public string Save(Test aTest)
 {
     if (aTest.TestName == String.Empty || aTest.Fee == String.Empty)
     {
         return("Please Enter Test Name and Fee");
     }
     else
     {
         if (Convert.ToDouble(aTest.Fee) < 0)
         {
             return("Fee Can't Be Negative!");
         }
         else
         {
             if (aTestGateway.DoesTestNameExist(aTest))
             {
                 return("Test Name Exists Already!");
             }
             else
             {
                 return(aTestGateway.Save(aTest));
             }
         }
     }
 }