Test M0 with M1, M2, M3, M4, and stub for M5. Test M0 with M1, M2, M3, M4, and M5. Most of mainframe legacy systems can use the Top-down testing because the mainframe legacy systems use procedural type language such as Cobol. Object-oriented software does not have a hierarchical control structure unlike the procedure languages. Thread testing works great with real-time systems that has a need to respond to an event.
Stress testing works great with testing maximum workload.
It does not respond to an event but to control. These modules are most-likely objects. As testing works it way up through the chain of objects then drivers are removed and replaced by other objects and new driver is now controlling the testing. Test objects OO7 with driver for OO7 only. Test objects OO5, OO7 with driver for OO5 only.