add tests of dtq package integration (#2686)
add tests of dtq package integration (#2686)


jangorecki/data.table,vlulla/data.table,jangorecki/data.table,vlulla/data.table,jangorecki/data.table,Rdatatable/data.table,Rdatatable/data.table,vlulla/data.table,vlulla/data.table,Rdatatable/data.table,jangorecki/data.table,Rdatatable/data.table