Entry criteria are the conditions that must be met BEFORE a testing phase can begin; Exit criteria are the conditions that must be satisfied before a phase can be considered COMPLETE and testing can stop or move on.
ENTRY criteria for test execution might include: requirements finalized, test cases reviewed/approved, test environment ready, test data prepared, and a stable build deployed. EXIT criteria might include: all planned test cases executed, a required pass rate met, no open critical/high defects, defect trends stabilized, and the RTM showing full coverage. These criteria make phase transitions objective rather than arbitrary — you don't start executing on an unready environment, and you don't declare 'done' with critical bugs open. They're defined in the test plan and are a key part of test management and a common interview topic.
Test execution won't START until the build is deployed to staging and test data is loaded (entry); it won't be declared COMPLETE until 100% of planned cases run, no critical/high defects remain open, and pass rate ≥ 95% (exit).
How do you decide when testing is 'done' and it's safe to stop?