Testing, ERP Style
ERP systems are transaction-focused by nature; adapters, connectors, applications, and integration points can't be run on production data. Instead, you must create a test region to run an instance of your ERP system. For many manufacturing companies, this is cost-prohibitive. There's no room in the budget for an SAP instance just used for testing.
Just as with other ERP systems, a replicated set of production data is required. If you're looking to test in an SAP environment specifically, check out Gamma Enterprise Technologies' InfoShuttle product for this purpose. Their expertise in ABAP programming is extensive and proven in several large implementations.
Test plans need to include testing of wide variations in Bills of Materials, custom order requirements, supply-chain system integration, and especially pricing. Having an idea of how your databases are performing in each of these integration points helps to spot potential trouble areas; for example, if your ERP system times out when waiting for specific Bill of Material components.