tests: add some silly tests for path-util.c

src/shared/path-util.h

@@ -1,7 +1,6 @@
 /*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
 
-#ifndef foopathutilhfoo
-#define foopathutilhfoo
+#pragma once
 
 /***
   This file is part of systemd.
@@ -41,5 +40,3 @@ char **path_strv_canonicalize_uniq(char **l);
 
 int path_is_mount_point(const char *path, bool allow_symlink);
 int path_is_read_only_fs(const char *path);
-
-#endif