minor #30972 [Form] Fix tests (chalasr)

This PR was merged into the 3.4 branch.

Discussion
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[Form] Fix tests

| Q             | A
| ------------- | ---
| Branch?       | 3.4
| Bug fix?      | no
| New feature?  | no
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | yes
| Fixed tickets | n/a
| License       | MIT
| Doc PR        | n/a

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Commits
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35418be8c4 [Form] Fix tests

src/Symfony/Component/Form/Tests/Extension/Core/Type/FileTypeTest.php

@@ -11,16 +11,26 @@
 
 namespace Symfony\Component\Form\Tests\Extension\Core\Type;
 
+use Symfony\Component\Form\Extension\Core\CoreExtension;
 use Symfony\Component\Form\Extension\HttpFoundation\HttpFoundationRequestHandler;
 use Symfony\Component\Form\NativeRequestHandler;
 use Symfony\Component\Form\RequestHandlerInterface;
 use Symfony\Component\HttpFoundation\File\File;
 use Symfony\Component\HttpFoundation\File\UploadedFile;
+use Symfony\Component\Translation\TranslatorInterface;
 
 class FileTypeTest extends BaseTypeTest
 {
     const TESTED_TYPE = 'Symfony\Component\Form\Extension\Core\Type\FileType';
 
+    protected function getExtensions()
+    {
+        $translator = $this->createMock(TranslatorInterface::class);
+        $translator->expects($this->any())->method('trans')->willReturnArgument(0);
+
+        return array_merge(parent::getExtensions(), [new CoreExtension(null, null, $translator)]);
+    }
+
     // https://github.com/symfony/symfony/pull/5028
     public function testSetData()
     {