neovim/test/unit/eval/typval_spec.lua

local helpers = require('test.unit.helpers')(after_each)
local eval_helpers = require('test.unit.eval.helpers')

local itp = helpers.gen_itp(it)

local OK = helpers.OK
local eq = helpers.eq
local neq = helpers.neq
local ffi = helpers.ffi
local cimport = helpers.cimport
local to_cstr = helpers.to_cstr
local alloc_log_new = helpers.alloc_log_new

local a = eval_helpers.alloc_logging_helpers
local int = eval_helpers.int
local list = eval_helpers.list
local lst2tbl = eval_helpers.lst2tbl
local typvalt = eval_helpers.typvalt
local type_key  = eval_helpers.type_key
local li_alloc  = eval_helpers.li_alloc
local int_type  = eval_helpers.int_type
local first_di  = eval_helpers.first_di
local null_list  = eval_helpers.null_list
local null_dict  = eval_helpers.null_dict
local empty_list  = eval_helpers.empty_list
local lua2typvalt  = eval_helpers.lua2typvalt
local typvalt2lua  = eval_helpers.typvalt2lua
local null_string  = eval_helpers.null_string

local lib = cimport('./src/nvim/eval/typval.h', './src/nvim/memory.h',
                    './src/nvim/mbyte.h', './src/nvim/garray.h')

local function list_items(l)
  local lis = {}
  local li = l.lv_first
  for i = 1, l.lv_len do
    lis[i] = ffi.gc(li, nil)
    li = li.li_next
  end
  return lis
end

local function list_watch_alloc(li)
  return ffi.cast('listwatch_T*', ffi.new('listwatch_T[1]', {{lw_item=li}}))
end

local function list_watch(l, li)
  local lw = list_watch_alloc(li or l.lv_first)
  lib.tv_list_watch_add(l, lw)
  return lw
end

local function get_alloc_rets(exp_log, res)
  for i = 1,#exp_log do
    if ({malloc=true, calloc=true})[exp_log[i].func] then
      res[#res + 1] = exp_log[i].ret
    end
  end
  res.freed = function(r, n) return {func='free', args={r[n]}} end
  return exp_log
end

local to_cstr_nofree = function(v) return lib.xstrdup(v) end

local alloc_log = alloc_log_new()

before_each(function()
  alloc_log:before_each()
end)

local function clear_tmp_allocs()
  local toremove = {}
  local allocs = {}
  for i, v in ipairs(alloc_log.log) do
    if v.func == 'malloc' or v.func == 'calloc' then
      allocs[tostring(v.ret)] = i
    elseif v.func == 'realloc' or v.func == 'free' then
      if allocs[tostring(v.args[1])] then
        toremove[#toremove + 1] = allocs[tostring(v.args[1])]
        if v.func == 'free' then
          toremove[#toremove + 1] = i
        end
      end
      if v.func == 'realloc' then
        allocs[tostring(v.ret)] = i
      end
    end
  end
  table.sort(toremove)
  for i = #toremove,1,-1 do
    table.remove(alloc_log.log, toremove[i])
  end
end

after_each(function()
  alloc_log:after_each()
end)

local function ga_alloc(itemsize, growsize)
  local ga = ffi.gc(ffi.cast('garray_T*', ffi.new('garray_T[1]', {})),
                    lib.ga_clear)
  lib.ga_init(ga, itemsize or 1, growsize or 80)
  return ga
end

describe('typval.c', function()
  describe('list', function()
    describe('item', function()
      describe('alloc()/free()', function()
        itp('works', function()
          local li = li_alloc(true)
          neq(nil, li)
          lib.tv_list_item_free(li)
          alloc_log:check({
            a.li(li),
            a.freed(li),
          })
        end)
        itp('also frees the value', function()
          local li
          local s
          local l
          local tv
          li = li_alloc(true)
          li.li_tv.v_type = lib.VAR_NUMBER
          li.li_tv.vval.v_number = 10
          lib.tv_list_item_free(li)
          alloc_log:check({
            a.li(li),
            a.freed(li),
          })

          li = li_alloc(true)
          li.li_tv.v_type = lib.VAR_FLOAT
          li.li_tv.vval.v_float = 10.5
          lib.tv_list_item_free(li)
          alloc_log:check({
            a.li(li),
            a.freed(li),
          })

