unit tests for fixed #1913 (#5004)
unit tests for fixed #1913 (#5004)


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