test-strength

name	test-strength
description	Audits generated test strength on changed files using deterministic coverage and mutation measurement, then judges only surviving-mutant materiality.
contract_version	1.0.0
side_effect_profile	mutating

Why This Exists

Passing tests are necessary but not sufficient. SWE-ABS-style test strength asks whether the generated verifier suite actually exercises the changed code and detects wrong behavior instead of merely replaying the happy path. This skill keeps coverage and mutation measurement deterministic, and uses LLM judgement only when surviving mutants still need interpretation.

Trigger

Run at phase 4 after qa passes and before slop_gate. In repos where slop_gate is still implicit, run after qa and before the next delivery gate.

Inputs

Use these inputs:

• changed files from git diff
• generated tests from .adlc/test_plan.json
• language-appropriate mutation config

Mutation tooling is optional at the repo level, but not optional for a passing audit. If the repo language is unsupported or the standard mutator is unavailable, emit stuck instead of silently passing.

Judgement is not optional once mutants survive. Use mutant-materiality-judge via the active runtime's deep_judge slot to classify surviving mutants in batches.

Supported Language Detection

Detect the dominant repo language from changed files and repo conventions:

• Python -> mutmut
• JavaScript or TypeScript -> stryker
• Rust -> cargo-mutants

If the changed files span multiple supported languages, audit the language that owns the generated tests in .adlc/test_plan.json and record the rationale in the report.

Audit Workflow

1. Read .adlc/test_plan.json and collect the generated test paths plus their target acceptance criteria.
2. Compute changed executable lines from git diff for the files under audit.
3. Run the generated tests with coverage scoped to the changed files.
4. Calculate coverage diff on changed executable lines only.
5. Detect the repo language and the standard mutation tool for that language.
6. Run mutation analysis on the changed files only.
7. If mutants survive, batch the surviving-mutant diffs and classify each survivor with mutant-materiality-judge as trivial or material.
8. Write .adlc/test_strength_report.json with thresholds, per-file coverage, mutant counts, surviving-mutant classifications, language detection rationale, and the verdict, then write the canonical audit copy to the path returned by bin/adlc process-artifact-path --target-repo <target-repo> --task <task-id> --artifact-type audit --filename test-strength.json --json.

Gates

Coverage Diff

• Threshold: >= 80% of changed executable lines must be covered by the generated tests.
• Use the generated tests from .adlc/test_plan.json as the audit scope, not the whole suite.
• Coverage is measured per changed file and summarized across the changed-file set.

Mutation Survival

• Threshold: >= 60% mutation kill rate on changed files.
• Use the language's standard mutator:
  • Python -> mutmut
  • JavaScript / TypeScript -> stryker
  • Rust -> cargo-mutants
• If the mutator is unsupported or unavailable, emit stuck.
• If any mutants survive, classify those survivors with mutant-materiality-judge.
• Any material surviving mutant forces the overall verdict to weak, even when the aggregate kill rate is still above 0.6.

Output

Write .adlc/test_strength_report.json for the local workflow handoff and store the canonical audit copy in ADLC process artifact storage.

{
  "$schema": "http://json-schema.org/draft-07/schema#",
  "title": "ADLC Test Strength Report",
  "type": "object",
  "additionalProperties": false,
  "required": [
    "report_path",
    "language",
    "language_detection_rationale",
    "coverage_threshold",
    "mutation_threshold",
    "files",
    "mutants_generated",
    "mutants_killed",
    "kill_rate",
    "verdict"
  ],
  "properties": {
    "report_path": {
      "type": "string",
      "const": ".adlc/test_strength_report.json"
    },
    "language": {
      "type": "string",
      "enum": ["python", "javascript", "typescript", "rust", "unknown"]
    },
    "language_detection_rationale": {
      "type": "string",
      "minLength": 1
    },
    "coverage_threshold": {
      "type": "number",
      "const": 0.8
    },
    "mutation_threshold": {
      "type": "number",
      "const": 0.6
    },
    "files": {
      "type": "array",
      "minItems": 1,
      "items": {
        "type": "object",
        "additionalProperties": false,
        "required": [
          "path",
          "changed_executable_lines",
          "covered_changed_lines",
          "coverage_ratio"
        ],
        "properties": {
          "path": {
            "type": "string",
            "minLength": 1
          },
          "changed_executable_lines": {
            "type": "integer",
            "minimum": 0
          },
          "covered_changed_lines": {
            "type": "integer",
            "minimum": 0
          },
          "coverage_ratio": {
            "type": "number",
            "minimum": 0,
            "maximum": 1
          }
        }
      }
    },
    "mutants_generated": {
      "type": "integer",
      "minimum": 0
    },
    "mutants_killed": {
      "type": "integer",
      "minimum": 0
    },
    "kill_rate": {
      "type": "number",
      "minimum": 0,
      "maximum": 1
    },
    "verdict": {
      "type": "string",
      "enum": ["pass", "weak", "stuck"]
    },
    "stuck_reason": {
      "type": "string"
    }
  }
}

Failure Modes

• Coverage diff below 0.8 -> emit weak.
• Mutation kill rate below 0.6 -> emit weak.
• Any material surviving mutant -> emit weak.
• Unsupported repo language -> emit stuck.
• Standard mutator unavailable -> emit stuck.
• Missing or invalid .adlc/test_plan.json -> emit stuck.

Weak findings are for test strengthening, not for waving away. The current DAG routes weak into the repair loop; that loop must return through test authoring before the next audit, and the retry budget is capped at test_strength_retry = 2.

Quality Gates

Before emitting pass, weak, or stuck, confirm:

1. .adlc/test_strength_report.json parses against the schema in this skill.
2. The report records coverage_threshold as 0.8 and mutation_threshold as 0.6.
3. The report includes a non-empty language_detection_rationale.
4. The ADLC-side audit copy path was computed with bin/adlc process-artifact-path.
5. No threshold is silently defaulted or omitted.

Output Labels

• pass: both thresholds met
• weak: coverage or mutation strength below threshold
• stuck: no supported language, no available standard mutator, or invalid audit input