chore: import upstream snapshot with attribution

tests/unit/check-cognitive-complexity.test.ts

@@ -0,0 +1,79 @@
+import { test } from "node:test";
+import assert from "node:assert";
+import {
+  countCognitiveViolations,
+  evaluateCognitiveComplexity,
+} from "../../scripts/check/check-cognitive-complexity.mjs";
+
+// The .mjs module has no .d.ts; type the exported functions locally.
+type EslintReport = Array<{ messages: Array<{ ruleId: string }> }>;
+type CogComplexityVerdict = { regressed: boolean; improved: boolean };
+
+const count = countCognitiveViolations as (report: EslintReport) => number;
+const evaluate = evaluateCognitiveComplexity as (
+  current: number,
+  baseline: number
+) => CogComplexityVerdict;
+
+// --- countCognitiveViolations tests ---
+
+test("countCognitiveViolations: empty report returns 0", () => {
+  assert.equal(count([]), 0);
+});
+
+test("countCognitiveViolations: counts sonarjs/cognitive-complexity messages", () => {
+  const report: EslintReport = [
+    {
+      messages: [
+        { ruleId: "sonarjs/cognitive-complexity" },
+        { ruleId: "no-unused-vars" }, // should not count
+      ],
+    },
+    {
+      messages: [
+        { ruleId: "sonarjs/cognitive-complexity" },
+        { ruleId: "sonarjs/cognitive-complexity" },
+      ],
+    },
+  ];
+  assert.equal(count(report), 3);
+});
+
+test("countCognitiveViolations: no matching rules returns 0", () => {
+  const report: EslintReport = [{ messages: [{ ruleId: "no-eval" }, { ruleId: "no-console" }] }];
+  assert.equal(count(report), 0);
+});
+
+// --- evaluateCognitiveComplexity tests ---
+
+const FROZEN = 738;
+
+test("evaluateCognitiveComplexity: equal to baseline passes", () => {
+  const r = evaluate(FROZEN, FROZEN);
+  assert.equal(r.regressed, false);
+  assert.equal(r.improved, false);
+});
+
+test("evaluateCognitiveComplexity: one more violation is a regression", () => {
+  const r = evaluate(FROZEN + 1, FROZEN);
+  assert.equal(r.regressed, true);
+  assert.equal(r.improved, false);
+});
+
+test("evaluateCognitiveComplexity: fewer violations is an improvement", () => {
+  const r = evaluate(FROZEN - 1, FROZEN);
+  assert.equal(r.regressed, false);
+  assert.equal(r.improved, true);
+});
+
+test("evaluateCognitiveComplexity: zero violations is maximum improvement", () => {
+  const r = evaluate(0, FROZEN);
+  assert.equal(r.regressed, false);
+  assert.equal(r.improved, true);
+});
+
+test("evaluateCognitiveComplexity: strict integer comparison", () => {
+  assert.equal(evaluate(11, 10).regressed, true);
+  assert.equal(evaluate(10, 10).regressed, false);
+  assert.equal(evaluate(9, 10).regressed, false);
+});