TestingConnect=
  (DESCRIPTION =
    (ADDRESS = (PROTOCOL = TCP)(HOST = TestHostName.us.local)(PORT = 1523))
    (CONNECT_DATA =
      (SERVER = DEDICATED)
      (SERVICE_NAME = TEST)
    )
  )

Oracle.DataAccess.Client.OracleConnection connection = new Oracle.DataAccess.Client.OracleConnection();

connection.ConnectionString = "Data Source=TestHostName.us.local;Persist Security Info=True;" + "User ID=tesName;Password=test";

connection.Open() //Throwing ERR!!!

private static string GetConnectionString()
    {
        return "Data Source=(DESCRIPTION=(ADDRESS_LIST=(ADDRESS=(PROTOCOL=TCP)(HOST=TestHostName.us.local)(PORT=1523) ) )" +
               "(CONNECT_DATA=(SERVER=DEDICATED)(SERVICE_NAME=CCDB)));User id=UserName; Password=Password; enlist=false; pooling=false;";
    }

connection.ConnectionString = "Data Source=TestingConnect;Persist Security Info=True;" + "User ID=tesName;Password=test";

connection.ConnectionString = "Data Source=(DESCRIPTION = " +
    "(ADDRESS = (PROTOCOL = TCP)(HOST = TestHostName.us.local)(PORT = 1523))" +
    "(CONNECT_DATA =" +
    "(SERVER = DEDICATED)" +
    "(SERVICE_NAME = TEST))" +
    ");Persist Security Info=True;User ID=tesName;Password=test";