diff --git a/Tests/LibWeb/Text/input/get-bounding-client-rect.html b/Tests/LibWeb/Text/input/get-bounding-client-rect.html
index eb7da97d5d3..89d78cf6dcb 100644
--- a/Tests/LibWeb/Text/input/get-bounding-client-rect.html
+++ b/Tests/LibWeb/Text/input/get-bounding-client-rect.html
@@ -13,12 +13,10 @@
 <script src="include.js"></script>
 <script>
     test(() => {
-        const rect = document.getElementById("box").getBoundingClientRect();
-        println(JSON.stringify(rect));
-    });
+        const box_rect = document.getElementById("box").getBoundingClientRect();
+        println(JSON.stringify(box_rect));
 
-    test(() => {
-        const rect = document.getElementById("inline").getBoundingClientRect();
-        println(JSON.stringify(rect));
+        const inline_rect = document.getElementById("inline").getBoundingClientRect();
+        println(JSON.stringify(inline_rect));
     });
 </script>
diff --git a/Tests/LibWeb/Text/input/include.js b/Tests/LibWeb/Text/input/include.js
index 41d9ba674b6..ee1e976412a 100644
--- a/Tests/LibWeb/Text/input/include.js
+++ b/Tests/LibWeb/Text/input/include.js
@@ -1,4 +1,11 @@
 var __outputElement = null;
+let __alreadyCalledTest = false;
+function __preventMultipleTestFunctions() {
+    if (__alreadyCalledTest) {
+        throw new Error("You must only call test() or asyncTest() once per page");
+    }
+    __alreadyCalledTest = true;
+}
 
 if (globalThis.internals === undefined) {
     internals = {
@@ -17,6 +24,7 @@ document.addEventListener("DOMContentLoaded", function () {
 });
 
 function test(f) {
+    __preventMultipleTestFunctions();
     document.addEventListener("DOMContentLoaded", f);
     window.addEventListener("load", () => {
         internals.signalTextTestIsDone();
@@ -24,7 +32,10 @@ function test(f) {
 }
 
 function asyncTest(f) {
-    const done = () => internals.signalTextTestIsDone();
+    const done = () => {
+        __preventMultipleTestFunctions();
+        internals.signalTextTestIsDone();
+    };
     document.addEventListener("DOMContentLoaded", () => {
         f(done);
     });