added test for fixed issue (#4191)
added test for fixed issue (#4191)


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