Add PDF signature zone availability checks

Introduce `PDFSignatureZoneAvailable` service to check available PDF signature zones. Updated `WorkflowAddSignatureController` to use the new service. Added unit tests to verify the correctness of the functionality.

src/Bundle/ChillMainBundle/Tests/Controller/WorkflowAddSignatureControllerTest.php

@@ -0,0 +1,72 @@
+<?php
+
+declare(strict_types=1);
+
+/*
+ * Chill is a software for social workers
+ *
+ * For the full copyright and license information, please view
+ * the LICENSE file that was distributed with this source code.
+ */
+
+namespace Chill\MainBundle\Tests\Controller;
+
+use Chill\DocStoreBundle\Entity\StoredObject;
+use Chill\DocStoreBundle\Service\Signature\PDFPage;
+use Chill\DocStoreBundle\Service\Signature\PDFSignatureZone;
+use Chill\DocStoreBundle\Service\Signature\PDFSignatureZoneAvailable;
+use Chill\MainBundle\Controller\WorkflowAddSignatureController;
+use Chill\MainBundle\Entity\User;
+use Chill\MainBundle\Entity\Workflow\EntityWorkflow;
+use Chill\MainBundle\Workflow\EntityWorkflowManager;
+use Chill\MainBundle\Workflow\WorkflowTransitionContextDTO;
+use Chill\PersonBundle\Entity\Person;
+use PHPUnit\Framework\TestCase;
+use Symfony\Component\HttpFoundation\Request;
+use Symfony\Component\Serializer\Normalizer\NormalizerInterface;
+use Twig\Environment;
+
+/**
+ * @internal
+ *
+ * @coversNothing
+ */
+class WorkflowAddSignatureControllerTest extends TestCase
+{
+    public function testAddSignature(): void
+    {
+        $storedObject = new StoredObject();
+        $entityWorkflow = new EntityWorkflow();
+        $stepTransition = new WorkflowTransitionContextDTO($entityWorkflow);
+        $stepTransition->futurePersonSignatures[] = new Person();
+        $entityWorkflow->setStep('step_signature', $stepTransition, 'to_signature', new \DateTimeImmutable('now'), new User());
+
+        $signature = $entityWorkflow->getCurrentStep()->getSignatures()->first();
+
+        $entityWorkflowManager = $this->createMock(EntityWorkflowManager::class);
+        $entityWorkflowManager->method('getAssociatedStoredObject')
+            ->with($entityWorkflow)
+            ->willReturn($storedObject);
+
+        $pdfSignatureZoneAvailable = $this->createMock(PDFSignatureZoneAvailable::class);
+        $pdfSignatureZoneAvailable->method('getAvailableSignatureZones')->withAnyParameters()
+            ->willReturn([
+                new PDFSignatureZone(1, 0.0, 0.0, 100, 100, new PDFPage(1, 500.0, 500.0)),
+            ]);
+
+        $normalizer = $this->createMock(NormalizerInterface::class);
+        $normalizer->method('normalize')->withAnyParameters()
+            ->willReturn([]);
+
+        $twig = $this->createMock(Environment::class);
+        $twig->method('render')->with('@ChillMain/Workflow/_signature_sign.html.twig', $this->isType('array'))
+            ->willReturn('ok');
+
+        $controller = new WorkflowAddSignatureController($entityWorkflowManager, $pdfSignatureZoneAvailable, $normalizer, $twig);
+
+        $actual = $controller($signature, new Request());
+
+        self::assertEquals(200, $actual->getStatusCode());
+        self::assertEquals('ok', $actual->getContent());
+    }
+}