diff --git a/packages/wasm/test/fixtures/async.js b/packages/wasm/test/fixtures/async.js
index a3d4bb244..cd922fc47 100755
--- a/packages/wasm/test/fixtures/async.js
+++ b/packages/wasm/test/fixtures/async.js
@@ -1,5 +1,8 @@
 import fixture from './sample.wasm';
 
+// eslint-disable-next-line no-undef
+globalThis.atob = (str) => Buffer.from(str, 'base64').toString('binary');
+
 // eslint-disable-next-line no-undef
 result = (async () => {
   const module = await fixture();