diff --git a/tests/unit/Framework/MockObject/ReturnValueGeneratorTest.php b/tests/unit/Framework/MockObject/ReturnValueGeneratorTest.php
index 6529d5854a0..c65c1a0af53 100644
--- a/tests/unit/Framework/MockObject/ReturnValueGeneratorTest.php
+++ b/tests/unit/Framework/MockObject/ReturnValueGeneratorTest.php
@@ -120,17 +120,35 @@ public function test_Generates_callable_for_Closure(): void
 
     public function test_Generates_Generator_for_Generator(): void
     {
-        $this->assertInstanceOf(Generator::class, $this->generate('Generator'));
+        $value = $this->generate('Generator');
+
+        $this->assertInstanceOf(Generator::class, $value);
+
+        foreach ($value as $element) {
+            $this->assertSame([], $element);
+        }
     }
 
     public function test_Generates_Generator_for_Traversable(): void
     {
-        $this->assertInstanceOf(Generator::class, $this->generate('Traversable'));
+        $value = $this->generate('Traversable');
+
+        $this->assertInstanceOf(Generator::class, $value);
+
+        foreach ($value as $element) {
+            $this->assertSame([], $element);
+        }
     }
 
     public function test_Generates_Generator_for_iterable(): void
     {
-        $this->assertInstanceOf(Generator::class, $this->generate('iterable'));
+        $value = $this->generate('iterable');
+
+        $this->assertInstanceOf(Generator::class, $value);
+
+        foreach ($value as $element) {
+            $this->assertSame([], $element);
+        }
     }
 
     public function test_Generates_test_stub_for_class_or_interface_name(): void