1 files changed, 128 insertions, 0 deletions
diff --git a/test/etap/021-btree-reductions.t b/test/etap/021-btree-reductions.t
new file mode 100644
index 00000000..df418a56
--- /dev/null
+++ b/test/etap/021-btree-reductions.t
@@ -0,0 +1,128 @@
+#!/usr/bin/env escript
+%% -*- erlang -*-
+%%! -pa ./src/couchdb -sasl errlog_type error -boot start_sasl -noshell
+
+-define(FILE_NAME, "./t/temp.021").
+-define(ROWS, 1000).
+
+main(_) ->
+    etap:plan(8),
+    case (catch test()) of
+        ok ->
+            etap:end_tests();
+        Other ->
+            etap:diag(io_lib:format("Test died abnormally: ~p", [Other])),
+            etap:bail()
+    end,
+    ok.
+
+test()->
+    ReduceFun = fun
+        (reduce, KVs) -> length(KVs);
+        (rereduce, Reds) -> lists:sum(Reds)
+    end,
+    
+    {ok, Fd} = couch_file:open(?FILE_NAME, [create,overwrite]),
+    {ok, Btree} = couch_btree:open(nil, Fd, [{reduce, ReduceFun}]),
+    
+    % Create a list, of {"even", Value} or {"odd", Value} pairs.
+    {_, EvenOddKVs} = lists:foldl(fun(Idx, {Key, Acc}) ->
+        case Key of
+            "even" -> {"odd", [{{Key, Idx}, 1} | Acc]};
+            _ -> {"even", [{{Key, Idx}, 1} | Acc]}
+        end
+    end, {"odd", []}, lists:seq(1, ?ROWS)),
+
+    {ok, Btree2} = couch_btree:add_remove(Btree, EvenOddKVs, []),
+
+    GroupFun = fun({K1, _}, {K2, _}) -> K1 == K2 end,
+    FoldFun = fun(GroupedKey, Unreduced, Acc) ->
+        {ok, [{GroupedKey, couch_btree:final_reduce(Btree2, Unreduced)} | Acc]}
+    end,
+
+    {SK1, EK1} = {{"even", -1}, {"even", foo}},
+    {SK2, EK2} = {{"odd", -1}, {"odd", foo}},
+
+    etap:fun_is(
+        fun
+            ({ok, [{{"odd", _}, ?ROWS div 2}, {{"even", _}, ?ROWS div 2}]}) ->
+                true;
+            (_) ->
+                false
+        end,    
+        couch_btree:fold_reduce(Btree2, nil, nil, GroupFun, FoldFun, []),
+        "Reduction works with no specified direction, startkey, or endkey."
+    ),
+
+    etap:fun_is(
+        fun
+            ({ok, [{{"odd", _}, ?ROWS div 2}, {{"even", _}, ?ROWS div 2}]}) ->
+                true;
+            (_) ->
+                false
+        end,
+        couch_btree:fold_reduce(Btree2, fwd, nil, nil, GroupFun, FoldFun, []),
+        "Reducing forward works with no startkey or endkey."
+    ),
+
+    etap:fun_is(
+        fun
+            ({ok, [{{"even", _}, ?ROWS div 2}, {{"odd", _}, ?ROWS div 2}]}) ->
+                true;
+            (_) ->
+                false
+        end,
+        couch_btree:fold_reduce(Btree2, rev, nil, nil, GroupFun, FoldFun, []),
+        "Reducing backwards works with no startkey or endkey."
+    ),
+    
+    etap:fun_is(
+        fun
+            ({ok, [{{"odd", _}, ?ROWS div 2}, {{"even", _}, ?ROWS div 2}]}) ->
+                true;
+            (_) ->
+                false
+        end,
+        couch_btree:fold_reduce(Btree2, fwd, SK1, EK2, GroupFun, FoldFun, []),
+        "Reducing works over the entire range with startkey and endkey set."
+    ),
+    
+    etap:fun_is(
+        fun
+            ({ok, [{{"even", _}, ?ROWS div 2}]}) -> true;
+            (_) -> false
+        end,
+        couch_btree:fold_reduce(Btree2, fwd, SK1, EK1, GroupFun, FoldFun, []),
+        "Reducing foward over first half works with a startkey and endkey."
+    ),
+
+    etap:fun_is(
+        fun
+            ({ok, [{{"odd", _}, ?ROWS div 2}]}) -> true;
+            (_) -> false
+        end,
+        couch_btree:fold_reduce(Btree2, fwd, SK2, EK2, GroupFun, FoldFun, []),
+        "Reducing foward over second half works with second startkey and endkey"
+    ),
+
+    etap:fun_is(
+        fun
+            ({ok, [{{"odd", _}, ?ROWS div 2}]}) -> true;
+            (_) -> false
+        end,
+        couch_btree:fold_reduce(Btree2, rev, EK2, SK2, GroupFun, FoldFun, []),
+        "Reducing in reverse works after swapping the startkey and endkey."
+    ),
+    
+    etap:fun_is(
+        fun
+            ({ok, [{{"even", _}, ?ROWS div 2}, {{"odd", _}, ?ROWS div 2}]}) ->
+                true;
+            (_) ->
+                false
+        end,
+        couch_btree:fold_reduce(Btree2, rev, EK2, SK1, GroupFun, FoldFun, []),
+        "Reducing in reverse results in reversed accumulator."
+    ),
+
+    couch_file:close(Fd).