Ln 638 Test Oracle Effectiveness Auditor

Paths: File paths (references/, ../ln-*) are relative to this skill directory.

Test Oracle Effectiveness Auditor (L3 Worker)

Type: L3 Worker

Specialized worker auditing whether tests have meaningful oracles that would catch real product defects.

Purpose & Scope

• Audit Test Oracle Effectiveness (Category 9: Medium Priority)
• Identify tests that execute code but prove little
• Check assertion strength, semantic oracle quality, over-mocking, weak snapshots, and mutation-style evidence when available
• Emit STRENGTHEN_ORACLE, DELETE_WEAK_ORACLE, or ADD_MUTATION_EVIDENCE
• Calculate compliance score (X/10)

Inputs

MANDATORY READ: Load references/audit_worker_core_contract.md.

Receives contextStore with: tech_stack, testFilesMetadata, codebase_root, output_dir.

Workflow

Detection policy: use two-layer detection (candidate scan, then context verification); load references/two_layer_detection.md only when the verification method is ambiguous.

1. Parse Context: Extract tech stack, test file list, codebase_root, and output_dir from contextStore
2. Find weak-oracle candidates (Layer 1): Scan automated tests for no assertions, vague assertions, snapshot-only tests, excessive mocks, and mutation-test survivors when reports exist
3. Context Analysis (Layer 2 -- MANDATORY): For each candidate, ask:
   • Is this an intentional smoke test whose only contract is "starts without crashing"? -> downgrade or skip unless it masks critical behavior
   • Is a snapshot paired with semantic assertions? -> skip snapshot-only finding
   • Does the mock verify a product-side contract at the boundary? -> skip over-mocking finding
   • Is mutation evidence absent? -> do not require mutation testing except for critical modules with already weak oracles
4. Collect Findings: Record each confirmed issue with severity, location, effort, action, and recommendation
5. Calculate Score: Count violations by severity, calculate compliance score (X/10)
6. Write Report: Build full markdown report in memory per references/templates/audit_worker_report_template.md, write to {output_dir}/ln-638--global.md in single Write call
7. Return Summary: Return minimal summary to coordinator (see Output Format)

Audit Rules

1. Assertion Strength

What: Tests with no assertions, vague assertions, or assertions that would pass for many broken implementations

Detection:

• Tests that call production code without expect, assert, should, or framework-specific verification
• Vague assertions such as toBeTruthy, toBeDefined, not.toThrow, or status-only checks when domain values matter
• Exception tests that do not verify error type/message/state

Layer 2:

• Skip framework-generated smoke tests unless they are the only coverage for a critical path
• Downgrade simple existence checks when the product contract is explicitly existence-only

Severity: HIGH for critical logic, MEDIUM otherwise

Recommendation: Assert the product-specific output, state transition, side effect, emitted event, or persisted data that would fail under a real regression

Effort: S-M Action: STRENGTHEN_ORACLE, or DELETE_WEAK_ORACLE if the test has no product signal

2. Meaningful Oracle

What: Tests whose expected result is not tied to product behavior

Detection:

• Assertions only check object existence, array length, HTTP status, rendered container presence, or mock-call count when richer domain behavior is available
• Expected values mirror the implementation instead of an independent business rule or known example

Severity: MEDIUM

Recommendation: Replace structural assertions with behavior-level assertions derived from requirements, examples, fixtures, or golden data

Effort: S-M Action: STRENGTHEN_ORACLE

3. Snapshot-Only Oracle

What: Snapshot tests without semantic assertions for the product behavior being protected

Detection:

• toMatchSnapshot, image snapshots, serialized JSON snapshots, or golden files with no nearby semantic assertion
• Snapshot updates are easy to approve without understanding the protected behavior

Layer 2:

• Skip if snapshot is the product contract and has review discipline documented
• Skip if paired with semantic assertions that verify critical fields or user-visible behavior

Severity: MEDIUM

Recommendation: Keep snapshots only as secondary evidence; add semantic assertions for key behavior or delete the snapshot-only test if it has no unique signal

