public void Sys_foreign_keys_null()
 {
     foreign_keys f = new foreign_keys();
     List<foreign_keys> fl = f.ToList;
     Assert.AreEqual<List<foreign_keys>>(fl, null);
 }
 public void Sys_foreign_keys()
 {
     foreign_keys f = new foreign_keys(connStr);
     List<foreign_keys> fl = f.ToList;
     Assert.AreNotEqual<List<foreign_keys>>(fl, null);
 }