How to cover undelete method in test class for trigger

Question

How do I cover the after undelete process in test class for the trigger. The lines which are not covering is below,

public void executeOnUnDeleteAccount(list<Account> accountNewList) {
    set<ID> parentAccountIdSet = new set<ID>();
    for (Account account : accountNewList) {
        if(account.ParentId != null) {
            // set parent Accounts
            parentAccountIdSet.add(account.ParentId);               
        }
    }

    if(!parentAccountIdSet.IsEmpty() && parentAccountIdSet != null){
        // fetch all child accounts
        fetchAllChildAccounts(parentAccountIdSet);
    }
}

  **Test class **


 @isTest
  public class Account_AggregateMRROfChildAccountsTest {
    public static testMethod void insertAccount() {
      Account parentAccount  = new Account();
      parentAccount.Name = 'Test parent Account';
      insert parentAccount;

    Account childAccount  = new Account();
    childAccount.Name = 'Test child Account';
    childAccount.ParentId = parentAccount.Id;
    insert childAccount;

    Opportunity opportunity = new Opportunity(AccountId = childAccount.Id,
                                              Name = 'OpprtuityNAme1', 
                                              StageName = 'Prospecting',
                                              CloseDate = Date.today());
    insert opportunity;

    //Created product line item for MMR__c field
    Id pricebookId = Test.getStandardPricebookId();
    Product2 p2 = new Product2(Name = 'Tes12 Product',
                               ProductCode = 'Pro-X',
                               isActive = true,
                               CanUseRevenueSchedule = true);
    insert p2;

    PricebookEntry pbe = new PricebookEntry(Pricebook2Id = pricebookId,
                                            Product2Id = p2.Id,
                                            UnitPrice = 99,
                                            isActive=true);
    insert pbe;

    OpportunityLineItem oli = new OpportunityLineItem(PriceBookEntryId = pbe.Id,
                                                      OpportunityId = opportunity.Id,
                                                      Quantity = 1,
                                                      UnitPrice = 99);
    insert oli;
}

public static testMethod void updateAccount() {
    Account parentAccount  = new Account();
    parentAccount.Name = 'Test parent Account';
    insert parentAccount;

    Account childAccount  = new Account();
    childAccount.Name = 'Test child Account';
    childAccount.ParentId = parentAccount.Id;
    insert childAccount;

    Opportunity opportunity = new Opportunity(AccountId = childAccount.Id,
                                              Name = 'OpprtuityNAme1', 
                                              StageName = 'Prospecting',
                                              CloseDate = Date.today());
    insert opportunity;

    //Created product line item for MMR__c field
    Id pricebookId = Test.getStandardPricebookId();
    Product2 p2 = new Product2(Name = 'Tes12 Product',
                               ProductCode = 'Pro-X',
                               isActive = true,
                               CanUseRevenueSchedule = true);
    insert p2;

    PricebookEntry pbe = new PricebookEntry(Pricebook2Id = pricebookId,
                                            Product2Id = p2.Id,
                                            UnitPrice = 99,
                                            isActive=true);
    insert pbe;

    OpportunityLineItem oli = new OpportunityLineItem(PriceBookEntryId = pbe.Id,
                                                      OpportunityId = opportunity.Id,
                                                      Quantity = 1,
                                                      UnitPrice = 99);
    insert oli;

    Opportunity opportunity2 = new Opportunity(AccountId = childAccount.Id,
                                              Name = 'OpprtuityNAme1', 
                                              StageName = 'Prospecting',
                                              CloseDate = Date.today());
    insert opportunity2;

    Product2 p = new Product2(Name = 'Tes12 Product',
                               ProductCode = 'Pro-X',
                               isActive = true,
                               CanUseRevenueSchedule = true);
    insert p;

    PricebookEntry pbe1 = new PricebookEntry(Pricebook2Id = pricebookId,
                                            Product2Id = p.Id,
                                            UnitPrice = 99,
                                            isActive=true);
    insert pbe1;

    OpportunityLineItem oli1 = new OpportunityLineItem(PriceBookEntryId = pbe1.Id,
                                                      OpportunityId = opportunity2.Id,
                                                      Quantity = 1,
                                                      UnitPrice = 99);
    insert oli1;
}

public static testMethod void deleteAccount() {
    Account parentAccount  = new Account();
    parentAccount.Name = 'Test parent Account';
    insert parentAccount;

    Account childAccount  = new Account();
    childAccount.Name = 'Test child Account';
    childAccount.ParentId = parentAccount.Id;
    insert childAccount;

    delete childAccount;

    Account[] savedAccts = [SELECT Id, Name FROM Account WHERE Name = 'test child KK 2' ALL ROWS]; 
    undelete savedAccts;
   }
 }

Answer 1

You can go through the Restoring Deleted Records

Deleted records can be restored using the undelete operation.

Account a = new Account(Name='Trump');
insert a;

delete a;

Account[] savedAccts = [SELECT Id, Name FROM Account WHERE Name = 'Trump' ALL ROWS]; 

undelete savedAccts;