This is my class please help me out to write test class
public class AccountTriggerHandler implements ITriggerHandler
{
    public static Boolean TriggerDisabled = false;

    /*
        Checks to see if the trigger has been disabled. For example, you could check a custom setting here.
        In this example, a static property is used to disable the trigger.
        In a unit test, you could use AccountTriggerHandler.TriggerDisabled = true to completely disable the trigger.
    */
    public Boolean IsDisabled()
    {
        return TriggerDisabled;
    }

    public void BeforeInsert(List<SObject> newItems) 
    {
        // Cast the List<Sobject> to List<Account>
        AccountNameCheck((List<Account>)newitems);
    }

    public void BeforeUpdate(Map<Id, SObject> newItems, Map<Id, SObject> oldItems) 
    {
        // Cast the Map<Id, Sobject> to List<Account>
        AccountNameCheck((List<Account>)newitems.values());
    }

    public void BeforeDelete(Map<Id, SObject> oldItems) {}

    public void AfterInsert(Map<Id, SObject> newItems) {}

    public void AfterUpdate(Map<Id, SObject> newItems, Map<Id, SObject> oldItems) {}

    public void AfterDelete(Map<Id, SObject> oldItems) {}

    public void AfterUndelete(Map<Id, SObject> oldItems) {}

    /*
        Check the accounts to make sure their name does not contain the text "test".
        If any do, reject them.
    */
    private void AccountNameCheck(List<Account> accountList)
    {
        // Reject any Accounts which have the word "Test" in the name
        for (Account acc : accountList)
        {
            //if (acc.Name.contains('test'))
                //acc.Name.addError('You may not use the word "test" in the account name');
        }
    }
}