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name: acceptance-testing description: "Use when validating that implementation meets specification requirements — applies acceptance-driven backpressure with behavioral validation gates that prevent completion claims without passing tests. Triggers: spec-to-code validation, feature completion verification, pre-merge acceptance gate, release readiness check."

Acceptance Testing

Overview

Acceptance-driven backpressure connects specification acceptance criteria directly to test requirements, creating a validation chain that prevents premature completion claims. The system cannot cheat — you cannot claim a feature is done unless tests derived from spec acceptance criteria actually pass.

Announce at start: "I'm using the acceptance-testing skill to validate against specification criteria."

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The Backpressure Chain

+------------+     derives      +------------+     validates    +------------+
|   SPECS    |---------------->|   TESTS    |---------------->|   CODE     |
|            |                  |            |                  |            |
| Acceptance |                  | Test cases |                  | Must pass  |
| Criteria   |                  | from AC    |                  | all tests  |
+------------+                  +------------+                  +------------+
      ^                                                              |
      |                    backpressure                               |
      +--------------------------------------------------------------+
      If tests fail, implementation must change (not the spec or test)

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Phase 1: Extract Acceptance Criteria

Goal: From each specification file, extract all Given/When/Then acceptance criteria.

Actions

1. Locate all specification files (specs/*.md)
2. Extract every acceptance criterion with its ID
3. Document in structured format

Example Extraction

## From spec: 01-color-extraction.md

### AC-1: Extract dominant colors
- Given an uploaded image (PNG, JPG, or WebP)
- When color extraction is triggered
- Then 5-10 dominant colors are returned
- And each color includes hex, RGB, and HSL representations

### AC-2: Handle invalid images
- Given a corrupted or unsupported file
- When color extraction is attempted
- Then an appropriate error is returned
- And no partial results are produced

STOP — HARD-GATE: Do NOT proceed to Phase 2 until:

• All spec files are located and read
• Every acceptance criterion is extracted with an ID
• Criteria are in Given/When/Then format
• No criteria are ambiguous (if ambiguous, clarify with spec author)

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Phase 2: Derive Test Cases

Goal: Map every acceptance criterion to at least one test case.

┌─────────────────────────────────────────────────────────────────┐
│  HARD-GATE: Every acceptance criterion must have at least one   │
│  corresponding test. No exceptions. If a criterion has no       │
│  test, the feature is NOT complete.                             │
└─────────────────────────────────────────────────────────────────┘

Traceability Table

Acceptance Criterion	Test Type	Test Description	Test File:Line
AC-1: Extract dominant colors	Integration	Upload valid image, verify 5-10 colors with hex/RGB/HSL	test/color.test.js:15
AC-2: Handle invalid images	Integration	Upload corrupted file, verify error, verify no partial data	test/color.test.js:42

Decision Table: Test Type for Acceptance Criteria

Criterion Type	Test Type	Rationale
Data input/output behavior	Integration	Tests real data flow
Error handling behavior	Integration	Tests error paths end-to-end
Performance requirement	Load test	Requires measurement under load
UI behavior	E2E (Playwright)	Tests real browser interaction
Subjective quality	LLM-as-judge	Cannot be deterministically tested
Security requirement	Integration + security test	Tests authorization and input validation

STOP — HARD-GATE: Do NOT proceed to Phase 3 until:

• Every acceptance criterion has at least one test mapped
• Test types are appropriate for the criterion type
• Test file locations are identified

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Phase 3: Write Tests Before Implementation

Goal: Write acceptance tests that will fail until the feature is correctly implemented.

