Add test about attempting to cast an uncastable userstream

Author: Girgias

tests/output/stream_isatty_non_castable_userwrapper.phpt

@@ -0,0 +1,25 @@
+--TEST--
+Non castable user-space streams (stream_cast())
+--FILE--
+<?php
+class test_wrapper {
+    public $context;
+    public $return_value;
+    function stream_open($path, $mode, $openedpath) {
+        return true;
+    }
+    function stream_eof() {
+        return false;
+    }
+}
+
+stream_wrapper_register('test', 'test_wrapper');
+$fd = fopen("test://foo","r");
+var_dump(stream_isatty($fd));
+
+?>
+--EXPECTF--
+Warning: stream_isatty(): test_wrapper::stream_cast is not implemented! in %s on line %d
+
+Warning: stream_isatty(): test_wrapper::stream_cast is not implemented! in %s on line %d
+bool(false)