1. i created the Trigger. Trigger use is once insert the records in Broker object automatically convert the records in contact object. once update the Broker object then Contact also updated.once delete the Broker object Contact also deleted.Trigger working Properly. but i need the Test Class for this Trigger. Test class code coverage is 13% how can i reach 75%. please help me .................

Trigger:

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 if(Trigger.isInsert){
        List<Contact> con = new List<Contact>();
        List<Broker__c> bro = new List<Broker__c>();
        List<Broker__c> UBList = new List<Broker__c>();
        List<ID> BIDs = new List<ID> {};
        for(Broker__c br:Trigger.New){
            bro.add(br);
            BIDs.add(br.id);
        }
      
        for(Broker__c b: bro) {
            Contact c = new Contact();
            c.LastName = b.Name;
            c.Title=b.Title__c;
            c.Contact_type__c=b.Broker_Type__c;
            c.Appointed_w_SeeChange__c=b.Appointed_with_SeeChange__c;
            c.RecordTypeId='012Z00000004JZS';
            c.Broker__c = b.Id;
           
            con.add(c);
        }
        insert con;
        
       Map<ID,Broker__c> UB = new Map<ID,Broker__c> {};
         for(Broker__c bc: [select id, contact_id__c, Agency__r.OwnerId from Broker__c where Id in : BIDs]) {
                UB.put(bc.Id,bc);
        }
        
        for(Contact c: con) {
            if(UB.containsKey(c.Broker__c)) {
                Broker__c UBCon = UB.get(c.Broker__c);
                UBCon.Contact_ID__c = c.Id;
                UBCon.Owner__c = UBCon.Agency__r.OwnerId;
                UBList.add(UBCon);
            }
        }
        update UBList;

    }    
    //Update Contact        
    if(Trigger.isUpdate){
        Map<ID,Broker__c> UB1 = new Map<ID,Broker__c> {};
        List<Contact> UpConList = new List<Contact> {};
        Set<ID> UBIDs = new Set<ID> {};
        for(Broker__c b: Trigger.new) {
            UB1.put(b.id,b);            
            UBIDs.add(b.id);
        }
        
        System.debug('Broker Map:'+UB1);
        for(Contact c: [select id, broker__c from contact where broker__c in :UBIDs]){
            Broker__c b = new Broker__c();
            if(UB1.containsKey(c.broker__c)) {
                b = UB1.get(c.broker__c);
                System.debug('Map get:'+b);
                c.LastName = b.Name;
                c.Title=b.Title__c;
                c.Contact_type__c=b.Broker_Type__c;
                c.Appointed_w_SeeChange__c=b.Appointed_with_SeeChange__c;
                c.Appointed_since__c=b.Appointed_Since__c;
                c.RecordTypeId='012Z00000004JZS';
                c.Broker__c = b.Id;
                UpConList.add(c);
            }
        }
        System.debug('UpConList:'+UpConList);
        update UpConList;
     }
     
    //Delete Contact
    if(Trigger.isDelete){
        List<ID> DBList = new List<ID>();
        List<Contact> DelConList = new List<Contact>();
        for(Broker__c b:Trigger.old) {
            DBList.add(b.id);
            System.debug('b value:'+b+'b.id:'+b.id);
        }  
        
        System.debug('DBList:'+DBList);
        DelConList = [select id from contact where Broker__c in :DBList];
        if(DelConList.size() >0) {
           delete DelConList;
        }
    }
 

i write the test class for Trigger. but showing this error Exception:System.ListException: Duplicate id in list:

how can solve this problem........