Actions

This phase integrates with test-driven-development:

1. Write test from acceptance criterion (RED)
2. Implement feature to pass test (GREEN)
3. Refactor while keeping test green (REFACTOR)

Behavioral Outcome Focus

Verify This (Behavioral)	NOT This (Implementation)
"5-10 colors are returned"	"K-means runs with k=8"
"Response time < 200ms"	"Cache is hit on second call"
"Error message is user-friendly"	"CustomError class is thrown"
"Data persists across sessions"	"PostgreSQL INSERT executes"
"UI updates within 500ms"	"WebSocket message is received"

STOP — HARD-GATE: Do NOT proceed to Phase 4 until:

• All acceptance tests are written
• Tests fail before implementation (RED confirmed)
• Tests verify behavioral outcomes, not implementation details

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Phase 4: Validation Gates

Goal: Before claiming any task complete, ALL gates must pass.

Gate	Check	Tool	Required
Unit tests	All pass	Test runner	Always
Integration tests	All pass	Test runner	Always
Acceptance tests	All AC-derived tests pass	Test runner	Always
Build	Compiles without errors	Build tool	Always
Lint	No violations	Linter	Always
Typecheck	No type errors	Type checker	When applicable

┌─────────────────────────────────────────────────────────────────┐
│  HARD-GATE: ACCEPTANCE                                         │
│                                                                 │
│  Cannot claim completion without ALL acceptance tests passing.  │
│  If any acceptance test fails, the feature is NOT done.        │
│  Fix the implementation, not the spec or the test.             │
└─────────────────────────────────────────────────────────────────┘

STOP — HARD-GATE: Do NOT proceed to Phase 5 until:

• All validation gates pass
• Acceptance tests pass with green status
• No gates are skipped or marked as "will fix later"

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Phase 5: Traceability Report

Goal: Produce a report linking every spec criterion to its test and result.

Report Template

## Acceptance Test Report

| Spec | Criterion | Test | Status |
|------|-----------|------|--------|
| 01-color-extraction.md | AC-1: Extract dominant colors | test/color.test.js:15 | PASS |
| 01-color-extraction.md | AC-2: Handle invalid images | test/color.test.js:42 | PASS |
| 02-palette-rendering.md | AC-1: Render palette grid | test/palette.test.js:8 | PASS |

### Summary
- Total criteria: N
- Tested: N
- Passing: N
- Failing: 0
- Coverage: 100%

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Anti-Patterns / Common Mistakes

Anti-Pattern	Why It Is Wrong	Correct Approach
Changing specs to match implementation	Defeats the purpose of specification	Fix the implementation, not the spec
Skipping edge case criteria	Edge cases cause production bugs	ALL acceptance criteria get tests
Testing implementation details	Brittle tests that break on refactor	Test observable behavioral outcomes
Claiming "tests pass" without acceptance tests	Unit tests alone are insufficient	Acceptance tests are a separate, required category
Writing acceptance tests after implementation	Tests shaped to pass, not to specify	Write BEFORE implementation (TDD)
Deferring acceptance tests to "later"	Later never comes	Write them in Phase 2, before coding
Marking failing tests as "known issues"	Hides incomplete implementation	Fix the code until tests pass

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Rationalization Prevention

Excuse	Reality
"The unit tests cover this"	Unit tests test components in isolation; acceptance tests verify integrated behavior
"The spec is obvious, no need for formal tests"	Obvious specs still need verifiable tests
"We can manually verify this"	Manual verification is not repeatable or trustworthy
"The acceptance criteria are too vague to test"	Clarify the criteria; vague specs produce vague code
"This is just a cosmetic change"	Cosmetic changes can break layout, accessibility, and UX

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Integration Points

Skill	Relationship
spec-writing	Acceptance criteria come from specs
test-driven-development	TDD cycle uses acceptance-derived tests
llm-as-judge	For subjective criteria that cannot be deterministically tested
verification-before-completion	Final verification includes acceptance test check
autonomous-loop	Exit gate requires acceptance tests passing
code-review	Review checks acceptance test coverage
planning	Plan includes acceptance test writing as explicit tasks

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Skill Type

RIGID — The backpressure chain must not be bypassed. Every acceptance criterion must have a test. No completion without passing acceptance tests. Fix the implementation, not the spec or the test.