1 files changed, 58 insertions, 0 deletions
diff --git a/tests/unit/includes/PhotodriverTest.php b/tests/unit/includes/PhotodriverTest.php
index 34dc058b7..db9883589 100644
--- a/tests/unit/includes/PhotodriverTest.php
+++ b/tests/unit/includes/PhotodriverTest.php
@@ -20,4 +20,62 @@ class PhotodriverTest extends UnitTestCase {
 		$photo = \photo_factory(file_get_contents('images/hz-16.png'), 'image/png');
 		$this->assertInstanceOf('Zotlabs\Photo\PhotoGd', $photo);
 	}
+
+	// Helper to create a temporary image file
+	private function createTempImage($type = 'jpeg'): string
+	{
+		$tmp = tempnam(sys_get_temp_dir(), 'img');
+		switch ($type) {
+			case 'png':
+				$im = imagecreatetruecolor(10, 10);
+				imagepng($im, $tmp);
+				imagedestroy($im);
+				break;
+			case 'jpeg':
+			default:
+				$im = imagecreatetruecolor(10, 10);
+				imagejpeg($im, $tmp);
+				imagedestroy($im);
+				break;
+		}
+		return $tmp;
+	}
+
+	public function testGuessImageTypeFromRawData()
+	{
+		$filename = 'irrelevant';
+		$data = [
+			'body' => file_get_contents($this->createTempImage('jpeg'))
+		];
+		$result = guess_image_type($filename, $data);
+		$this->assertEquals('image/jpeg', $result);
+	}
+
+	public function testGuessImageTypeFromLocalFile()
+	{
+		$file = $this->createTempImage('png');
+		$result = guess_image_type($file);
+		$this->assertEquals('image/png', $result);
+		unlink($file);
+	}
+
+	public function testGuessImageTypeFromHeaders()
+	{
+		$filename = 'irrelevant';
+		$data = [
+			'header' => "Content-Type: image/jpeg\nOther: value"
+		];
+		$result = guess_image_type($filename, $data);
+		$this->assertEquals('image/jpeg', $result);
+	}
+
+	public function testGuessImageTypeUnknownTypeReturnsNull()
+	{
+		$filename = 'not_an_image.txt';
+		$data = [
+			'body' => 'not an image'
+		];
+		$result = guess_image_type($filename, $data);
+		$this->assertNull($result);
+	}
 }