Question

In my C# class project, I have a helper class which has the following property

public class Helper
{
    public string ConnectionString
    {
        get
        {
            return ConfigurationManager.ConnectionStrings["MyConnectionString"].ConnectionString;
        }
    }
}

My following test fails when I call the Helper class from NUNIT project with error message: Failure: System.NullReferenceException : Object reference not set to an instance of an object.

    [Test]
    public void connection_string_exists()
    {
        string connection = new Helper().ConnectionString;
        Assert.NotNull(connection);
    }

If I run the line of code new Helper().ConnectionString from a asp.net project then it works. Why does the Test fail?

Please let me know.

Answer 1

I suspect your Nunit tests are part of a different project and when you run the tests, ConfigurationManager looks at the config file of your test project and does not find “MyConnectionString”