Question

Using Linq to sql and server explorer, I mapped to a loginvalidation stored proc. So I write the following code:

ClientReportingDataContext db = new ClientReportingDataContext();
var data = db.ADMIN_LoginValidation(login, password);

It throws up an exception on the following line:

public ClientReportingDataContext() : 
        base(global::System.Configuration.ConfigurationManager.ConnectionStrings["FeedsConnectionString"].ConnectionString, mappingSource)

Exception thrown:

Object reference not set to an instance of an object.

I’m calling this function from a unit test class. I cann feedsconnectionstring in web.config.

I put the web.config in the unit tests folder, and also under debug and debug/bin. Not sure what I’m missing.

Thanks in advance for any advise.

Answer 1

For a unit test,

ConnectionStrings["FeedsConnectionString"].ConnectionString

won’t be reading from your web.config file; it will be reading from the application configuration file for the test runner. Therefore, unless you’ve put FeedsConnectionString in the application configuration file for your test runner,

ConnectionStrings["FeedsConnectionString"]

is null and so

ConnectionStrings["FeedsConnectionString"].ConnectionString

is going to throw a NullReferenceException.

This is why testing and application configuration files don’t get along well.

You should consider the following:

public ClientReportingDataContext(string connectionString) :
    base(connectionString, mappingSource)

Then inject your connection string in your test.