DLC: Test Coverage Analysis

Run the test suite, measure coverage, and create a GitHub issue for failures and coverage gaps.

Before running, read ../dlc/references/ISSUE-TEMPLATE.md now for the issue format, and read ../dlc/references/REPORT-FORMAT.md now for the findings data structure.

Step 1: Detect Test Framework

Scan for test configuration:

Config / Pattern	Framework	Coverage Tool
vitest.config.* / vite.config.* (with test)	Vitest	@vitest/coverage-v8
jest.config.* / package.json (with jest)	Jest	Built-in (--coverage)
pytest.ini / pyproject.toml (with pytest) / conftest.py	pytest	pytest-cov
Cargo.toml + tests/ dir	cargo test	cargo-tarpaulin or cargo-llvm-cov
go.mod + *_test.go files	go test	Built-in (-cover)
.rspec / Gemfile (with rspec)	RSpec	simplecov

Also detect test runner scripts in package.json or the project's task runner.

Step 2: Run Test Suite with Coverage

Execute tests with coverage enabled:

Select the tool based on availability (command -v) and detected framework, not exit codes — test runners exit non-zero when tests fail, which is a valid result to capture.

# Node.js (Vitest) — if vitest config detected
npx vitest run --coverage --reporter=json 2>/dev/null

# Node.js (Jest) — if jest config detected
npx jest --coverage --json 2>/dev/null

# Python
command -v pytest >/dev/null 2>&1 && pytest --cov=. --cov-report=json --tb=short 2>/dev/null

# Rust — select coverage tool by availability
if command -v cargo-tarpaulin >/dev/null 2>&1; then
  cargo tarpaulin --out json 2>/dev/null
elif command -v cargo-llvm-cov >/dev/null 2>&1; then
  cargo llvm-cov --json 2>/dev/null
fi

# Go
go test -cover -coverprofile=coverage.out -json ./... 2>/dev/null

# Custom test script — select runner by availability
if command -v bun >/dev/null 2>&1; then
  bun test 2>/dev/null
elif command -v npm >/dev/null 2>&1; then
  npm test 2>/dev/null
fi

Capture both:

• Test results: pass/fail status per test, failure messages
• Coverage metrics: line coverage %, branch coverage %, per-file breakdown

Step 3: Identify Coverage Gaps in Recent Changes

Focus on files changed recently (not just overall coverage):

# Files changed in last 5 commits
git diff --name-only HEAD~5..HEAD -- '*.ts' '*.js' '*.py' '*.go' '*.rs'

# Files changed vs main branch
git diff --name-only origin/main...HEAD

For each changed file:

1. Check if a corresponding test file exists
2. Check coverage percentage for that specific file
3. Flag files with < 80% coverage (or project-configured threshold)
4. Flag changed files with zero test coverage

Step 4: Classify Findings

Map results to the findings format from REPORT-FORMAT.md.

Severity mapping (reinforced here for defense-in-depth):

Finding Type	Severity
Test suite fails to run (config error, missing deps)	Critical
Failing tests (regressions)	High
Changed files with 0% coverage	High
Overall coverage below project threshold	Medium
Changed files with < 80% coverage	Medium
Missing test file for new module	Medium
Flaky tests (pass on retry)	Low
Coverage informational metrics	Info

Step 5: Create GitHub Issue

Read ../dlc/references/ISSUE-TEMPLATE.md now and format the issue body exactly as specified.

Critical format rules (reinforced here):

• Title: [DLC] Testing: {summary — e.g. "3 failures, 72% coverage"}
• Label: dlc-test
• Body must contain: Scan Metadata table, Findings Summary table (severity x count), Findings Detail grouped by severity, Recommended Actions, Raw Output in collapsed details
• Include a Coverage Summary subsection in the metadata:

### Coverage Summary

| Metric | Value | Target |
|--------|-------|--------|
| Line Coverage | {n}% | 80% |
| Branch Coverage | {n}% | 70% |
| Files with 0% | {n} | 0 |

REPO=$(gh repo view --json nameWithOwner -q .nameWithOwner)
BRANCH=$(git branch --show-current)
TIMESTAMP=$(date +%s)
BODY_FILE="/tmp/dlc-issue-${TIMESTAMP}.md"

gh issue create \
  --repo "$REPO" \
  --title "[DLC] Testing: {summary}" \
  --body-file "$BODY_FILE" \
  --label "dlc-test"

If issue creation fails, save draft to /tmp/dlc-draft-${TIMESTAMP}.md and print the path.

Step 6: Report

Test analysis complete.
  - Framework: {detected framework}
  - Tests: {passed} passed, {failed} failed, {skipped} skipped
  - Coverage: {line}% line, {branch}% branch
  - Changed files coverage: {n}/{total} above threshold
  - Issue: #{number} ({url})

If all tests pass and coverage is above threshold, skip issue creation and report: "All tests passing. Coverage meets threshold ({n}%)."