diff --git a/app/core/src/test/java/stirling/software/SPDF/controller/api/RotationControllerTest.java b/app/core/src/test/java/stirling/software/SPDF/controller/api/RotationControllerTest.java
index 5677c26077..11073586e7 100644
--- a/app/core/src/test/java/stirling/software/SPDF/controller/api/RotationControllerTest.java
+++ b/app/core/src/test/java/stirling/software/SPDF/controller/api/RotationControllerTest.java
@@ -1,6 +1,7 @@
 package stirling.software.SPDF.controller.api;
 
 import static org.junit.jupiter.api.Assertions.*;
+import static org.mockito.ArgumentMatchers.any;
 import static org.mockito.ArgumentMatchers.anyString;
 import static org.mockito.Mockito.lenient;
 import static org.mockito.Mockito.mock;
@@ -14,19 +15,19 @@ import java.nio.file.Files;
 import org.apache.pdfbox.pdmodel.PDDocument;
 import org.apache.pdfbox.pdmodel.PDPage;
 import org.apache.pdfbox.pdmodel.PDPageTree;
+import org.jboss.resteasy.reactive.multipart.FileUpload;
 import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.Test;
 import org.junit.jupiter.api.extension.ExtendWith;
 import org.mockito.InjectMocks;
 import org.mockito.Mock;
 import org.mockito.junit.jupiter.MockitoExtension;
-import org.springframework.core.io.Resource;
-import org.springframework.http.MediaType;
-import org.springframework.http.ResponseEntity;
-import org.springframework.mock.web.MockMultipartFile;
+
+import jakarta.ws.rs.core.Response;
 
 import stirling.software.SPDF.model.api.general.RotatePDFRequest;
 import stirling.software.common.service.CustomPDFDocumentFactory;
+import stirling.software.common.testsupport.TestFileUploads;
 import stirling.software.common.util.TempFile;
 import stirling.software.common.util.TempFileManager;
 
@@ -56,48 +57,37 @@ public class RotationControllerTest {
 
     @Test
     public void testRotatePDF() throws IOException {
-        // Create a mock file
-        MockMultipartFile mockFile =
-                new MockMultipartFile(
-                        "file", "test.pdf", MediaType.APPLICATION_PDF_VALUE, new byte[] {1, 2, 3});
-        RotatePDFRequest request = new RotatePDFRequest();
-        request.setFileInput(mockFile);
-        request.setAngle(90);
+        // The controller binds @RestForm FileUpload and rebuilds the RotatePDFRequest internally.
+        FileUpload fileUpload = TestFileUploads.pdf(new byte[] {1, 2, 3});
 
         PDDocument mockDocument = mock(PDDocument.class);
         PDPageTree mockPages = mock(PDPageTree.class);
         PDPage mockPage = mock(PDPage.class);
 
-        when(pdfDocumentFactory.load(request)).thenReturn(mockDocument);
+        when(pdfDocumentFactory.load(any(RotatePDFRequest.class))).thenReturn(mockDocument);
         when(mockDocument.getPages()).thenReturn(mockPages);
         when(mockPages.iterator())
                 .thenReturn(java.util.Collections.singletonList(mockPage).iterator());
         when(mockPage.getRotation()).thenReturn(0);
 
         // Act
-        ResponseEntity<Resource> response = rotationController.rotatePDF(request);
+        Response response = rotationController.rotatePDF(fileUpload, null, 90);
 
         // Assert
         verify(mockPage).setRotation(90);
         assertNotNull(response);
-        assertEquals(200, response.getStatusCode().value());
+        assertEquals(200, response.getStatus());
     }
 
     @Test
     public void testRotatePDFInvalidAngle() {
-        // Create a mock file
-        MockMultipartFile mockFile =
-                new MockMultipartFile(
-                        "file", "test.pdf", MediaType.APPLICATION_PDF_VALUE, new byte[] {1, 2, 3});
-        RotatePDFRequest request = new RotatePDFRequest();
-        request.setFileInput(mockFile);
-        request.setAngle(45); // Invalid angle
+        FileUpload fileUpload = TestFileUploads.pdf(new byte[] {1, 2, 3});
 
-        // Act & Assert: Controller direkt aufrufen und Exception erwarten
+        // Act & Assert: call the controller directly and expect the validation exception.
         IllegalArgumentException exception =
                 assertThrows(
                         IllegalArgumentException.class,
-                        () -> rotationController.rotatePDF(request));
+                        () -> rotationController.rotatePDF(fileUpload, null, 45));
         assertEquals("Angle must be a multiple of 90", exception.getMessage());
     }
 }
diff --git a/app/core/src/test/java/stirling/software/common/testsupport/TestFileUploads.java b/app/core/src/test/java/stirling/software/common/testsupport/TestFileUploads.java
new file mode 100644
index 0000000000..56ca6875f1
--- /dev/null
+++ b/app/core/src/test/java/stirling/software/common/testsupport/TestFileUploads.java
@@ -0,0 +1,49 @@
+package stirling.software.common.testsupport;
+
+import static org.mockito.Mockito.lenient;
+import static org.mockito.Mockito.mock;
+
+import java.io.IOException;
+import java.io.UncheckedIOException;
+import java.nio.file.Files;
+import java.nio.file.Path;
+
+import org.jboss.resteasy.reactive.multipart.FileUpload;
+
+/**
+ * Builds RESTEasy Reactive {@link FileUpload} stubs for unit tests. The migrated controllers bind
+ * {@code @RestForm FileUpload} and wrap it via {@code FileUploadMultipartFile.of(...)}, which reads
+ * {@code uploadedFile()}/{@code fileName()}/{@code size()}. This backs the mock with a real temp
+ * file so those reads work whether or not the collaborator (e.g. {@code CustomPDFDocumentFactory})
+ * is itself mocked. All stubs are lenient so a test that never reaches a given accessor does not
+ * trip strict-stubbing.
+ */
+public final class TestFileUploads {
+
+    private TestFileUploads() {}
+
+    public static FileUpload of(byte[] content, String fileName, String contentType) {
+        try {
+            byte[] bytes = content == null ? new byte[0] : content;
+            String suffix = fileName == null ? "file" : fileName.replaceAll("[^a-zA-Z0-9._-]", "_");
+            Path tmp = Files.createTempFile("test-upload-", "-" + suffix);
+            tmp.toFile().deleteOnExit();
+            Files.write(tmp, bytes);
+
+            FileUpload upload = mock(FileUpload.class);
+            lenient().when(upload.uploadedFile()).thenReturn(tmp);
+            lenient().when(upload.filePath()).thenReturn(tmp);
+            lenient().when(upload.fileName()).thenReturn(fileName);
+            lenient().when(upload.contentType()).thenReturn(contentType);
+            lenient().when(upload.size()).thenReturn((long) bytes.length);
+            return upload;
+        } catch (IOException e) {
+            throw new UncheckedIOException(e);
+        }
+    }
+
+    /** Convenience for a PDF part named {@code test.pdf}. */
+    public static FileUpload pdf(byte[] content) {
+        return of(content, "test.pdf", "application/pdf");
+    }
+}