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If you specify either of the options to validate rollback scripts, then you must provide -rollback or _rollback files for all scripts in the project.  The requirement starts when you enable the option. You do not need to provide rollback files for SQL scripts that have already been packaged and deployed. 

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1. Snapshot the REF database for comparison purposes (snapshot #1)
2. Deploy changes using SQL scripts provided (not logged in audit databaseDMCDB)
3. Snapshot the REF database again (snapshot #2)
4. Test rollback (not logged in audit databaseDMCDB)
5. Snapshot the REF database again (snapshot #3)
6. Deploy using generated changesets (not logged in audit databaseDMCDB) 
7. Snapshot the REF database one final time (snapshot #4)
8. Compare snapshot #1 and snapshot #3 to ensure rollback works properly
9. Compare snapshot #2 and snapshot #4 to ensure that script packaging works properly.

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Rollback Files and Developer Workflow Files

Do not use both -rollback/_rollback files and AND also Developer Workflow files (-cleanup/_cleanup, -replace/_replace, -ignore/_ignore) for the same SQL script. In general, Developer Workflow functionality is intended for SQL scripts that do not have -rollback/_rollback files. See /wiki/spaces/DDD/pages/80445460

See Developer Workflows: Managing Changesets during Deployment and Test