

# test if the PooldDataArray is constructed the way I think it is
# f.pool
ft = dtmtable.features[2]
ft.pool
unique(ft)

for j = 1:size(dtmtable.features, 2)
    ft = dtmtable.features[j]
    for i = 1:length(ft.pool)
        @assert all(ft[ft.refs .== UInt8(i)] .== ft.pool[i])
    end
end