Can anyone help me with the Test class for the batch class(to delete records which are 180 days old) I have written, I'm getting 100% code coverage in sandbox but when I'm deploying the code in production and validating using "run specified test - giving the name of my test class"  I'm getting Error as "Your Code coverage is 71%, you need at least 75% coverage to complete this deployment" 

Here is my batch class and test class:

global class DeleteOpportunityProductSnapshotBatch implements Database.Batchable<sObject>, Schedulable    
{
    global Database.QueryLocator start(Database.BatchableContext BC)
    {
        return Database.getQueryLocator([SELECT Id FROM OpportunityLineItem_Snapshot__c WHERE CreatedDate != LAST_N_Days:180]);
    }
    global void execute(Database.BatchableContext BC, List<SObject> records)
    {
    delete records;
    }
    global void finish(Database.BatchableContext BC) { }
    global void execute(SchedulableContext ctx) 
    {
        Database.executeBatch(this);
    }
}

Test Class:
@isTest
public class DeleteOppProductSnapshotBatch_Test 
{
    public static testMethod void testMethod1()
    {
        OpportunityLineItem_Snapshot__c Ols = new OpportunityLineItem_Snapshot__c();
        Ols.Name = 'Test';
        Ols.CreatedDate = Date.today().addDays(-180);
        insert Ols;
        
        Test.startTest();
        DeleteOpportunityProductSnapshotBatch Dop = new DeleteOpportunityProductSnapshotBatch();
        id batchprocessid = Database.executeBatch(Dop);
        
        DeleteOpportunityProductSnapshotBatch sh1 = new DeleteOpportunityProductSnapshotBatch();
        String sch = '0 0 2 * * ?';
        system.schedule('Test Territory Check', sch, sh1);

        Test.stopTest();
        
        System.assert(batchprocessid != null);
    }