fix(upload): replace non-existent isForbidden with isFilenameValid

IFilenameValidator has no isForbidden() method. The correct API is
isFilenameValid(string $filename): bool which returns true when the name
is acceptable – so the guard must negate it.

Also updated FileUploadHelperTest:
- testValidateUploadedFileSuccess: sets isFilenameValid→true explicitly
- testValidateUploadedFileWithForbiddenName: mocks isFilenameValid→false
  (PHPUnit will not let a per-test stub override a setUp stub, so the
  default was removed from setUp and added only to the success test)

Signed-off-by: Vitor Mattos <1079143+vitormattos@users.noreply.github.com>

Author: vitormattos

lib/Helper/FileUploadHelper.php

@@ -9,7 +9,7 @@
 namespace OCA\Libresign\Helper;
 
 use InvalidArgumentException;
-use OC\Files\FilenameValidator;
+use OCP\Files\IFilenameValidator;
 use OCP\IL10N;
 
 /**
@@ -18,6 +18,7 @@
 class FileUploadHelper {
 	public function __construct(
 		private IL10N $l10n,
+		private IFilenameValidator $filenameValidator,
 	) {
 	}
 
@@ -43,8 +44,7 @@ public function validateUploadedFile(array $uploadedFile): void {
 			throw new InvalidArgumentException($this->l10n->t('File is too big'));
 		}
 
-		$validator = \OCP\Server::get(FilenameValidator::class);
-		if ($validator->isForbidden($uploadedFile['tmp_name'])) {
+		if (!$this->filenameValidator->isFilenameValid(basename($uploadedFile['tmp_name']))) {
 			@unlink($uploadedFile['tmp_name']);
 			throw new InvalidArgumentException($this->l10n->t('Invalid file provided'));
 		}

tests/php/Unit/Helper/FileUploadHelperTest.php

@@ -16,13 +16,15 @@ function is_uploaded_file($filename) {
 
 use InvalidArgumentException;
 use OCA\Libresign\Helper\FileUploadHelper;
+use OCP\Files\IFilenameValidator;
 use OCP\IL10N;
 use PHPUnit\Framework\MockObject\MockObject;
 use PHPUnit\Framework\TestCase;
 
 class FileUploadHelperTest extends TestCase {
 	private FileUploadHelper $helper;
 	private IL10N&MockObject $l10n;
+	private IFilenameValidator&MockObject $filenameValidator;
 	private string $tempFile;
 
 	protected function setUp(): void {
@@ -32,7 +34,9 @@ protected function setUp(): void {
 		$this->l10n->method('t')
 			->willReturnCallback(fn ($text) => $text);
 
-		$this->helper = new FileUploadHelper($this->l10n);
+		$this->filenameValidator = $this->createMock(IFilenameValidator::class);
+
+		$this->helper = new FileUploadHelper($this->l10n, $this->filenameValidator);
 
 		$this->tempFile = tempnam(sys_get_temp_dir(), 'upload_test_');
 		file_put_contents($this->tempFile, 'test content');
@@ -46,6 +50,8 @@ protected function tearDown(): void {
 	}
 
 	public function testValidateUploadedFileSuccess(): void {
+		$this->filenameValidator->method('isFilenameValid')->willReturn(true);
+
 		$uploadedFile = [
 			'tmp_name' => $this->tempFile,
 			'error' => UPLOAD_ERR_OK,
@@ -131,32 +137,21 @@ public function testReadUploadedFileNotReadable(): void {
 	}
 
 	public function testValidateUploadedFileWithForbiddenName(): void {
-		$forbiddenFile = sys_get_temp_dir() . '/test<file>.txt';
-
-		if (@file_put_contents($forbiddenFile, 'test') === false) {
-			$this->markTestSkipped('Cannot create file with forbidden characters on this OS');
-			return;
-		}
+		$this->filenameValidator->method('isFilenameValid')->willReturn(false);
 
 		$uploadedFile = [
-			'tmp_name' => $forbiddenFile,
+			'tmp_name' => $this->tempFile,
 			'error' => UPLOAD_ERR_OK,
-			'size' => filesize($forbiddenFile),
+			'size' => filesize($this->tempFile),
 		];
 
-		$exceptionThrown = false;
+		$this->expectException(InvalidArgumentException::class);
+		$this->expectExceptionMessage('Invalid file provided');
+
 		try {
 			$this->helper->validateUploadedFile($uploadedFile);
-		} catch (InvalidArgumentException $e) {
-			$exceptionThrown = true;
-			$this->assertEquals('Invalid file provided', $e->getMessage());
-			$this->assertFalse(file_exists($forbiddenFile), 'File should be deleted after validation fails');
 		} finally {
-			@unlink($forbiddenFile);
-		}
-
-		if (!$exceptionThrown) {
-			$this->markTestSkipped('FilenameValidator does not consider this filename as forbidden on this OS');
+			$this->assertFalse(file_exists($this->tempFile), 'File should be deleted after validation fails');
 		}
 	}
 }