feat: add extensive test suite

app/api/debug/handler.ts

@@ -0,0 +1,58 @@
+type DebugRuntime = {
+  bun: string;
+  node: string;
+  platform: string;
+  arch: string;
+  uptime: number;
+};
+
+type DebugHandlerDependencies = {
+  adminCheck: () => Promise<unknown>;
+  runtime: () => DebugRuntime;
+  memoryUsage: () => NodeJS.MemoryUsage;
+  probes: ReadonlyArray<{
+    name: string;
+    run: () => Promise<unknown>;
+  }>;
+  now?: () => number;
+};
+
+export function createDebugHandler({
+  adminCheck,
+  runtime,
+  memoryUsage,
+  probes,
+  now = () => performance.now(),
+}: DebugHandlerDependencies) {
+  return async function getDebugStatus() {
+    try {
+      if (!(await adminCheck())) return unauthorized();
+    } catch {
+      return unauthorized();
+    }
+
+    const results = await Promise.all(
+      probes.map(async ({ name, run }) => {
+        const started = now();
+
+        try {
+          await run();
+          return { name, ok: true, latencyMs: now() - started };
+        } catch {
+          return { name, ok: false, latencyMs: now() - started };
+        }
+      }),
+    );
+
+    return Response.json({
+      timestamp: new Date().toISOString(),
+      runtime: runtime(),
+      memory: memoryUsage(),
+      probes: results,
+    });
+  };
+}
+
+function unauthorized() {
+  return new Response("Unauthorized", { status: 401 });
+}