Can i get a SQL Server catch Updates to reflect the responsible objectid with a database trigger?
if you want to know who wrote what and when,
I would create 2 users, one for each of the procedures involved, and then 
create procedures with execute as user

add an extra column on your testtable to keep the session_user or current_user so that you know who inserted/updated each record since insert_procedure will be executed as insert_user and update_procedure will be executed as update_user.

this script can help you to find out the original login, and compares different ways of addressing the users.

DECLARE @User VARCHAR(20)
SELECT @USER = SUBSTRING(SUSER_SNAME(), 
               CHARINDEX('\', 
               SUSER_SNAME()) + 1, 
               LEN(SUSER_SNAME()))


SELECT   @USER 
        , SUSER_SNAME()
        ,SYSTEM_USER
        , USER_NAME()
        , CURRENT_USER
        , ORIGINAL_LOGIN()
        ,USER
        ,SESSION_USER


EXECUTE AS LOGIN='my_user'

--DECLARE @User VARCHAR(20)
SELECT @USER = SUBSTRING(SUSER_SNAME(), 
               CHARINDEX('\', 
               SUSER_SNAME()) + 1, 
               LEN(SUSER_SNAME()))


SELECT   @USER 
        , SUSER_SNAME()
        ,SYSTEM_USER
        , USER_NAME()
        , CURRENT_USER
        , ORIGINAL_LOGIN()
        , USER
        ,SESSION_USER

REVERT