I am trying to cover the following in my test class.

 @RemoteAction
 global static Tfunc InsertOrg(String Name,String AddressLine1,String AddressLine2,String AddressLine3,String AddressLine4,String City,String Country,String CountryName,String AliasName,String PostalCode,String StateOrProvince,String BusinessID,String RowID,String WebsiteURL){
 TOrg__c oOrganisation = new TOrg__c();
 oOrganisation.Name = Name;
 oOrganisation.Address_1__c = AddressLine1;
 oOrganisation.Address_2__c = AddressLine2;
 oOrganisation.Address_3__c = AddressLine3; 
 oOrganisation.Address_4__c = AddressLine4;
 oOrganisation.City_Name__c = City;
 oOrganisation.Country__c = Country;
 oOrganisation.Country_Name__c = CountryName;
 oOrganisation.Postal_Code__c = PostalCode;
 oOrganisation.State_Province__c = StateOrProvince;
 oOrganisation.Organization_Business_ID__c = BusinessID;
 oOrganisation.Org_Row_ID__c = RowID;
 oOrganisation.Web_Site__c = WebsiteURL;

 Upsert oOrganisation Organization_Business_ID__c;
 return oOrganisation;

 } 

Organization_Business_ID__c is an external id field . how can i get rid of the error : System.SecurityException: ViewAllData or ViewAllRecords required to access external id fields which do not have a unique index