I wrote a trigger to prevent the deletion of a record. And also I'm writing test class.

public class ClassA
    public static void preventDelete(List<Person__c> pers) { 
            for(Person__c per: pers) {
                if(per.hasJob__c == true) {
                    rra.addError('You cannot delete the record.');
                }
            }       
    }
}

On trigger:

trigger PersonTrigger on Person__c (before delete) {
        if(trigger.isDelete) {
            if (trigger.isBefore){
                ClassA.preventDelete(trigger.old);
            }
        }
}

But I'm thinking that I can write test class for this trigger by calling the method directly e.g: ClassA.preventDelete(myList); or by creating records on test class then check if it was successfully deleted or not. Then what is the difference between the two and which one is better?

Example 1:

 @isTest
    public class ClassATest {
       public static testMethod void TestPreventDelete() {   
          Person__c p1 = new Person__c(Name='Joseph', hasJob__c=true);

          List<Person__c > pers = new List<Person__c>();
          pers.add(p1);
          insert pers;               

          ClassA.preventDelete(pers); // calling the method to cover the test class
    
       }
    }

Example 2:

@isTest
    public class ClassATest {
       public static testMethod void TestPreventDelete() {   
          Person__c p1 = new Person__c(Name='Joseph', hasJob__c=true);
          insert p1;
     
          Database.DeleteResult result = Database.delete(p1, false);
          System.assert(!result.isSuccess());

       }
    }

I wrote a trigger to prevent the deletion of a record. And also I'm writing test class.

public class ClassA
    public static void preventDelete(List<Person__c> pers) { 
            for(Person__c per: pers) {
                if(per.hasJob__c == true) {
                    rra.addError('You cannot delete the record.');
                }
            }       
    }
}

On trigger:

trigger PersonTrigger on Person__c (before delete) {
        if(trigger.isDelete) {
            if (trigger.isBefore){
                ClassA.preventDelete(trigger.old);
            }
        }
}

But I'm thinking that I can write test class for this trigger by calling the method directly e.g: ClassA.preventDelete(myList); or by creating records on test class then check if it was successfully deleted or not. Then what is the difference between the two and which one is better?

Example 1:

 @isTest
    public class ClassATest {
       public static testMethod void TestPreventDelete() {   
          Person__c p1 = new Person__c(Name='Joseph', hasJob__c=true);

          List<Person__c > pers = new List<Person__c>();
          pers.add(p1);
          insert pers;               

          ClassA.preventDelete(pers); // test class by calling the method of a class 
    
       }
    }

Example 2:

@isTest
    public class ClassATest {
       public static testMethod void TestPreventDelete() {   
          Person__c p1 = new Person__c(Name='Joseph', hasJob__c=true);
          insert p1;
     
          // test class by using dml statement
          Database.DeleteResult result = Database.delete(p1, false);
          System.assert(!result.isSuccess());

       }
    }