Instead of build dir, where it can clash when multiple tests runs are being done from the same build dir in parallel. Due to the way platform plugin argument parsing works we can't pass the full file name of the config, as on Windows this would include C:, which QGuiApplication will split into two, thinking they are two different platform plugin arguments. Instead we chdir into the temp dir, and create the file there, passing the file name as a relative path as before. Pick-to: 6.8 Change-Id: Ia4ea82280e35f4f52b7de74bbf53b2a48ecbaecd Reviewed-by: Morten Johan Sørvig <morten.sorvig@qt.io>