I have an Apex class on  Custom Object Called QueueDistroHelper__c 

What I am basically doing is getting the Queue Id from a custom field(Related_Queue_Id__c) on the Custom object 

Querying all the users in that queue

And updating another custom field(Queue_Members__c )  with all the users in that Queue 

My apex class is working fine  

Here is the apex class  - 

global class lookUpAccountAnnotation {
public class inputValues{
        @InvocableVariable(label='Queue ID' )
        public string QueueId;
        @InvocableVariable(label='Record Id' )
        public Id recordid;
        public string temp;
    }
   @InvocableMethod
    public static void deletePackageLicense(List<inputValues> inputs){
    
      for (inputValues i : inputs)
   {
     List<QueueDistroHelper__c> getcurrentobject =  [SELECT Queue_Members__c ,  Next_Queue_Reassignment_User__c  FROM QueueDistroHelper__c WHERE Id=:i.recordid ];
     
      List<User> users =  [SELECT
                    name
                FROM
                    user
                WHERE
                    id IN ( SELECT userOrGroupId FROM groupmember WHERE groupId =:i.QueueID)
                    AND
                    isActive = true
               
                ];
      for ( User test : users){
      if(getCurrentObject != null && !getCurrentObject .isEmpty()) {
if(getCurrentObject[0].Queue_Members__c == null)
   getCurrentObject[0].Queue_Members__c = '';
getCurrentObject[0].Queue_Members__c = getCurrentObject[0].Queue_Members__c + ' ' + test.name;
}

getCurrentObject[0].Next_Queue_Reassignment_User__c =+ users.get(1).name;
getCurrentObject[0].Last_Queue_Reassignment_User__c =+ users.get(0).name;


update getcurrentobject[0];


}   
      }
   }
}

I am trying to make a test class for the  same , Here are the steps I am doing for testing 

1. Creating 4 test users

2.Adding those users in a test queue

3. Updating my fields on my  Custom object with User name and Queue ID 

Not sure if its the right approach 

Here is my test Class - 

@isTest
private class lookUpAccountAnnotation_Test{
   @TestSetup
     static void setup() {    
    // Setup 4 Test Users
 Group grpObj = new Group(Type='Queue', Name='Test Queue1');
insert grpObj;
QueueSObject qObj = new QueueSObject(SobjectType='Lead', QueueId=grpObj.Id);
insert qObj;
    Profile p = [SELECT Id FROM Profile WHERE Name='Standard User']; 
    List<User> users = new List<User>();

    while (users.size() < 5) {
      Blob b = Crypto.GenerateAESKey(128);
      String h = EncodingUtil.ConvertTohex(b);
      String uid = h.SubString(0,8);
      //insert 4 test users
      User u = new User(Alias = uid, Email= uid + '@myorg.com', 
          EmailEncodingKey='UTF-8',LastName='Testing', LanguageLocaleKey='en_US', 
          LocaleSidKey='en_US', ProfileId = p.Id, 
          TimeZoneSidKey='America/New_York', UserName= uid + '@myorg.com');      
         ID gr = [SELECT Id FROM Group WHERE Name = 'Test Queue1'].Id;
         ID us = [SELECT Id , Name FROM User WHERE LastName='Testing'].Id;
         //Add one user in a test queuecreated above
        GroupMember gm = new GroupMember(GroupId = gr, UserOrGroupId = us);
           insert gm;
    }
System.Test.startTest();

QueueDistroHelper__c q = new QueueDistroHelper__c();
insert q;
//insert user name and Queue ID  in custom Object  
q.Related_Queue_Id__c = grpObj.Id;
q.Queue_Members__c = users.get(1).Name;
lookUpAccountAnnotation l = new lookUpAccountAnnotation();
//queryHelper q = new QueueDistroHelper__c(Name='TestQuery' , Queue_Members__c=users.name);    

System.Test.stopTest();

}
}