marsai:dev-unit-testing

Dev Unit Testing (Gate 3)

Overview

Ensure every acceptance criterion has at least one unit test proving it works. Follow TDD methodology: RED (failing test) -> GREEN (implementation) -> REFACTOR.

Core principle: Untested acceptance criteria are unverified claims. Each criterion MUST map to at least one executable unit test.

<block_condition>

• Coverage below 85% = FAIL
• Any acceptance criterion without test = FAIL </block_condition>

Coverage threshold: 85% minimum (MarsAI standard). PROJECT_RULES.md can raise, not lower.

CRITICAL: Role Clarification

This skill ORCHESTRATES. QA Analyst Agent EXECUTES.

Who	Responsibility
This Skill	Gather requirements, dispatch agent, track iterations
QA Analyst Agent	Write tests, run coverage, report results

---

Step 1: Validate Input

REQUIRED INPUT (from marsai:dev-cycle orchestrator):
<verify_before_proceed>
- unit_id exists
- acceptance_criteria is not empty
- implementation_files is not empty
- language is valid (typescript|python)
</verify_before_proceed>

```text
- unit_id: [task/subtask being tested]
- acceptance_criteria: [list of ACs to test]
- implementation_files: [files from Gate 0]
- language: [typescript|python]

OPTIONAL INPUT:
- coverage_threshold: [default 85.0, cannot be lower]
- gate0_handoff: [full Gate 0 output]
- existing_tests: [existing test files]

if any REQUIRED input is missing:
  → STOP and report: "Missing required input: [field]"
  → Return to orchestrator with error

if coverage_threshold < 85:
  → STOP and report: "Coverage threshold cannot be below MarsAI minimum (85%)"
  → Use 85% as threshold

Step 2: Initialize Testing State

testing_state = {
  unit_id: [from input],
  coverage_threshold: max(85, [from input]),
  coverage_actual: null,
  verdict: null,
  iterations: 0,
  max_iterations: 3,
  traceability_matrix: [],
  tests_written: 0,
}

Step 3: Dispatch QA Analyst Agent

<dispatch_required agent="marsai:qa-analyst"> Write unit tests for all acceptance criteria with 85%+ coverage. </dispatch_required>

Task:
  subagent_type: "marsai:qa-analyst"
  description: "Write unit tests for [unit_id]"
  prompt: |
    ⛔ WRITE UNIT TESTS for All Acceptance Criteria

    ## Input Context
    - **Unit ID:** [unit_id]
    - **Language:** [language]
    - **Coverage Threshold:** [coverage_threshold]%

    ## Acceptance Criteria to Test
    [list acceptance_criteria with AC-1, AC-2, etc.]

    ## Implementation Files to Test
    [list implementation_files]

    ## Standards Reference
    For TS: https://raw.githubusercontent.com/V4-Company/marsai/main/dev-team/docs/standards/typescript.md

    Focus on: Testing Patterns section

    ## Requirements

    ### Test Coverage
    - Minimum: [coverage_threshold]% branch coverage
    - Every AC MUST have at least one test
    - Edge cases REQUIRED (null, empty, boundary, error conditions)

    ### Test Naming
    - TS: `describe('{Unit}', () => { it('should {scenario}', ...) })`

    ### Test Structure
    - One behavior per test
    - Arrange-Act-Assert pattern
    - Mock all external dependencies
    - no database/API calls (unit tests only)

    ### Edge Cases Required per AC Type

    <cannot_skip>
    - Minimum 3 edge cases per AC type
    - null, empty, boundary conditions required
    - Error conditions required
    </cannot_skip>

    | AC Type | Required Edge Cases | Minimum |
    |---------|---------------------|---------|
    | Input validation | null, empty, boundary, invalid format | 3+ |
    | CRUD operations | not found, duplicate, concurrent | 3+ |
    | Business logic | zero, negative, overflow, boundary | 3+ |
    | Error handling | timeout, connection failure, retry | 2+ |

    ## Required Output Format

    ### Test Files Created
    | File | Tests | Lines |
    |------|-------|-------|
    | [path] | [count] | +N |

    ### Coverage Report
    **Command:** [coverage command]
    **Result:**
    ```
    [paste actual coverage output]
    ```

    | Package/File | Coverage |
    |--------------|----------|
    | [name] | [X%] |
    | **TOTAL** | **[X%]** |

    ### Traceability Matrix
    | AC ID | Criterion | Test File | Test Function | Status |
    |-------|-----------|-----------|---------------|--------|
    | AC-1 | [criterion text] | [file] | [function] | ✅/❌ |
    | AC-2 | [criterion text] | [file] | [function] | ✅/❌ |

    ### Quality Checks
    | Check | Status |
    |-------|--------|
    | No skipped tests | ✅/❌ |
    | No assertion-less tests | ✅/❌ |
    | Edge cases per AC | ✅/❌ |
    | Test isolation | ✅/❌ |

    ### VERDICT
    **Coverage:** [X%] vs Threshold [Y%]
    **VERDICT:** PASS / FAIL
    
    If FAIL:
    - **Gap Analysis:** [what needs more tests]
    - **Files needing coverage:** [list with line numbers]

Step 4: Parse QA Analyst Output

Parse agent output:

1. Extract coverage percentage from Coverage Report
2. Extract traceability matrix
3. Extract verdict

testing_state.coverage_actual = [extracted coverage]
testing_state.traceability_matrix = [extracted matrix]
testing_state.tests_written = [count from Test Files Created]

if verdict == "PASS" and coverage_actual >= coverage_threshold:
