Newbie questiion on Isolator and LinqToSql testing

Hi Alex,

If you want to test the linq expression you probably want to fake DataContext.GetTable or extract the the data base access to a separate class which seems like a better idea :)
Here's an example:

public class DataAccsess
{
    public List<DbAccountCredential> GetTable()
    {
        var db = new DataContext(DataBaseUtil.ConnectionString);
        return db.GetTable<DbAccountCredential>().ToList();
    }
}

public long GetUserIdByUsernameAndPassword(string username, string password)
{
    DataAccsess dataAccsess = new DataAccsess();
    var table = dataAccsess.GetTable();

    var query =
        from credentials in table
        where credentials.UserName == username && credentials.PassWord == password
        select (new { credentials.AccountId });

    return query.SingleOrDefault().AccountId;
}        

[Test]
public void Test()
{
    var fakeList = new List<DbAccountCredential>();
    
    var fake = Isolate.Fake.Instance<DataAccsess>();
    Isolate.WhenCalled(() => fake.GetTable()).WillReturn(fakeList);
    Isolate.Swap.NextInstance<DataAccsess>().With(fake);

    var foo = new Foo();
    long actual = foo.GetUserIdByUsernameAndPassword("user", "password");
    //...
}

Hope that I guessed right about what you want to test :D
Please let me know if it helps.

Thank you for the help :D got me into what i think was the best way of doing it... Didn't want the GetTable() to return a List.

public class DataAccsess 
{ 
    public Table<DbAccountCredential> GetTable() 
    { 
        var db = new DataContext(DataBaseUtil.ConnectionString); 
        return db.GetTable<DbAccountCredential>(); 
    } 
}
......
public long GetUserIdByUsernameAndPassword(string username, string password)
{ 
    DataAccsess dataAccsess = new DataAccsess(); 
    var table = dataAccsess.GetTable(); 

    var query = 
        from credentials in table.ToList();
        where credentials.UserName == username && credentials.PassWord == password 
        select (new { credentials.AccountId }); 

    return query.SingleOrDefault().AccountId; 
} 
...........
[Test,Isolated]
public void GetUserIdByUsernameAndPassword_ValidUsernameAndPassword_ReturnsUserIdAsLong()
{
    List<DbAccountCredential> fakeList = GetFakeAccountCredentialsList();
    long validUserIdToReturn = 1;
    string username = "admin";
    string password = "admin";
    var fakeAccess = Isolate.Fake.Instance<DataBaseUtil>();
    var foo = new LoginModel();

    Isolate.WhenCalled(() => fakeAccess.GetAccountCredentialsTable().ToList()).WillReturn(fakeList);
    Isolate.Swap.NextInstance<DataBaseUtil>().With(fakeAccess);
            
    long actual = foo.GetUserIdByUsernameAndPassword(username, password);

    Assert.AreEqual(actual, validUserIdToReturn);
}

"Feels" like the correct way of doing it and it makes the GetTable() method more reusable.