My trigger works and my Test Class have 85% coverage but I would like to know how to get a littl emore coverage.

Not so much for the coverage itself but for the knowlege of how to do this in the future.

My trigger runs for inserts and updates.

My test class covers the insert but not the update and i am not at all; sure how to do both.

Here is the trigger:

trigger createOqNew on Opportunity (after insert, after update) 

//trigger
{ 
   
    // try
    try{
           
        Id recordTypeId =
        Schema.SObjectType.Opportunity.getRecordTypeInfosByDeveloperName().get('CDARS_ICS_Prospect').getRecordTypeId();
        
        List <Open_Quarter__c> createOpenQuarter = new List <Open_Quarter__c>();
        List <Open_Quarter__c> deleteOpenQuarter = new List <Open_Quarter__c>();
        Set <Id> processedOpportunities = new Set <Id>();
        
        // for loop 1
        for (Opportunity opportunityList : Trigger.new) {   
            
            // if loop 1
            if (opportunityList.RecordTypeId == recordTypeId) {
                
                // if loop 2
                if (Trigger.isInsert 
                    || (Trigger.isUpdate && opportunityList.Estimated_Start_Quarter__c != Trigger.oldMap.get(opportunityList.Id).Estimated_Start_Quarter__c)
                    || (Trigger.isUpdate && opportunityList.Estimated_Finish_Quarter__c != Trigger.oldMap.get(opportunityList.Id).Estimated_Finish_Quarter__c)){
                                          
                    Decimal year = opportunityList.Start_Year__c;
                    Decimal quarter = opportunityList.Start_Quarter__c;
                    Decimal span = opportunityList.Quarters_Spanned_op__c;
                    processedOpportunities.add(OpportunityList.Id);
                        
                    //for loop 2
                    for (Integer counter = 0; counter < span; counter++)
                    {
                        Open_Quarter__c oq           		= new Open_Quarter__C();
                        oq.Amount_Per_Quarter_oq__c  		= opportunityList.Amount_per_Quarter_op__c;
                        oq.Estimated_Finish_Quarter_OQ__c   = opportunityList.Estimated_Finish_Quarter__c;
                        oq.Estimated_Start_Quarter_OQ__c	= opportunityList.Estimated_Start_Quarter__c;
                        oq.Name                      		= year+'-'+'Q'+quarter;
                        oq.Opportunity_Name_oq__c    		= opportunityList.Id;
                        
                        createOpenQuarter.add(oq);
                        quarter++;
                        
                        // if loop 3
                        if (quarter > 4) {
                            quarter = 1;
                            year++;
                        } //end if loop 3                       
                    } //end for loop 2      
                } //end if loop 2
            } //end if loop 1
        } //end for loop 1
        deleteOpenQuarter.addAll ([SELECT Id, Name FROM Open_Quarter__c WHERE Opportunity_Name_oq__c IN :processedOpportunities]);
        
        // if loop 4
        if (deleteOpenQuarter.isEmpty()==false){
            Database.delete (deleteOpenQuarter,false);
        } // end if loop 4
        
        // if loop 5
        if(createOpenQuarter.isEmpty()==false){
            Database.insert (createOpenQuarter,false);
        } // end if loop 5
    } // end try
    
    //catch
    catch (Exception e){
        //e.getMessage()
            //e.getLineNumber()
            throw e;
    } // end catch
} // end trigger

And here is the test class:

@isTest
public class TestCreateOqNew {
    
    @isTest static void testForCreateOQ() {
        
        Account acct = new Account(Name='Steve Test Account',
                                   recordTypeId='01241000001I8KBAA0',
                                   Service_Membership__c='Non-Member',
                                   Type='Bank');
        insert acct;
        
        Opportunity opp = new Opportunity(name=acct.Name + 'Opportunity',
                                          recordTypeId='01241000001USq9AAG',
                                          StageName='Prospecting',
                                          CloseDate=System.today().addMonths(6),
                                          Estimated_Finish_Quarter__c=System.today().addMonths(6),
                                          Estimated_Start_Quarter__c=System.today(),
                                          AccountId=acct.Id,
                                          Objective__c='Onboard - New',
                                          Amount=987654321,
                                          LeadSource='Webinar',
                                          Product_Type__c='CDARS Reciprocal');
        
        
        Test.startTest();
        insert opp;
        List<Open_Quarter__c> quarters = [SELECT Id, Name, Amount_Per_Quarter_oq__c, Estimated_Finish_Quarter_OQ__c, Estimated_Start_Quarter_OQ__c  , Opportunity_Name_oq__c FROM Open_Quarter__c ORDER BY Name];
        Test.stopTest();
        
        
        System.assertEquals(3, quarters.size());
        System.assertEquals('2020-Q2', quarters[0].name);            
        
    }
}

This is the main bit that is not covered:

|| (Trigger.isUpdate && opportunityList.Estimated_Start_Quarter__c != Trigger.oldMap.get(opportunityList.Id).Estimated_Start_Quarter__c)
                    || (Trigger.isUpdate && opportunityList.Estimated_Finish_Quarter__c != Trigger.oldMap.get(opportunityList.Id).Estimated_Finish_Quarter__c)){

(the "OR" parts).

Any tips on how to cover the update as well as the insert?

Thanks much,
Steve​​​​​​​​​​​​​​