An executable acceptance test turns part of a definition of done into a repeatable operation. It specifies the command, environment and success evidence needed to judge the result without relying on a narrative status report.
A trustworthy check requires both a successful process exit and the expected decisive output when output is part of the proof. The command itself must also be reviewed when it can change files, access credentials or affect external systems.
ELI5
An executable acceptance test is a command that checks whether a specific requirement has been met. It turns part of the definition of done into repeatable evidence instead of relying only on someone's claim that the work is complete.
For example, a test can open a sample order, apply a discount, and verify the exact total. The test must finish successfully and show the expected result, and reviewers should understand any files or systems the command can change.
