By making sure it invokes other python executables using the same python interpreter. Also on the tests that write to an XML file, close the file handle that mkstemp() generates, otherwise Windows refuse to open and write to the filename. Side change: + For some tests, include all the environment instead of selecting specific env vars, in order to reduce verbosity. Pick-to: 6.11 6.10 6.8 Change-Id: If4ba68b5f9bf64824c888b99e9525d4bdcf42037 Reviewed-by: Mårten Nordheim <marten.nordheim@qt.io> Reviewed-by: Edward Welbourne <edward.welbourne@qt.io>