From 07bb8e5bf6b31a7c73c260fdf52d4102559dbeab Mon Sep 17 00:00:00 2001
From: ryder777777 <ryder777777@users.noreply.github.com>
Date: Tue, 20 Oct 2026 22:04:54 +0000
Subject: [PATCH] feat(analytics): add visual-regression-testing-for-key helper
 and unit tests (#108)

---
 .../visual-regression-testing-for-key.test.ts | 14 +++++++
 .../visual-regression-testing-for-key.ts      | 40 +++++++++++++++++++
 2 files changed, 54 insertions(+)
 create mode 100644 lib/analytics/__tests__/visual-regression-testing-for-key.test.ts
 create mode 100644 lib/analytics/visual-regression-testing-for-key.ts

diff --git a/lib/analytics/__tests__/visual-regression-testing-for-key.test.ts b/lib/analytics/__tests__/visual-regression-testing-for-key.test.ts
new file mode 100644
index 0000000..6a7917f
--- /dev/null
+++ b/lib/analytics/__tests__/visual-regression-testing-for-key.test.ts
@@ -0,0 +1,14 @@
+import { describe, expect, it } from "vitest";
+import { evaluateVisualRegressionTestingForKey } from "../visual-regression-testing-for-key";
+
+describe("evaluateVisualRegressionTestingForKey", () => {
+  it("evaluates nominal, elevated, and critical thresholds deterministically", () => {
+    expect(evaluateVisualRegressionTestingForKey({ contextId: "ctx-1", primaryMetric: 15, secondaryMetric: 10, limitThreshold: 100 }).status).toBe("nominal");
+    expect(evaluateVisualRegressionTestingForKey({ contextId: "ctx-2", primaryMetric: 40, secondaryMetric: 20 }).status).toBe("elevated");
+    expect(evaluateVisualRegressionTestingForKey({ contextId: "ctx-3", primaryMetric: 70, secondaryMetric: 25, limitThreshold: 100 }).status).toBe("critical");
+  });
+
+  it("rejects blank contextId", () => {
+    expect(() => evaluateVisualRegressionTestingForKey({ contextId: "   ", primaryMetric: 1, secondaryMetric: 1 })).toThrow(/contextId is required/);
+  });
+});
diff --git a/lib/analytics/visual-regression-testing-for-key.ts b/lib/analytics/visual-regression-testing-for-key.ts
new file mode 100644
index 0000000..f2831fe
--- /dev/null
+++ b/lib/analytics/visual-regression-testing-for-key.ts
@@ -0,0 +1,40 @@
+export interface VisualRegressionTestingForKeySummaryInput {
+  contextId: string;
+  primaryMetric: number;
+  secondaryMetric: number;
+  limitThreshold?: number;
+}
+
+export interface VisualRegressionTestingForKeySummary {
+  contextId: string;
+  primaryMetric: number;
+  secondaryMetric: number;
+  scoreBps: number;
+  status: "nominal" | "elevated" | "critical";
+}
+
+export function evaluateVisualRegressionTestingForKey(input: VisualRegressionTestingForKeySummaryInput): VisualRegressionTestingForKeySummary {
+  const contextId = input.contextId.trim();
+  if (!contextId) {
+    throw new Error("evaluateVisualRegressionTestingForKey: contextId is required");
+  }
+  const primaryMetric = Math.max(0, Math.trunc(input.primaryMetric));
+  const secondaryMetric = Math.max(0, Math.trunc(input.secondaryMetric));
+  const limit = Math.max(1, Math.trunc(input.limitThreshold ?? 100));
+
+  const scoreBps = Math.min(10000, Math.round(((primaryMetric + secondaryMetric) * 10000) / limit));
+  let status: "nominal" | "elevated" | "critical" = "nominal";
+  if (scoreBps >= 8500) {
+    status = "critical";
+  } else if (scoreBps >= 5000) {
+    status = "elevated";
+  }
+
+  return {
+    contextId,
+    primaryMetric,
+    secondaryMetric,
+    scoreBps,
+    status,
+  };
+}