ext/gd/imagefilter: Add test case for manual ZPP

Author: Girgias

ext/gd/tests/imagefilter_error1.phpt

@@ -14,6 +14,12 @@ try {
 } catch (TypeError $e) {
     echo $e->getMessage(), "\n";
 }
+try {
+    var_dump(imagefilter(20, 1));
+} catch (TypeError $e) {
+    echo $e->getMessage(), "\n";
+}
 ?>
 --EXPECT--
 Wrong parameter count for imagefilter()
+imagefilter(): Argument #1 ($image) must be of type GdImage, int given