The goal of end-to-end testing is to simulate real business, from data migration to new product and customer creation; using this data for placing orders, fulfillment, invoicing, receiving cash, reverse logistics, transactions using migrated data, to verify reporting, and so on.

Similar to UAT, you need to publish reports on the test results and follow a triage process. Areas that are blocked during testing need to be unblocked and tested again. Assess whether you have met the exit criteria and review it with the executives.

The project team should come up with all the key business scenarios that should be tested. The following are a few examples of the areas on which you should focus during end-to-end testing:

• Customer invoicing: The timing and accuracy of invoicing customers is such a critical business function because it has a direct impact on both the customer and on the cash flow of the company. On the other hand, invoicing is a downstream function – you have a dependency on products, customers, tax, fulfillment processes, and so on – which must work correctly before you can produce the invoices.
• Commission reporting: As commission reporting has an impact on the paychecks of the sales floor, you need to verify the accuracy of the commission reports with migrated orders and invoices. It should be a top priority, as you want the sales team to trust the system and focus on selling (rather than tracking) their orders on spreadsheets for an expected commission, or worrying whether they'll be paid. Commission reporting can be even trickier for orders shipped in the previous system, and you may have to pay a commission upon receiving customer payments.
• Inventory costing and valuation: Each customer has a different way of using a weighted average, FIFO (short for First-In, First-Out), and other inventory-costing methods. It impacts the profit and loss statement, their bottom line, how executives are compensated, the inventory value on the balance sheet, and so on. Efforts need to be put in during UAT and end-to-end testing in order to validate that the inventory costing is done according to the needs of the company, and that it is understood by the financial controllers and the rest of the stakeholders.

• General ledger postings: You need to verify the posting for each type of transaction, and run month-end reconciliation reports (to verify that the general ledger and sub-ledger are in balance).
• Key reports: Identify the key reports that are important to run the business, and validate the data based on the transactions that were processed in end-to-end testing.

Once testing areas are well planned, it is highly important to impart sufficient training to users as their daily work life is going to change with the new system. In the next section, we will cover the details of training, tools, preparation, execution, and environment planning.