test(auth): add test-only auth instance with testUtils plugin and initial tests

lib/auth/test.ts

@@ -0,0 +1,21 @@
+import { betterAuth } from "better-auth"
+import { testUtils } from "better-auth/plugins"
+import { drizzleAdapter } from "@better-auth/drizzle-adapter"
+import { db } from "@/lib/db/index"
+
+export const testAuth = betterAuth({
+  database: drizzleAdapter(db, {
+    provider: "pg",
+  }),
+  plugins: [
+    testUtils({ captureOTP: true }),
+  ],
+  emailAndPassword: {
+    enabled: true,
+  },
+})
+
+export async function getTestHelpers() {
+  const ctx = await testAuth.$context
+  return ctx.test
+}