add test for #137

Author: m6w6

tests/issue137.phpt

@@ -0,0 +1,22 @@
+--TEST--
+Issue #137 (DateTime(Immutable) serialization doesn't work with php 7.4)
+--SKIPIF--
+<?php
+if (!extension_loaded("msgpack")) {
+   echo "skip"; 
+}
+--FILE--
+<?php
+var_dump(msgpack_unpack(msgpack_pack(new DatetimeImmutable)));
+?>
+OK
+--EXPECTF--
+object(DateTimeImmutable)#%d (3) {
+  ["date"]=>
+  string(26) "%d-%d-%d %d:%d:%f"
+  ["timezone_type"]=>
+  int(%d)
+  ["timezone"]=>
+  string(%d) "%s"
+}
+OK