          li = li_alloc(true)
          li.li_tv.v_type = lib.VAR_STRING
          li.li_tv.vval.v_string = nil
          lib.tv_list_item_free(li)
          alloc_log:check({
            a.li(li),
            a.freed(alloc_log.null),
            a.freed(li),
          })

          li = li_alloc(true)
          li.li_tv.v_type = lib.VAR_STRING
          s = to_cstr_nofree('test')
          li.li_tv.vval.v_string = s
          lib.tv_list_item_free(li)
          alloc_log:check({
            a.li(li),
            a.str(s, #('test')),
            a.freed(s),
            a.freed(li),
          })

          li = li_alloc(true)
          li.li_tv.v_type = lib.VAR_LIST
          l = ffi.gc(list(), nil)
          l.lv_refcount = 2
          li.li_tv.vval.v_list = l
          lib.tv_list_item_free(li)
          alloc_log:check({
            a.li(li),
            a.list(l),
            a.freed(li),
          })
          eq(1, l.lv_refcount)

          li = li_alloc(true)
          tv = lua2typvalt({})
          tv.vval.v_dict.dv_refcount = 2
          li.li_tv = tv
          lib.tv_list_item_free(li)
          alloc_log:check({
            a.li(li),
            a.dict(tv.vval.v_dict),
            a.freed(li),
          })
          eq(1, tv.vval.v_dict.dv_refcount)
        end)
      end)
      describe('remove()', function()
        itp('works', function()
          local l = list(1, 2, 3, 4, 5, 6, 7)
          neq(nil, l)
          local lis = list_items(l)
          alloc_log:check({
            a.list(l),
            a.li(lis[1]),
            a.li(lis[2]),
            a.li(lis[3]),
            a.li(lis[4]),
            a.li(lis[5]),
            a.li(lis[6]),
            a.li(lis[7]),
          })

          lib.tv_list_item_remove(l, lis[1])
          alloc_log:check({
            a.freed(table.remove(lis, 1)),
          })
          eq(lis, list_items(l))

          lib.tv_list_item_remove(l, lis[6])
          alloc_log:check({
            a.freed(table.remove(lis)),
          })
          eq(lis, list_items(l))

          lib.tv_list_item_remove(l, lis[3])
          alloc_log:check({
            a.freed(table.remove(lis, 3)),
          })
          eq(lis, list_items(l))
        end)
        itp('works and adjusts watchers correctly', function()
          local l = ffi.gc(list(1, 2, 3, 4, 5, 6, 7), nil)
          neq(nil, l)
          local lis = list_items(l)
          -- Three watchers: pointing to first, middle and last elements.
          local lws = {
            list_watch(l, lis[1]),
            list_watch(l, lis[4]),
            list_watch(l, lis[7]),
          }

          lib.tv_list_item_remove(l, lis[4])
          ffi.gc(lis[4], lib.tv_list_item_free)
          eq({lis[1], lis[5], lis[7]}, {lws[1].lw_item, lws[2].lw_item, lws[3].lw_item})

          lib.tv_list_item_remove(l, lis[2])
          ffi.gc(lis[2], lib.tv_list_item_free)
          eq({lis[1], lis[5], lis[7]}, {lws[1].lw_item, lws[2].lw_item, lws[3].lw_item})

          lib.tv_list_item_remove(l, lis[7])
          ffi.gc(lis[7], lib.tv_list_item_free)
          eq({lis[1], lis[5], nil}, {lws[1].lw_item, lws[2].lw_item, lws[3].lw_item == nil and nil})

          lib.tv_list_item_remove(l, lis[1])
          ffi.gc(lis[1], lib.tv_list_item_free)
          eq({lis[3], lis[5], nil}, {lws[1].lw_item, lws[2].lw_item, lws[3].lw_item == nil and nil})

