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t21test_xios: This directory contains an acceptance test which makes use of the XIOS server – we do not need use this here.
t21test_xios_t255ac: The three acceptance tests in this directory make use of the additional compositon (AC) code and it is possible to run this test (a) without AC as in t21test, (b) with additional AC included, and (c) with both additional AC and using the XIOS server.
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