title: The problem with NUnit and app.config
body: <p>When i run a simple test on connection to DB check i receive an error in NUnit: </p>
  
  <pre><code>[Test]
  public void TestConn()
  {
      string  connectionString = ConfigurationManager.ConnectionStrings["FertigungRead"].ConnectionString;
      SqlConnection connection = new SqlConnection(connectionString);
      connection.Open();
      Assert.AreEqual(ConnectionState.Open, connection.State);
      connection.Close();
   }
  </code></pre>
  
  <blockquote>
    <p>System.NullReferenceException : Object reference not set to an instance of an object.</p>
  </blockquote>
  
  <p>on line : </p>
  
  <pre><code>connectionString = ConfigurationManager.ConnectionStrings["FertigungRead"].ConnectionString;
  </code></pre>
  
  <p>Can i use ConfigurationManager in tests?</p>