test: add telemetry header test

src/telemetry.test.ts

@@ -0,0 +1,62 @@
+#!/usr/bin/env bun
+
+import { describe, it, expect, beforeEach, afterEach, spyOn } from "bun:test";
+import { config } from "./config";
+import { HttpClient } from "./http";
+import { telemetry } from "./telemetry";
+import { VERSION } from "./version";
+
+let fetchSpy: ReturnType<typeof spyOn>;
+let capturedHeaders: Record<string, string> = {};
+
+beforeEach(() => {
+  capturedHeaders = {};
+  fetchSpy = spyOn(globalThis, "fetch").mockImplementation(async (_url, init) => {
+    capturedHeaders = (init?.headers ?? {}) as Record<string, string>;
+    return new Response("{}", { status: 200, headers: { "content-type": "application/json" } });
+  });
+});
+
+afterEach(() => {
+  fetchSpy.mockRestore();
+  config.disableTelemetry = false;
+});
+
+describe("telemetry headers", () => {
+  it("sends Upstash-Telemetry-* headers by default", async () => {
+    const client = new HttpClient({ baseUrl: "https://api.upstash.com" });
+    await client.get("v2/test");
+
+    expect(capturedHeaders["Upstash-Telemetry-Runtime"]).toBe(telemetry.runtime);
+    expect(capturedHeaders["Upstash-Telemetry-Platform"]).toBe(telemetry.platform);
+    expect(capturedHeaders["Upstash-Telemetry-Sdk"]).toBe(telemetry.sdk);
+  });
+
+  it("includes the package version in the Sdk header", async () => {
+    const client = new HttpClient({ baseUrl: "https://api.upstash.com" });
+    await client.get("v2/test");
+
+    expect(capturedHeaders["Upstash-Telemetry-Sdk"]).toBe(`@upstash/mcp-server@${VERSION}`);
+  });
+
+  it("omits telemetry headers when disableTelemetry is true", async () => {
+    config.disableTelemetry = true;
+    const client = new HttpClient({ baseUrl: "https://api.upstash.com" });
+    await client.get("v2/test");
+
+    expect(capturedHeaders["Upstash-Telemetry-Runtime"]).toBeUndefined();
+    expect(capturedHeaders["Upstash-Telemetry-Platform"]).toBeUndefined();
+    expect(capturedHeaders["Upstash-Telemetry-Sdk"]).toBeUndefined();
+  });
+});
+
+describe("telemetry values", () => {
+  it("detects the bun runtime", () => {
+    expect(telemetry.runtime).toMatch(/^bun@/);
+  });
+
+  it("reports a platform", () => {
+    expect(telemetry.platform).toBeTruthy();
+    expect(telemetry.platform).not.toBe("unknown");
+  });
+});