          alloc_log:clear()
          lib.tv_list_free(l)
          alloc_log:check({
            a.freed(lis[3]),
            a.freed(lis[5]),
            a.freed(lis[6]),
            a.freed(l),
          })
        end)
      end)
    end)
    describe('watch', function()
      describe('remove()', function()
        itp('works', function()
          local l = ffi.gc(list(1, 2, 3, 4, 5, 6, 7), nil)
          eq(nil, l.lv_watch)
          local lw = list_watch(l)
          neq(nil, l.lv_watch)
          alloc_log:clear()
          lib.tv_list_watch_remove(l, lw)
          eq(nil, l.lv_watch)
          alloc_log:check({
            -- Does not free anything.
          })
          local lws = { list_watch(l), list_watch(l), list_watch(l) }
          alloc_log:clear()
          lib.tv_list_watch_remove(l, lws[2])
          eq(lws[3], l.lv_watch)
          eq(lws[1], l.lv_watch.lw_next)
          lib.tv_list_watch_remove(l, lws[1])
          eq(lws[3], l.lv_watch)
          eq(nil, l.lv_watch.lw_next)
          lib.tv_list_watch_remove(l, lws[3])
          eq(nil, l.lv_watch)
          alloc_log:check({
            -- Does not free anything.
          })
        end)
        itp('ignores not found watchers', function()
          local l = list(1, 2, 3, 4, 5, 6, 7)
          local lw = list_watch_alloc()
          lib.tv_list_watch_remove(l, lw)
        end)
      end)
    end)
    -- add() and fix() were tested when testing tv_list_item_remove()
    describe('alloc()/free()', function()
      itp('recursively frees list with', function()
        local l1 = ffi.gc(list(1, 'abc'), nil)
        local l2 = ffi.gc(list({}), nil)
        local l3 = ffi.gc(list(empty_list), nil)
        local alloc_rets = {}
        alloc_log:check(get_alloc_rets({
          a.list(l1),
          a.li(l1.lv_first),
          a.str(l1.lv_last.li_tv.vval.v_string, #('abc')),
          a.li(l1.lv_last),
          a.list(l2),
          a.dict(l2.lv_first.li_tv.vval.v_dict),
          a.li(l2.lv_first),
          a.list(l3),
          a.list(l3.lv_first.li_tv.vval.v_list),
          a.li(l3.lv_first),
        }, alloc_rets))
        lib.tv_list_free(l1)
        alloc_log:check({
          alloc_rets:freed(2),
          alloc_rets:freed(3),
          alloc_rets:freed(4),
          alloc_rets:freed(1),
        })
        lib.tv_list_free(l2)
        alloc_log:check({
          alloc_rets:freed(6),
          alloc_rets:freed(7),
          alloc_rets:freed(5),
        })
        lib.tv_list_free(l3)
        alloc_log:check({
          alloc_rets:freed(9),
          alloc_rets:freed(10),
          alloc_rets:freed(8),
        })
      end)
      itp('does not free container items with recurse=false', function()
        local l1 = ffi.gc(list('abc', {}, empty_list), nil)
        local alloc_rets = {}
        alloc_log:check(get_alloc_rets({
          a.list(l1),
          a.str(l1.lv_first.li_tv.vval.v_string, #('abc')),
          a.li(l1.lv_first),
          a.dict(l1.lv_first.li_next.li_tv.vval.v_dict),
          a.li(l1.lv_first.li_next),
          a.list(l1.lv_last.li_tv.vval.v_list),
          a.li(l1.lv_last),
        }, alloc_rets))
        lib.tv_list_free(l1)
        alloc_log:check({
          alloc_rets:freed(2),
          alloc_rets:freed(3),
          alloc_rets:freed(4),
          alloc_rets:freed(5),
          alloc_rets:freed(6),
          alloc_rets:freed(7),
          alloc_rets:freed(1),
        })
      end)
    end)
    describe('unref()', function()
      itp('recursively frees list when reference count goes to 0', function()
        local l = ffi.gc(list(empty_list), nil)
        local alloc_rets = {}
        alloc_log:check(get_alloc_rets({
          a.list(l),
          a.list(l.lv_first.li_tv.vval.v_list),
          a.li(l.lv_first),
        }, alloc_rets))
        l.lv_refcount = 2
        lib.tv_list_unref(l)
        alloc_log:check({})
        lib.tv_list_unref(l)
        alloc_log:check({
          alloc_rets:freed(2),
          alloc_rets:freed(3),
          alloc_rets:freed(1),
        })
      end)
    end)
    describe('remove_items()', function()
      itp('works', function()
        local l_tv = lua2typvalt({1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13})
        local l = l_tv.vval.v_list
        local lis = list_items(l)
        -- Three watchers: pointing to first, middle and last elements.
        local lws = {
          list_watch(l, lis[1]),
          list_watch(l, lis[7]),
          list_watch(l, lis[13]),
        }
        alloc_log:clear()

        lib.tv_list_remove_items(l, lis[1], lis[3])
        eq({4, 5, 6, 7, 8, 9, 10, 11, 12, 13}, typvalt2lua(l_tv))
        eq({lis[4], lis[7], lis[13]}, {lws[1].lw_item, lws[2].lw_item, lws[3].lw_item})