  → testing_state.verdict = "PASS"
  → Proceed to Step 6

if verdict == "FAIL" or coverage_actual < coverage_threshold:
  → testing_state.verdict = "FAIL"
  → testing_state.iterations += 1
  → if iterations >= max_iterations: Proceed to Step 7 (Escalate)
  → Proceed to Step 5 (Dispatch Fix)

Step 5: Dispatch Fix to Implementation Agent

Coverage below threshold → Return to Gate 0 for more tests

Task:
  subagent_type: "[implementation_agent from Gate 0]"  # e.g., "marsai:backend-engineer-typescript"
  description: "Add tests to meet coverage threshold for [unit_id]"
  prompt: |
    ⛔ COVERAGE BELOW THRESHOLD - Add More Tests

    ## Current Status
    - **Coverage Actual:** [coverage_actual]%
    - **Coverage Threshold:** [coverage_threshold]%
    - **Gap:** [threshold - actual]%
    - **Iteration:** [iterations] of [max_iterations]

    ## Gap Analysis (from QA)
    [paste gap analysis from QA output]

    ## Files Needing Coverage
    [paste files list from QA output]

    ## Requirements
    1. Add tests to cover the identified gaps
    2. Focus on edge cases and error paths
    3. Run coverage after each addition
    4. Stop when coverage >= [threshold]%

    ## Required Output
    - Tests added: [list]
    - New coverage: [X%]
    - Coverage command output

After fix → Return to Step 3 (Re-dispatch QA Analyst)

Step 6: Prepare Success Output

Generate skill output:

## Testing Summary
**Status:** PASS
**Unit ID:** [unit_id]
**Iterations:** [testing_state.iterations]

## Coverage Report
**Threshold:** [coverage_threshold]%
**Actual:** [coverage_actual]%
**Status:** ✅ PASS

| Package/File | Coverage |
|--------------|----------|
[from QA output]
| **TOTAL** | **[coverage_actual]%** |

## Traceability Matrix
| AC ID | Criterion | Test | Status |
|-------|-----------|------|--------|
[from testing_state.traceability_matrix]

**Criteria Covered:** [X]/[Y] (100%)

## Quality Checks
| Check | Status |
|-------|--------|
| Coverage ≥ threshold | ✅ |
| All ACs tested | ✅ |
| No skipped tests | ✅ |
| Edge cases present | ✅ |
## Handoff to Next Gate
- Testing status: COMPLETE
- Coverage: [coverage_actual]% (threshold: [coverage_threshold]%)
- All criteria tested: ✅
- Ready for Gate 4 (Review): YES

Step 7: Escalate - Max Iterations Reached

Generate skill output:

## Testing Summary
**Status:** FAIL
**Unit ID:** [unit_id]
**Iterations:** [max_iterations] (MAX REACHED)

## Coverage Report
**Threshold:** [coverage_threshold]%
**Actual:** [coverage_actual]%
**Gap:** [threshold - actual]%
**Status:** ❌ FAIL

## Gap Analysis
[from last QA output]

## Files Still Needing Coverage
[from last QA output]

## Handoff to Next Gate
- Testing status: FAILED
- Ready for Gate 4: no
- **Action Required:** User must manually add tests or adjust scope

⛔ ESCALATION: Max iterations (3) reached. Coverage still below threshold.
User intervention required.

---

Severity Calibration

Severity	Criteria	Examples
CRITICAL	Test infrastructure broken, no coverage possible	Test framework failure, build broken
HIGH	Coverage below threshold, missing AC tests	84% coverage (below 85%), untested acceptance criteria
MEDIUM	Test quality issues, edge case gaps	Missing edge case tests, poor assertion messages
LOW	Test naming, documentation gaps	Non-standard test names, missing test descriptions

Report all severities. CRITICAL/HIGH = immediate fix. MEDIUM = fix in iteration. LOW = document for follow-up.

---

Pressure Resistance

See shared-patterns/shared-pressure-resistance.md for universal pressure scenarios.

User Says	Your Response
"84% is close enough"	"85% is minimum threshold. 84% = FAIL. Adding more tests."
"Manual testing covers it"	"Gate 3 requires executable unit tests. Dispatching QA analyst."
"Skip testing, deadline"	"Testing is MANDATORY. Untested code = unverified claims."

---

Anti-Rationalization Table

See shared-patterns/shared-anti-rationalization.md for universal anti-rationalizations.

Gate 3-Specific Anti-Rationalizations

Rationalization	Why It's WRONG	Required Action
"Tool shows 83% but real is 90%"	Tool output IS real. Your belief is not.	Fix issue, re-measure
"Excluding dead code gets us to 85%"	Delete dead code, don't exclude it.	Delete dead code
"84.5% rounds to 85%"	Rounding is not allowed. 84.5% < 85%.	Write more tests
"Close enough with all AC tested"	"Close enough" is not passing.	Meet exact threshold
"Integration tests cover this"	Gate 3 = unit tests only. Different scope.	Write unit tests

Unit Test vs Integration Test

Type	Characteristics	Gate 3?
Unit ✅	Mocks all external deps, tests single function	YES
Integration ❌	Hits real database/API/filesystem	no

---

Execution Report Format

## Testing Summary
**Status:** [PASS|FAIL]
**Unit ID:** [unit_id]
**Duration:** [Xm Ys]
**Iterations:** [N]

## Coverage Report
**Threshold:** [X%]
**Actual:** [Y%]
**Status:** [✅ PASS | ❌ FAIL]

## Traceability Matrix
| AC ID | Criterion | Test | Status |
|-------|-----------|------|--------|
| AC-1 | [text] | [test] | ✅/❌ |

**Criteria Covered:** [X/Y]

## Handoff to Next Gate
- Testing status: [COMPLETE|FAILED]
- Coverage: [X%]
- Ready for Gate 4: [YES|no]