global class UpdateCPortalContacts implements Schedulable {
    global void execute(SchedulableContext ctx) {

        Set<Id>conIds = new Set<Id>();
        
        List<User> UsersList = [select id,contactid,Gold_Partner_User__c,Customer_Portal_User__c 
                                FROM USER 
                                WHERE isActive=TRUE AND Customer_Portal_User__c = TRUE]; 
                                
       for(user u: UsersList){
            conIds.add(u.contactid);
        }                            
        
       List<contact> ContactList =[Select id,Customer_Portal_Lic_assigned__c 
                                   FROM contact 
                                   WHERE ID IN : conIds AND Customer_Portal_Lic_assigned__c=FALSE]; 
        if(!ContactList.isempty()){
                   for(contact c:ContactList){
           			 c.Customer_Portal_Lic_assigned__c=TRUE;            
        			}
        UPDATE ContactList;  
        }      
    }
}

@isTest
public class UpdateCPortalContactsTest {
public static string uId;    
@testsetup
    static void setup(){ // dummy
         contact c = new contact();
         c.LastName='gunwinder';
         c.email='goolied@gmail.com';
             
        insert c;     
       // https://help.salesforce.com/s/articleView?id=000330124&type=1
       // This error is generated because the user who running the code does not have a role.
       // Ensure that the user running the code below has a role assigned (eg. Sys Admin user does not have a role assigned by default).
       // To resolve the error, assign the User a Role. 
       
       UserRole userrole = [Select Id, DeveloperName From UserRole Where DeveloperName = 'System Administrator' Limit 1];

       User adminUser = [Select Id, UserRoleId From User Where Profile.Name='System Administrator' Limit 1];

	   adminUser.UserRoleId = userRole.Id;
	   update adminUser;
        
       System.runAs(adminUser){ 
       list <user> listofUsers = new list<user>();
       for (integer i=0;i<2;i++){
            user u = new user ( 
            username='goolied'+i+'@gmail.com',
            Email='goolied'+i+'@gmail.com',
            alias='gr'+ i,
            LastName='test user',
            TimeZoneSidKey='America/Los_Angeles',
            LocaleSidKey='en_US',           
            EmailEncodingKey='UTF-8',    
            ProfileId='00e0W0000026rzK',
            LanguageLocaleKey='en_US',    
            contactid=c.Id   
            );
        insert u; 
        uId = u.Id;
       }
       }
    }
        
    static testMethod void testDailySheduledJob(){
        string sch ='0 5 12 * * ?';
        Test.startTest();
        string jobjId = System.schedule('UpdateCPortalContacts', '0 0 14 * * ? *' , new UpdateCPortalContacts());
        list<user> userList = [select id from USER where id =: uId];
        integer ucheck=userList.size();
      //  system.asssetEquals(1,userList.size());
        Test.stopTest();
    }
}

• System.runAs(adminUser) or is it due to the limitation of how records are inserted. Since I am learning APEX I want to make sure If I should use it as rule of thumb (kind of boiler plate code) and always use in creating test classes.
• system.asssetEquals();