        lib.tv_list_remove_items(l, lis[11], lis[13])
        eq({4, 5, 6, 7, 8, 9, 10}, typvalt2lua(l_tv))
        eq({lis[4], lis[7], nil}, {lws[1].lw_item, lws[2].lw_item, lws[3].lw_item == nil and nil})

        lib.tv_list_remove_items(l, lis[6], lis[8])
        eq({4, 5, 9, 10}, typvalt2lua(l_tv))
        eq({lis[4], lis[9], nil}, {lws[1].lw_item, lws[2].lw_item, lws[3].lw_item == nil and nil})

        lib.tv_list_remove_items(l, lis[4], lis[10])
        eq(empty_list, typvalt2lua(l_tv))
        eq({true, true, true}, {lws[1].lw_item == nil, lws[2].lw_item == nil, lws[3].lw_item == nil})

        alloc_log:check({})
      end)
    end)
    describe('insert', function()
      describe('()', function()
        itp('works', function()
          local l_tv = lua2typvalt({1, 2, 3, 4, 5, 6, 7})
          local l = l_tv.vval.v_list
          local lis = list_items(l)
          local li

          li = li_alloc(true)
          li.li_tv = {v_type=lib.VAR_FLOAT, vval={v_float=100500}}
          lib.tv_list_insert(l, li, nil)
          eq(l.lv_last, li)
          eq({1, 2, 3, 4, 5, 6, 7, 100500}, typvalt2lua(l_tv))

          li = li_alloc(true)
          li.li_tv = {v_type=lib.VAR_FLOAT, vval={v_float=0}}
          lib.tv_list_insert(l, li, lis[1])
          eq(l.lv_first, li)
          eq({0, 1, 2, 3, 4, 5, 6, 7, 100500}, typvalt2lua(l_tv))

          li = li_alloc(true)
          li.li_tv = {v_type=lib.VAR_FLOAT, vval={v_float=4.5}}
          lib.tv_list_insert(l, li, lis[5])
          eq(list_items(l)[6], li)
          eq({0, 1, 2, 3, 4, 4.5, 5, 6, 7, 100500}, typvalt2lua(l_tv))
        end)
        itp('works with an empty list', function()
          local l_tv = lua2typvalt(empty_list)
          local l = l_tv.vval.v_list

          eq(nil, l.lv_first)
          eq(nil, l.lv_last)

          local li = li_alloc(true)
          li.li_tv = {v_type=lib.VAR_FLOAT, vval={v_float=100500}}
          lib.tv_list_insert(l, li, nil)
          eq(l.lv_last, li)
          eq({100500}, typvalt2lua(l_tv))
        end)
      end)
      describe('tv()', function()
        itp('works', function()
          local l_tv = lua2typvalt(empty_list)
          local l = l_tv.vval.v_list

          local l_l_tv = lua2typvalt(empty_list)
          alloc_log:clear()
          local l_l = l_l_tv.vval.v_list
          eq(1, l_l.lv_refcount)
          lib.tv_list_insert_tv(l, l_l_tv, nil)
          eq(2, l_l.lv_refcount)
          eq(l_l, l.lv_first.li_tv.vval.v_list)
          alloc_log:check({
            a.li(l.lv_first),
          })

          local l_s_tv = lua2typvalt('test')
          alloc_log:check({
            a.str(l_s_tv.vval.v_string, 'test'),
          })
          lib.tv_list_insert_tv(l, l_s_tv, l.lv_first)
          alloc_log:check({
            a.li(l.lv_first),
            a.str(l.lv_first.li_tv.vval.v_string, 'test'),
          })

          eq({'test', empty_list}, typvalt2lua(l_tv))
        end)
      end)
    end)
    describe('append', function()
      describe('list()', function()
        itp('works', function()
          local l_tv = lua2typvalt(empty_list)
          local l = l_tv.vval.v_list

          local l_l = list(1)
          alloc_log:clear()
          eq(1, l_l.lv_refcount)
          lib.tv_list_append_list(l, l_l)
          eq(2, l_l.lv_refcount)
          eq(l_l, l.lv_first.li_tv.vval.v_list)
          alloc_log:check({
            a.li(l.lv_last),
          })

          lib.tv_list_append_list(l, nil)
          alloc_log:check({
            a.li(l.lv_last),
          })

