assert_equal "@and #{@dtcs['on_or_after']}#{@dts['oai_datestamp']}\"2008-01-01 00:00:00\" #{@dtcs['on_or_before']}#{@dts['oai_datestamp']}\"2008-12-31 23:59:59\"", @pqf_query.oai_datestamp_between({ :beginning => '2008-01-01 00:00:00', :ending => '2008-12-31 23:59:59', :only_return_as_string => true })