chore: import upstream snapshot with attribution

scripts/check/test-report-summary.mjs

@@ -0,0 +1,110 @@
+import { existsSync, readFileSync, writeFileSync } from "node:fs";
+import path from "node:path";
+
+function getArg(name, fallbackValue = "") {
+  const index = process.argv.indexOf(name);
+  if (index === -1 || index === process.argv.length - 1) {
+    return fallbackValue;
+  }
+  return process.argv[index + 1];
+}
+
+function formatPercent(value) {
+  return `${Number(value ?? 0).toFixed(2)}%`;
+}
+
+function parseThreshold(name, fallbackValue) {
+  const rawValue = getArg(name, fallbackValue);
+  const value = Number(rawValue);
+  if (!Number.isFinite(value)) {
+    console.error(`Invalid coverage threshold for ${name}: ${rawValue}`);
+    process.exit(1);
+  }
+  return value;
+}
+
+const inputPath = getArg("--input", "coverage/coverage-summary.json");
+const outputPath = getArg("--output", "");
+const hasGlobalThreshold = process.argv.includes("--threshold");
+const defaultThreshold = parseThreshold("--threshold", "75");
+
+if (!existsSync(inputPath)) {
+  console.error(`Coverage summary file not found: ${inputPath}`);
+  process.exit(1);
+}
+
+const summary = JSON.parse(readFileSync(inputPath, "utf8"));
+const cwd = process.cwd();
+const metrics = [
+  ["lines", "Lines"],
+  ["statements", "Statements"],
+  ["functions", "Functions"],
+  ["branches", "Branches"],
+];
+const thresholds = Object.fromEntries(
+  metrics.map(([metric]) => {
+    const fallback = metric === "branches" && !hasGlobalThreshold ? "70" : String(defaultThreshold);
+    return [metric, parseThreshold(`--${metric}`, fallback)];
+  })
+);
+
+const total = summary.total ?? {};
+const gatePassed = metrics.every(([metric]) => (total[metric]?.pct ?? 0) >= thresholds[metric]);
+
+const files = Object.entries(summary)
+  .filter(([name]) => name !== "total" && /\.(?:[cm]?[jt]sx?)$/.test(name))
+  .map(([name, stats]) => {
+    const relativeName = path.relative(cwd, name);
+    const totalLines = stats.lines?.total ?? 0;
+    const coveredLines = stats.lines?.covered ?? 0;
+
+    return {
+      name: relativeName,
+      lines: stats.lines?.pct ?? 0,
+      branches: stats.branches?.pct ?? 0,
+      functions: stats.functions?.pct ?? 0,
+      missingLines: Math.max(totalLines - coveredLines, 0),
+    };
+  })
+  .sort((left, right) => {
+    if (left.lines !== right.lines) return left.lines - right.lines;
+    if (left.branches !== right.branches) return left.branches - right.branches;
+    return right.missingLines - left.missingLines;
+  })
+  .slice(0, 15);
+
+const report = [
+  "# Coverage Report",
+  "",
+  `Gate: ${gatePassed ? "PASS" : "FAIL"} at configured metric minimums.`,
+  "",
+  "## Totals",
+  "",
+  "| Metric | Covered | Total | Percent | Threshold | Status |",
+  "| --- | ---: | ---: | ---: | ---: | --- |",
+  ...metrics.map(([metric, label]) => {
+    const covered = total[metric]?.covered ?? 0;
+    const totalCount = total[metric]?.total ?? 0;
+    const pct = total[metric]?.pct ?? 0;
+    const threshold = thresholds[metric];
+    const status = pct >= threshold ? "PASS" : "FAIL";
+    return `| ${label} | ${covered} | ${totalCount} | ${formatPercent(pct)} | ${threshold}% | ${status} |`;
+  }),
+  "",
+  "## Lowest Coverage Files",
+  "",
+  "| File | Lines | Branches | Functions | Missing Lines |",
+  "| --- | ---: | ---: | ---: | ---: |",
+  ...files.map(
+    (entry) =>
+      `| \`${entry.name}\` | ${formatPercent(entry.lines)} | ${formatPercent(entry.branches)} | ${formatPercent(entry.functions)} | ${entry.missingLines} |`
+  ),
+];
+
+const reportContent = `${report.join("\n")}\n`;
+
+if (outputPath) {
+  writeFileSync(outputPath, reportContent);
+} else {
+  process.stdout.write(reportContent);
+}