Max of Row Number Logic

Hi,

Below are my table structure

create table Test (ProductId int primary key identity(1,1), productnumber varchar(50),productname varchar(50),Quantity int)

insert into Test values('PN1001','Pepsi',20),
  ('PN1001','curd',2),
 ('PN1001','Noodles',10),
 ('PN1001','Shrimp',40),
  ('PN1002','Mango',10),
 ('PN1002','Pizza',5),
 ('PN1002','Soup',10),
 ('PN1002','Honey',30),
  ('PN1001','Pepsi',15),
 ('PN1001','Curd',50),
 ('PN1001','Noodles',13),
 ('PN1001','Shrimp',32),
  ('PN1002','Mango',11),
 ('PN1002','Pizza',14),
 ('PN1002','Soup',18),
 ('PN1002','Honey',20)

I need to take the last inserted set of records. unfortunately i don't have created date in my table and not sure why it hasn't created when the guy build the table schema. i know this is poor table structure cannot do anything at the moment.

Me required output :

select 'PN1001' as productnumber,'Pepsi' as productname,15 as Quantity union all
 select 'PN1001' as productnumber,'curd' as productname,50 as Quantity union all
 select 'PN1001' as productnumber,'Noodles' as productname,13 as Quantity union all
 select 'PN1001' as productnumber,'Shrimp' as productname,32 as Quantity union all
 select 'PN1002' as productnumber,'Mango' as productname,11 as Quantity union all
 select 'PN1002' as productnumber,'Pizza' as productname,14 as Quantity union all
 select 'PN1002' as productnumber,'Soup' as productname,18 as Quantity union all
 select 'PN1004' as productnumber,'Honey' as productname,20 as Quantity 

ie. The logic i need to achieve is to get the last insert records based on productnumber.

This is my try

;with TotalRecords as (

select ROW_NUMBER() OVER 
(PARTITION BY productnumber
Order BY productnumber DESC ) 
AS RowNumber,productnumber, productname,Quantity from Test)
 
 select * from TotalRecords

loving dotnet