diff --git a/lib/internal/test_runner/mock.js b/lib/internal/test_runner/mock.js
index 553082a1aa481b..a66e494d5d7d0a 100644
--- a/lib/internal/test_runner/mock.js
+++ b/lib/internal/test_runner/mock.js
@@ -134,9 +134,7 @@ class MockTracker {
   ) {
     validateStringOrSymbol(methodName, 'methodName');
     // In case object is a static class
-    if (typeof object === 'function') {
-      validateFunction(object, methodName);
-    } else {
+    if (typeof object !== 'function') {
       validateObject(object, 'object');
     }