A Solution Acceptance Test (SAT) is set of key business processes that you need your ERP solution to deliver in order to run your business.
It represents a Minium Viable Solution (MVS).
It helps if you start your selection by defining your SAT process set. Of course this process set will be amended as you go through your selection and implementation process and learn more about your solution. But if you have the end in sight when you start your selection, you are more likely to get there.
The SAT approach involves:
deciding and defining your SAT process set
agreeing the SAT process set with your vendor/partner
managing iterative SAT playbacks until the SAT can be accepted
Step 1 takes a lot of work with the project delivery team, who are also involved in step 3. There are likely to be multiple playbacks before a SAT process can be 'accepted' by the delivery team process leads.
Once all the SAT processes are accepted, and not until then, the steering team can authorize the project to move forward to the various deployment stages e.g. data migration, UAT, training etc.
The SAT is NOT the same as a Proof-of-Concept (POC) as the intention of the SAT is to provide reasonable assurance that you could run your business on the solution if the SAT is accepted.