Pseudo-oracle
A pseudo-oracle is a source used to estimate the correctness of software behavior when a true test oracle is unavailable.
“An independently derived variant of the test item used to generate results, which are compared with the results of the original test item based on the same test inputs.”
(Definition reproduced from the ISTQB Glossary. Copyright belongs to ISTQB.)
View the complete ISTQB GlossaryWhat is Pseudo-oracle?
Instead of providing guaranteed correct results, a pseudo-oracle offers a reasonable basis for comparing outputs, such as another implementation or previous software version.
Alternative reference: Used when exact expected results are unknown.
Comparison based: Results are evaluated against another trusted source.
Testing support: Useful for complex or scientific applications.
Real World Example
A regulated product team is preparing a release where Pseudo-oracle appears in reviews, test design conversations, or defect triage rather than as an isolated glossary word.
The risk is that the team treats Pseudo-oracle as interchangeable with nearby ISTQB terms. That makes test scope blurry and can lead to weak evidence for the release decision.
The tester anchors the discussion in the official definition, asks where the concept appears in the product, and designs examples that show the difference between Pseudo-oracle and similar ideas.
The page becomes useful in practice because Pseudo-oracle is connected to a specific testing decision, not memorized as a detached definition.
Practice Questions
Question 1
Which statement BEST describes Pseudo-oracle in the context of ISTQB terminology?
Question 2
A tester needs to explain Pseudo-oracle to a non‑technical stakeholder. Which approach is MOST appropriate?
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