ExecuteBatch() method is not invoked when testing Batch Test Class

HI , when testing batch class , may test doesn;t seem to be invoking the executeBatch() method even though it does have a valid list of opportunities for the scope. I traced the code flow in debug log to where it finished the start method in creating the QueryLocator and saw that it did contain a list of opportunities but it did not reach the executeBatch method but skipped ahead to the finish method. So now I am  only able to cover 53%.  I wonder why the Query Locator skipped to Finish upon return? Doesn;t it flow into executeBatch if the object for scope is not empty?  Here is my class code for batch: 

global class BatchGeneratePickTicketsByQuery implements Database.Batchable<sObject>
{
    global String Query;
    global Database.QueryLocator start(Database.BatchableContext BC)
    {
        String DefaultQuery = 
            ' Select Id, AccountId, Account.Name, RecordTypeId, RecordType.Name, Name, ' + 
            ' StageName, Amount, CreatedDate, CreatedById, CreatedBy.Name, HasOpportunityLineItem, LastModifiedDate, ' +
            ' LastModifiedById, LastModifiedBy.Name, TotalOpportunityQuantity, Total_Pick_Quantity__c, ' +
            ' Total_Pick_Tickets__c, Inventory_Items__c, Non_inventory_Items__c, Error_Log__c, ' +
            ' (Select Id, Name From Pick_Tickets__r) ' + 
            ' FROM Opportunity Where CreatedDate > 2012-07-01T00:00:00.000Z ' +
            ' And RecordType.Name = \'Orders\' ' + 
            ' And Amount > 0 ' + 
            ' And (StageName = \'Order Confirmed\' OR StageName like \'%Partially%\') ' + 
            ' And (NOT StageName like \'%Cancelled%\') ' + 
            ' And Id Not In (Select Opportunity__c From Sales_Order__c) ';
        if(Query == null) {
           Query = DefaultQuery; 
        }
        else {
            system.debug('<<QUERY>> '+Query);
            if(!Query.toLowerCase().contains('from opportunity')) { Query = null; } 
        }
        system.debug('QUERY >> '+Query);
        return Database.getQueryLocator(Query);
    }
    global void execute(Database.BatchableContext BC, List<sObject> scope)
    {
        for(sObject s : scope)
        {
            Opportunity o = (Opportunity)s;
            OrderEntryStatus.QueueGeneratePickTicket(o.Id);
        }
    }
    global void finish(Database.BatchableContext BC)
    {
        system.debug(BC);
    }
}

 2) Here is the Test Class for the batch class:

@isTest
public class BatchGeneratePickTicketsByQuery_Test {
	static testmethod void test() {
String Query =
      ' Select Id, AccountId, Account.Name, RecordTypeId, RecordType.Name, Name, ' + 
          ' StageName, Amount, CreatedDate, CreatedById, CreatedBy.Name, HasOpportunityLineItem, LastModifiedDate, ' +
          ' LastModifiedById, LastModifiedBy.Name, TotalOpportunityQuantity, Total_Pick_Quantity__c, Company__c,Shipping_Weight__c, ' +
          ' Total_Pick_Tickets__c, Inventory_Items__c, Non_inventory_Items__c, Error_Log__c ' + 
          ' FROM Opportunity Where CreatedDate > 2012-07-01T00:00:00.000Z ' +
          ' And RecordType.Name = \'Orders\' ' + 
      ' And Amount >= 0 ' + 
      ' And (Total_Pick_Tickets__c > 0 OR Pick_Ticket_Not_Fulfillable__c = true) ' + 
      ' And StageName != \'Order Cancelled\' ' + 
      ' And StageName != \'Order Invoiced\' ' + 
      ' And (Not StageName like \'%Fulfilled%\') ' + 
      ' And (StageName like \'%Partially%\' OR StageName = \'Order Confirmed\' OR Pick_Ticket_Not_Fulfillable__c = true) ' + 
      ' And Id Not In (Select Opportunity__c From Sales_Order__c)';
		Test.startTest();	
        BatchGeneratePickTicketsByQuery bgptbq = new BatchGeneratePickTicketsByQuery();
        bgptbq.Query= null;
        ID batchprocessid = Database.executeBatch(bgptbq);
		Test.stopTest();
    }
}