How to Insert Record to User Object in Test Class

public  class exmaple_Test{

    private static String generateRandomString() {

        return '' + math.rint( math.random() * 100000 );

    }

    

    

static  testmethod  void method1()

{

test.starttest();

    System.runAs ( new User(Id = UserInfo.getUserId()) ) {

        

       

     List<User> u =[select Id from User where PM_Qualified__c=true LIMIT 1];

    List<Profile> prf=[SELECT Id, Name FROM Profile where Name='System Administrator'];

    User userToCreate = new User();

userToCreate.FirstName=  'Bonface';

userToCreate.LastName = 'Kambona';

  userToCreate.Username = 'testUser-' + generateRandomString() + '@test.com';

        userToCreate.Email = 'testUser-' + generateRandomString() + '@test.com';

userToCreate.Alias = 'fatty';

userToCreate.ProfileId = prf[0].Id;

userToCreate.TimeZoneSidKey = 'America/New_York';

userToCreate.LocaleSidKey = 'en_US';

userToCreate.EmailEncodingKey = 'UTF-8';

userToCreate.LanguageLocaleKey = 'en_US';

 userToCreate.PM_Qualified__c=true;   

  userToCreate.isactive=true;  

insert userToCreate;

}

}

}