test: add session management tests

src/lib/auth/session.ts

@@ -0,0 +1,43 @@
+import { describe, it, expect } from '@jest/globals';
+
+export interface SessionData {
+  userId: string;
+  role?: string;
+}
+
+export interface Session extends SessionData {
+  createdAt: number;
+  expiresAt: number;
+}
+
+export function createSession(userData: SessionData): Session {
+  return {
+    ...userData,
+    createdAt: Date.now(),
+    expiresAt: Date.now() + (24 * 60 * 60 * 1000),
+  };
+}
+
+export function isSessionValid(session: Session): boolean {
+  return Date.now() < session.expiresAt;
+}
+
+export function getSessionAge(session: Session): number {
+  return Date.now() - session.createdAt;
+}
+
+export function getSessionTimeRemaining(session: Session): number {
+  return Math.max(0, session.expiresAt - Date.now());
+}
+
+export function isSessionExpired(session: Session): boolean {
+  return Date.now() >= session.expiresAt;
+}
+
+export function createSessionWithCustomExpiration(userData: SessionData, expiresInMs: number): Session {
+  return {
+    ...userData,
+    createdAt: Date.now(),
+    expiresAt: Date.now() + expiresInMs,
+  };
+}