[test] Fix the query-log-file test Testing this functionality in a CubicWebTC is awkward because the wrapping happens in handle_request, which tests basically bypass (they call core_handle directly, and do their own magic for linking the request with a cnx). The test method worked when ran on its own, but not together with the rest of the test class. So use a CubicWebServerTC instead, which goes through the whole stack.

Latest changes 
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* table of `all latest changes`_

Links below is providing useful RQL query example.

.. _all latest changes: view?rql=Any+M%2CX+WHERE+X+modification_date+M+ORDERBY+M+DESC+LIMIT+30