diff --git a/rollup.config.js b/rollup.config.js
index c1143978..985580c0 100644
--- a/rollup.config.js
+++ b/rollup.config.js
@@ -93,7 +93,7 @@ export default Object.assign([
   {
     input: 'test/unittests.js',
     output: [
-      { file: 'test/lib/unittests-bundle.js', format: 'es', sourcemap: true },
+      { file: 'test/lib/unittests-bundle.js', format: 'es', intro, sourcemap: true },
     ],
     inlineDynamicImports: true,
     plugins: [
diff --git a/test/unittests.js b/test/unittests.js
index 91f9a8fb..1296da9c 100644
--- a/test/unittests.js
+++ b/test/unittests.js
@@ -1,3 +1,5 @@
+(typeof window !== 'undefined' ? window : global).globalThis = (typeof window !== 'undefined' ? window : global);
+
 (typeof window !== 'undefined' ? window : global).resolves = function(val) {
   return new Promise(function(res) { res(val); });
 };