You work for a company who are pioneers in smart energy technology. One of their core products is their energy monitor in-home display device, used to display current and historic energy consumption…

You work for a company who are pioneers in smart energy technology. One of their core products is their energy monitor in-home display device, used to display current and historic energy consumption data to many thousands of customers. It has been designed to integrate with their other smart home products, including domestic lighting control systems via their HomeHub. The energy monitor in-home display device has been designed to interact with the home's lighting system and automatically dim bedroom lights when the daily energy budget has reached 90%. A defect has been found in the energy monitor's software which causes lights to be dimmed at 80% of the daily budget. What type of testing would MOST likely have uncovered this defect?