Find Which Testing Question Was Actually Answered
The Testing Stack
Companion to You Are Not the User · Updated 2026-09-29
Use this when someone says “we tested it” and you need to know which of the six questions was actually answered. Worked in “‘We Tested It’ Means Almost Nothing.”
The Testing Stack for one release: what each layer tested and what its result proves.
| Layer | Question it answers | What we tested | Result | What the pass proved |
|---|---|---|---|---|
| Unit testing | Does this small piece of code behave correctly? | |||
| Integration testing | Do the pieces communicate correctly? | |||
| System testing | Does the assembled system behave to specification? | |||
| Quality Assurance (QA) | Did we systematically verify the product works as intended? | |||
| User acceptance testing (UAT) | Can the intended user accomplish the intended real-world job? | |||
| Production evidence | What actually happens when people use it at scale? |
The first four rows test the software against the specification. The last two test the specification against the work. A release with four passes in the first four rows and nothing in the last two has proved it was built as written, and nothing about whether what was written was right.