          eq({{1}, null_list}, typvalt2lua(l_tv))
        end)
      end)
      describe('dict()', function()
        itp('works', function()
          local l_tv = lua2typvalt(empty_list)
          local l = l_tv.vval.v_list

          local l_d_tv = lua2typvalt({test=1})
          local l_d = l_d_tv.vval.v_dict
          alloc_log:clear()
          eq(1, l_d.dv_refcount)
          lib.tv_list_append_dict(l, l_d)
          eq(2, l_d.dv_refcount)
          eq(l_d, l.lv_first.li_tv.vval.v_list)
          alloc_log:check({
            a.li(l.lv_last),
          })

          lib.tv_list_append_dict(l, nil)
          alloc_log:check({
            a.li(l.lv_last),
          })

          eq({{test=1}, null_dict}, typvalt2lua(l_tv))
        end)
      end)
      describe('string()', function()
        itp('works', function()
          local l_tv = lua2typvalt(empty_list)
          local l = l_tv.vval.v_list

          alloc_log:clear()
          lib.tv_list_append_string(l, 'test', 3)
          alloc_log:check({
            a.str(l.lv_last.li_tv.vval.v_string, 'tes'),
            a.li(l.lv_last),
          })

          lib.tv_list_append_string(l, nil, 0)
          alloc_log:check({
            a.li(l.lv_last),
          })

          lib.tv_list_append_string(l, nil, -1)
          alloc_log:check({
            a.li(l.lv_last),
          })

          lib.tv_list_append_string(l, 'test', -1)
          alloc_log:check({
            a.str(l.lv_last.li_tv.vval.v_string, 'test'),
            a.li(l.lv_last),
          })

          eq({'tes', null_string, null_string, 'test'}, typvalt2lua(l_tv))
        end)
      end)
      describe('allocated string()', function()
        itp('works', function()
          local l_tv = lua2typvalt(empty_list)
          local l = l_tv.vval.v_list

          local s = lib.xstrdup('test')
          alloc_log:clear()
          lib.tv_list_append_allocated_string(l, s)
          alloc_log:check({
            a.li(l.lv_last),
          })

          lib.tv_list_append_allocated_string(l, nil)
          alloc_log:check({
            a.li(l.lv_last),
          })

          lib.tv_list_append_allocated_string(l, nil)
          alloc_log:check({
            a.li(l.lv_last),
          })

          eq({'test', null_string, null_string}, typvalt2lua(l_tv))
        end)
      end)
      describe('number()', function()
        itp('works', function()
          local l_tv = lua2typvalt(empty_list)
          local l = l_tv.vval.v_list

          alloc_log:clear()
          lib.tv_list_append_number(l, -100500)
          alloc_log:check({
            a.li(l.lv_last),
          })

          lib.tv_list_append_number(l, 100500)
          alloc_log:check({
            a.li(l.lv_last),
          })

          eq({{[type_key]=int_type, value=-100500},
              {[type_key]=int_type, value=100500}}, typvalt2lua(l_tv))
        end)
      end)
    end)
    describe('copy()', function()
      local function tv_list_copy(...)
        return ffi.gc(lib.tv_list_copy(...), lib.tv_list_unref)
      end
      itp('copies NULL correctly', function()
        eq(nil, lib.tv_list_copy(nil, nil, true, 0))
        eq(nil, lib.tv_list_copy(nil, nil, false, 0))
        eq(nil, lib.tv_list_copy(nil, nil, true, 1))
        eq(nil, lib.tv_list_copy(nil, nil, false, 1))
      end)
      itp('copies list correctly without converting items', function()
        do
          local v = {{['«']='»'}, {'„'}, 1, '“', null_string, null_list, null_dict}
          local l_tv = lua2typvalt(v)
          local l = l_tv.vval.v_list
          local lis = list_items(l)
          alloc_log:clear()

          eq(1, lis[1].li_tv.vval.v_dict.dv_refcount)
          eq(1, lis[2].li_tv.vval.v_list.lv_refcount)
          local l_copy1 = tv_list_copy(nil, l, false, 0)
          eq(2, lis[1].li_tv.vval.v_dict.dv_refcount)
          eq(2, lis[2].li_tv.vval.v_list.lv_refcount)
          local lis_copy1 = list_items(l_copy1)
          eq(lis[1].li_tv.vval.v_dict, lis_copy1[1].li_tv.vval.v_dict)
          eq(lis[2].li_tv.vval.v_list, lis_copy1[2].li_tv.vval.v_list)
          eq(v, lst2tbl(l_copy1))
          alloc_log:check({
            a.list(l_copy1),
            a.li(lis_copy1[1]),
            a.li(lis_copy1[2]),
            a.li(lis_copy1[3]),
            a.li(lis_copy1[4]),
            a.str(lis_copy1[4].li_tv.vval.v_string, #v[4]),
            a.li(lis_copy1[5]),
            a.li(lis_copy1[6]),
            a.li(lis_copy1[7]),
          })
          lib.tv_list_free(ffi.gc(l_copy1, nil))
          alloc_log:clear()

