

Answer 1

You have not imeplemented your code properly to support unit testing – you are creating external object (Database) in your method. Also, you are not using IDatabase interface, but concrete implementation of Database

    public static User Connexion(String login, String MotDePasse)
    {
        Database bdd = new Database(); // this is inline, concrete implementation, this cannot be mocked

        User us = bdd._Context.UserSet.FirstOrDefault(u => u.login == login);
        if (us == null)
            throw new Exception("Nom d'utilisateur erroné");
        if (us.password != MotDePasse)
            throw new Exception("Mot de passe erroné");
        else
            return us;
    }

You should read at least about Dependency Injection.

This short example may help you understand problems in your code

    public static User Connexion(String login, String MotDePasse, IDatabase bdd)
    {
        User us = bdd._Context.UserSet.FirstOrDefault(u => u.login == login);
        if (us == null)
            throw new Exception("Nom d'utilisateur erroné");
        if (us.password != MotDePasse)
            throw new Exception("Mot de passe erroné");
        else
            return us;
    }

This time, Connexion is loosely bound to IDatabase interface, not to its implementation. At runtime, you would supply new Database() as its value, but at test-time, mocked implementation.