Hi,

I'm trying to create a bunch of MS visual studio unit tests for my n-tiered web app but for some reason I can't run those tests and I get the following error -

"Object reference not set to an instance of an object"

What I'm trying to do is testing of my data access layer where I use LINQ data context class to execute a certain function and return a result,however during the debugging process I found out that all the tests fail as soon as they get to the LINQ data context class and it has something to do with the connection string but I cant figure out what is the problem.

The debugging of tests fails here(the second line):

public EICDataClassesDataContext() :
    base(global::System.Configuration.ConfigurationManager.ConnectionStrings["EICDatabaseConnectionString"].ConnectionString, mappingSource)
    {
        OnCreated();
    }

And my test is as follows:

TestMethod()]
    public void OnGetCustomerIDTest()
    {
        FrontLineStaffDataAccess target = new FrontLineStaffDataAccess(); // TODO: Initialize to an appropriate value
        string regNo = "jonh"; // TODO: Initialize to an appropriate value
        int expected = 10; // TODO: Initialize to an appropriate value
        int actual;
        actual = target.OnGetCustomerID(regNo);
        Assert.AreEqual(expected, actual);
    }

The method which I call from DAL is:

 public int OnGetCustomerID(string regNo)
    {
        using (LINQDataAccess.EICDataClassesDataContext dataContext = new LINQDataAccess.EICDataClassesDataContext())
        {
            IEnumerable<LINQDataAccess.GetCustomerIDResult> sProcCustomerIDResult = dataContext.GetCustomerID(regNo);
            int customerID = sProcCustomerIDResult.First().CustomerID;

            return customerID;
        }
    }

So basically everything fails after it reaches the 1st line of DA layer method and when it tries to instantiate the LINQ data access class...

I've spent around 10 hours trying to troubleshoot the problem but no result...I would really appreciate any help!

UPDATE: Finally I've fixed this!!!!:) I dont know why but for some reasons in the app.config file the connection to my database was as follows:

AttachDbFilename=|DataDirectory|\EICDatabase.MDF

So what I did is I just changed the path and instead of |DataDirectory| I put the actual path where my MDF file sits,i.e

C:\Users\1\Documents\Visual Studio 2008\Projects\EICWebSystem\EICWebSystem\App_Data\EICDatabase.mdf

After I had done that it worked out!But still it's a bit not clear what was the problem...probably incorrect path to the database?My web.config of ASP.NET project contains the |DataDirectory|\EICDatabase.MDF path though..