Fix tests

tests/Datagrid/DatagridTest.php

@@ -21,6 +21,7 @@
 use Symfony\Component\EventDispatcher\EventDispatcherInterface;
 use Symfony\Component\Form\Form;
 use Symfony\Component\Form\FormBuilder;
+use Symfony\Component\Form\FormBuilderInterface;
 use Symfony\Component\Form\FormFactoryInterface;
 
 class TestEntity
@@ -78,8 +79,10 @@ protected function setUp(): void
 
         $this->formBuilder
             ->method('add')
-            ->willReturnCallback(function ($name, $type, $options) use ($eventDispatcher, $formFactory): void {
+            ->willReturnCallback(function ($name, $type, $options) use ($eventDispatcher, $formFactory): FormBuilderInterface {
                 $this->formTypes[$name] = new FormBuilder($name, TestEntity::class, $eventDispatcher, $formFactory, $options);
+
+                return $this->formBuilder;
             });
 
         $form = $this->createMock(Form::class);