anchor.diff:      UpNodes = AvailNodeFun(Service, CHBin) -- [Node|DownNodes],
   
       %% We don't know what partition this subpartition is in, but we
  -    %% can request a preflist for it by subtracting RingIndexInc from
  -    %% the subpartition index to jump back a keyspace and send that
  -    %% new value to `riak_core_apl' as a document index.
  -    DocIdx = convert(SubpID, subpartition_index) - RingIndexInc,
  +    %% can request a preflist for it by converting the subpartition to
  +    %% a document index.
  +    %%
  +    %% Unlike traditional coverage filters to document key hash
  +    %% mappings which have off-by-one adjustments, subpartition masks
  +    %% map directly against the relevant key hashes.
  +    DocIdx = convert(SubpID, subpartition_index),
       PrefList =
           docidx_to_preflist(DocIdx, NVal, Offset, UpNodes, CHBin),
       singular_preflist_to_chunk(PrefList, SubpID).
  
positive.code:     chashbin:create(CHash).
  
  cpteardown(_) ->
      meck:unload().
  
  test_create_subpartition_plan(CHBin) ->
      Plan =
  
negative.code:      fun cpsetup/0,
       fun cpteardown/1,
       [fun test_create_traditional_plan/1,
        fun test_create_subpartition_plan/1,
        fun test_replace_subpartition/1]
      }.
  
  chash_init() ->
  