diff --git a/test.setup.ts b/test.setup.ts
index ed4e49d0..ce4bb11b 100644
--- a/test.setup.ts
+++ b/test.setup.ts
@@ -1,5 +1,7 @@
 import { webcrypto } from "crypto";
+import { TextEncoder, TextDecoder } from "util";
 
+Object.assign(globalThis, { TextEncoder, TextDecoder });
 Object.defineProperty(window, "CSS", { value: null });
 Object.defineProperty(window, "getComputedStyle", {
   value: () => {