ERP and packaged app testing is software that re-tests a company's customisations of a large bought system, such as SAP, Oracle or Workday, every time the vendor releases an update. A packaged application is a large business system that a company buys rather than builds. Enterprise resource planning (ERP) software, which runs a company's sales, purchasing, warehouses and accounts, is the most common example.
No company uses such a system exactly as it comes. Each company adapts it to its own business: its own approval rules, reports, forms and links to other systems. These changes are called customisations. In India, for example, companies add steps for GST e-invoices and e-way bills.
The problem is updates. Cloud ERP vendors now update their systems on a fixed schedule, often every quarter, for all their customers. A customer cannot refuse an update, and can delay it only a little. Each update can change a screen, a field or a rule that a customisation depends on. So before every update, the company must test all its customisations again. By hand, that can keep a team busy for several weeks, every quarter.
The testing tool automates this work. It records the company's business processes as automated tests, such as "raise a purchase order, get it approved, receive the goods, pay the supplier". Some tools read the system's own usage records to find which processes the company actually uses. When the vendor publishes an update, it is first installed in a test copy of the system. The tool runs every test there, and lists what broke before the update reaches the live system.
Take, for example, a two-wheeler maker in Pune that runs its factory and accounts on a cloud ERP. It has 650 automated tests for its customisations. One custom rule says that any purchase order above ₹10 lakh needs the plant head's approval. Two weeks before the quarterly update reaches the live system, the vendor installs it in the company's test copy. The tool runs all 650 tests overnight. 647 pass. Three fail: after the update, purchase orders above ₹10 lakh go straight through with no approval. The IT team fixes the rule in the test copy and runs the three tests again. They pass, so the company is ready when the update reaches the live system.
These tools are a specialised kind of test automation tool, built for systems that the company did not write. The custom code inside Salesforce has a similar need, handled by Salesforce DevOps tools. Packaged app testing is one step of software testing for any company whose business runs on bought systems.