Recommendations for testing new functionality/changes in production environment?

Summary: It is difficult to test changes in the production environment which would require us to create/post a "fake" requisition or "fake" candidates or offers. Do you have any suggestions for doing so? Additional complexity is we are a government contractor so don't want to have extra noise in the system and I know once we submit a req, you can only mark it as canceled and not fully delete it.

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