yknothing Acceptance Criteria
If you can't test it, you can't ship it. Acceptance criteria make requirements verifiable.
Context
Acceptance criteria bridge the gap between "what we want" (requirements) and "how we verify it works" (tests).
See context and anti-pattern notes.
Inputs
I/O contract notes define required inputs and authority.
Process
Step 1: Choose a Format
Use Given-When-Then (Gherkin) for behavior-driven criteria:
Given [precondition]
When [action]
Then [expected result]
Or use checklist format for simpler requirements:
- [ ] User can reset password via email link
- [ ] Link expires after 24 hours
- [ ] User sees error if link is expired
Step 2: Cover Happy Path and Edge Cases
For each requirement, write criteria for:
- Happy path: Normal, expected usage
- Edge cases: Boundary values, empty inputs, maximum limits
- Error paths: Invalid input, permission denied, network failure
- Security paths: Unauthorized access, injection attempts
Step 3: Make Criteria Measurable
Bad: "Page loads quickly" Good: "Page loads in under 2 seconds on 3G connection with 95th percentile"
Bad: "System handles many users" Good: "System supports 500 concurrent users with < 200ms response time at p95"
Step 4: Review with QA
QA engineers are expert at finding missing edge cases. Review criteria with them before finalizing. They should be able to write test cases directly from acceptance criteria.
Outputs
Produce only declared outputs at their documented quality boundary.
Quality Gate
- Every P0/P1 requirement has at least one acceptance criterion
- Happy path, edge cases, and error paths covered for critical features
- All criteria are measurable and testable
- QA team has reviewed and approved