Postcondition
A postcondition is a condition that must be true after a test case or operation has completed successfully.
“The expected state of a test item and its test environment at the end of test execution.”
(Definition reproduced from the ISTQB Glossary. Copyright belongs to ISTQB.)
View the complete ISTQB GlossaryWhat is Postcondition?
Postconditions define the expected final state of the system and help ensure that testing leaves the environment in a predictable condition.
Final state: Describes expected system conditions after execution.
Validation: Confirms operations completed correctly.
Test management: Supports consistent test environments.
Real World Example
A travel platform is changing its refund policy for cancelled flights, with different outcomes depending on ticket type, cancellation time, loyalty status, and airline disruption reason.
No single happy-path test can cover the combinations. Postcondition helps the tester see which conditions must be varied together and which outcomes should result.
The tester maps the policy into compact rules, removes impossible combinations, and designs cases that prove each meaningful refund decision is handled correctly.
The team avoids contradictory refund behavior because Postcondition makes hidden rule combinations visible before customers start cancelling trips.
Practice Questions
Question 1
Which statement BEST describes Postcondition in the context of ISTQB terminology?
Question 2
A tester needs to explain Postcondition to a non‑technical stakeholder. Which approach is MOST appropriate?
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