Effort: S-M Action: STRENGTHEN_ORACLE or DELETE_WEAK_ORACLE

4. Over-Mocking

What: Test mocks the system under test or internal collaborators so aggressively that the real behavior is not exercised

Detection:

• Mocked function is also the function under test
• Most assertions verify mocks instead of product-visible output or state
• Internal methods are stubbed to the exact values later asserted

Layer 2:

• Boundary mocks are valid when they isolate external systems and the test still asserts local product behavior
• Do not duplicate isolation findings from ln-635; this check is about proof strength, not dependency control

Severity: HIGH when the test appears to cover critical logic but proves only mocks, MEDIUM otherwise

Recommendation: Exercise real local behavior and mock only external boundaries; assert the product contract instead of implementation calls

Effort: M Action: STRENGTHEN_ORACLE

5. Mutation-Style Evidence

What: Use mutation reports or equivalent evidence to detect tests that do not fail when production behavior changes

Detection:

• If mutation reports exist, map surviving mutants to tests/modules with weak assertions
• If reports do not exist, identify critical modules whose tests already show weak-oracle signals and may benefit from mutation checks

Severity: LOW for missing mutation evidence alone, MEDIUM when surviving mutants confirm weak assertions

Recommendation: Add mutation-style evidence for critical local logic only; do not require mutation testing for the whole suite

Effort: M-L Action: ADD_MUTATION_EVIDENCE

Scoring Algorithm

MANDATORY READ: Load references/audit_scoring.md.

Severity mapping:

• No oracle for critical behavior, over-mocking critical logic -> HIGH
• Weak semantic assertions, snapshot-only tests, mutation survivors -> MEDIUM
• Missing mutation evidence for critical modules with weak-oracle signals -> LOW

Output Format

MANDATORY READ: Load references/templates/audit_worker_report_template.md.

Write JSON summary per references/audit_summary_contract.md. In managed mode the caller passes both runId and summaryArtifactPath; in standalone mode the worker generates its own run-scoped artifact path per shared contract.

Write report to {output_dir}/ln-638--global.md with category: "Oracle Effectiveness" and checks: assertion_strength, meaningful_oracle, snapshot_oracle, over_mocking, mutation_style_evidence.

Return summary per references/audit_summary_contract.md.

When summaryArtifactPath is absent, write the standalone runtime summary under .hex-skills/runtime-artifacts/runs/{run_id}/evaluation-worker/{worker}--{identifier}.json and optionally echo the same summary in structured output.

Report written: .hex-skills/runtime-artifacts/runs/{run_id}/audit-report/ln-638--global.md
Score: X.X/10 | Issues: N (C:N H:N M:N L:N)

Critical Rules

Apply the already-loaded references/audit_worker_core_contract.md.

• Do not auto-fix: Report only
• Unique angle: Audit only oracle/assertion effectiveness. Do not evaluate product-vs-platform focus, E2E journey value, portfolio value, missing coverage, trustworthiness, manual evidence, or structure.
• No mutation mandate: Do not require mutation testing unless evidence already exists or critical modules have weak oracles.
• Action required: Every finding uses one of STRENGTHEN_ORACLE, DELETE_WEAK_ORACLE, or ADD_MUTATION_EVIDENCE.
• Effort realism: S = <1h, M = 1-4h, L = >4h

Definition of Done

Apply the already-loaded references/audit_worker_core_contract.md.

• contextStore parsed successfully (including output_dir)
• Assertion strength checked
• Meaningful oracle quality checked
• Snapshot-only oracle candidates checked
• Over-mocking checked for proof strength
• Mutation-style evidence used when available
• Layer 2 context analysis applied
• Findings collected with severity, location, effort, action, recommendation
• Score calculated using penalty algorithm
• Report written to {output_dir}/ln-638--global.md (atomic single Write call)
• Summary written per contract

Version: 1.0.0 Last Updated: 2026-05-09