test-utilities: Write the file name when creating a hierarchy

This will be used to confirm the content after renaming operations.

test/automated/displayless/test-utilities.c

@@ -82,6 +82,10 @@ create_hierarchy_from_template (const GStrv  hier,
         {
             g_autoptr (GFileOutputStream) stream = g_file_create (file, G_FILE_CREATE_NONE,
                                                                   NULL, NULL);
+            g_autofree gchar *name = g_file_get_basename (file);
+
+            g_output_stream_write_all (G_OUTPUT_STREAM (stream), name, strlen (name) + 1,
+                                       NULL, NULL, NULL);
         }
     }
 }