anchor.diff:      [1,2,3] = toList(delay(fun () -> ofList([1,2,3]) end)),
       ok.
   
  +average_test() ->
  +    2.0 = average([1.0,2.0,3.0]),
  +    2.0 = averageBy(fun float/1, [1,2,3]),
  +    ok.
  +
  +fold_test() ->
  +    S = seq([1,2,3]),
  +    6 = fold(fun (State, T) -> State + T end, 0, S),
  +    99 = fold(fun (State, T) -> State + T end, 99, []).
  +
  +choose_test() ->
  +    S = seq([1,2,3]),
  +    [2,3] = toList(choose(fun(1) -> undefined;
  +                             (N) -> N
  +                          end, S)).
  +
  +concat_test() ->
  +    Sources = seq([seq([1,2,3]), [4,5,6]]),
  +    [1,2,3,4,5,6] = toList(concat(Sources)).
  +
  +contains_test() ->
  +    Seq = seq([1,2,3]),
  +    true = contains(2, Seq),
  +    false = contains(5, Seq),
  +    ok.
  +
  +find_test() ->
  +    Seq = seq([1,2,3]),
  +    2 = find(fun (I) -> I > 1 end, Seq),
  +    2 = findIndex(fun (I) -> I == 3 end, Seq),
  +    true = exists(fun (I) -> I == 3 end, Seq),
  +    false = exists(fun (I) -> I == 4 end, Seq),
  +    ok.
  +
  +head_test() ->
  +    1 = head([1,2,3]),
  +    ok.
  +
  +isEmpty_test() ->
  +    false = isEmpty([1,2,3]),
  +    true = isEmpty(seq([])),
  +    ok.
  +
  +iter_test() ->
  +    Seq = seq([1,2,3]),
  +    iter(fun(I) -> put(iter_test, I) end, Seq),
  +    3 = get(iter_test).
  +
  +init_test() ->
  +    [0,1,2] = toList(init(3, fun(I) -> I end)),
  +    ok.
  +
   lists_are_seqs_test() ->
       [1,2,3] = toList([1,2,3]),
       [1,2,3] = toList(delay(fun () -> [1,2,3] end)),
  
positive.code:             end
      end.
  
  
  -ifdef(TEST).
  -include_lib("eunit/include/eunit.hrl").
  
negative.code: -module('Microsoft.FSharp.Collections.SeqModule').
  -export([
           append/2,
           average/1,
           averageBy/2,
           %cache/1,
           %cast/1,
           choose/2,
           collect/2,
           %compareWith/3
           concat/1,
           contains/2,
           % countBy/2
           delay/1,
           %distinct/1,
           %distinctBy/2,
           empty/0,
           %exactlyOne/1,
           exists/2,
           %exists2/3,
           filter/2,
           find/2,
           findIndex/2,
           fold/3,
           %forall/2
           %forall2/3
           %groupBy/2,
           head/1,
           %init/2,
           %initInfinite/1,
           isEmpty/1,
           iter/2,
           %iter2/3,
           %iteri2,
           %last/1,
  