unit tests for already resolved #1406 (#3327)
unit tests for already resolved #1406 (#3327)


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