Added response test and did some sanitizing

flight/net/Response.php

@@ -484,7 +484,7 @@ class Response
      * Downloads a file.
      *
      * @param string $filePath The path to the file to be downloaded.
-     * @param string $fileName The name the downloaded file should have. If not provided, the name of the file on disk will be used.
+     * @param string $fileName The name the downloaded file should have. If not provided or is an empty string, the name of the file on disk will be used.
      *
      * @throws Exception If the file cannot be found.
      *
@@ -501,6 +501,8 @@ class Response
         $mimeType = mime_content_type($filePath);
         $mimeType = $mimeType !== false ? $mimeType : 'application/octet-stream';
 
+        // Sanitize filename to prevent header injection
+        $fileName = str_replace(["\r", "\n", '"'], '', $fileName);
         if ($fileName === '') {
             $fileName = basename($filePath);
         }

tests/EngineTest.php

@@ -1086,11 +1086,13 @@ class EngineTest extends TestCase
         // doing this so we can overwrite some parts of the response
         $engine->getLoader()->register('response', function () {
             return new class extends Response {
+				public $headersSent = [];
                 public function setRealHeader(
                     string $header_string,
                     bool $replace = true,
                     int $response_code = 0
                 ): self {
+					$this->headersSent[] = $header_string;
                     return $this;
                 }
             };
@@ -1100,6 +1102,37 @@ class EngineTest extends TestCase
 		$streamPath = stream_get_meta_data($tmpfile)['uri'];
 		$this->expectOutputString('I am a teapot');
         $engine->download($streamPath);
+		$this->assertContains('Content-Disposition: attachment; filename="'.basename($streamPath).'"', $engine->response()->headersSent);
+    }
+
+	public function testDownloadWithDefaultFileName(): void
+    {
+        $engine = new class extends Engine {
+            public function getLoader()
+            {
+                return $this->loader;
+            }
+        };
+        // doing this so we can overwrite some parts of the response
+        $engine->getLoader()->register('response', function () {
+            return new class extends Response {
+				public $headersSent = [];
+                public function setRealHeader(
+                    string $header_string,
+                    bool $replace = true,
+                    int $response_code = 0
+                ): self {
+					$this->headersSent[] = $header_string;
+                    return $this;
+                }
+            };
+        });
+		$tmpfile = tmpfile();
+		fwrite($tmpfile, 'I am a teapot');
+		$streamPath = stream_get_meta_data($tmpfile)['uri'];
+		$this->expectOutputString('I am a teapot');
+        $engine->download($streamPath, 'something.txt');
+		$this->assertContains('Content-Disposition: attachment; filename="something.txt"', $engine->response()->headersSent);
     }
 
 	public function testDownloadBadPath() {