          eq(1, lis[1].li_tv.vval.v_dict.dv_refcount)
          eq(1, lis[2].li_tv.vval.v_list.lv_refcount)
          local l_deepcopy1 = tv_list_copy(nil, l, true, 0)
          neq(nil, l_deepcopy1)
          eq(1, lis[1].li_tv.vval.v_dict.dv_refcount)
          eq(1, lis[2].li_tv.vval.v_list.lv_refcount)
          local lis_deepcopy1 = list_items(l_deepcopy1)
          neq(lis[1].li_tv.vval.v_dict, lis_deepcopy1[1].li_tv.vval.v_dict)
          neq(lis[2].li_tv.vval.v_list, lis_deepcopy1[2].li_tv.vval.v_list)
          eq(v, lst2tbl(l_deepcopy1))
          local di_deepcopy1 = first_di(lis_deepcopy1[1].li_tv.vval.v_dict)
          alloc_log:check({
            a.list(l_deepcopy1),
            a.li(lis_deepcopy1[1]),
            a.dict(lis_deepcopy1[1].li_tv.vval.v_dict),
            a.di(di_deepcopy1, #('«')),
            a.str(di_deepcopy1.di_tv.vval.v_string, #v[1]['«']),
            a.li(lis_deepcopy1[2]),
            a.list(lis_deepcopy1[2].li_tv.vval.v_list),
            a.li(lis_deepcopy1[2].li_tv.vval.v_list.lv_first),
            a.str(lis_deepcopy1[2].li_tv.vval.v_list.lv_first.li_tv.vval.v_string, #v[2][1]),
            a.li(lis_deepcopy1[3]),
            a.li(lis_deepcopy1[4]),
            a.str(lis_deepcopy1[4].li_tv.vval.v_string, #v[4]),
            a.li(lis_deepcopy1[5]),
            a.li(lis_deepcopy1[6]),
            a.li(lis_deepcopy1[7]),
          })
        end
        collectgarbage()
      end)
      itp('copies list correctly and converts items', function()
        local vc = ffi.gc(ffi.new('vimconv_T[1]'), function(vc)
          lib.convert_setup(vc, nil, nil)
        end)
        -- UTF-8 ↔ latin1 conversions need no iconv
        eq(OK, lib.convert_setup(vc, to_cstr('utf-8'), to_cstr('latin1')))

        local v = {{['«']='»'}, {'„'}, 1, '“', null_string, null_list, null_dict}
        local l_tv = lua2typvalt(v)
        local l = l_tv.vval.v_list
        local lis = list_items(l)
        alloc_log:clear()

        eq(1, lis[1].li_tv.vval.v_dict.dv_refcount)
        eq(1, lis[2].li_tv.vval.v_list.lv_refcount)
        local l_deepcopy1 = tv_list_copy(vc, l, true, 0)
        neq(nil, l_deepcopy1)
        eq(1, lis[1].li_tv.vval.v_dict.dv_refcount)
        eq(1, lis[2].li_tv.vval.v_list.lv_refcount)
        local lis_deepcopy1 = list_items(l_deepcopy1)
        neq(lis[1].li_tv.vval.v_dict, lis_deepcopy1[1].li_tv.vval.v_dict)
        neq(lis[2].li_tv.vval.v_list, lis_deepcopy1[2].li_tv.vval.v_list)
        eq({{['\171']='\187'}, {'\191'}, 1, '\191', null_string, null_list, null_dict},
           lst2tbl(l_deepcopy1))
        local di_deepcopy1 = first_di(lis_deepcopy1[1].li_tv.vval.v_dict)
        clear_tmp_allocs()
        alloc_log:check({
          a.list(l_deepcopy1),
          a.li(lis_deepcopy1[1]),
          a.dict(lis_deepcopy1[1].li_tv.vval.v_dict),
          a.di(di_deepcopy1, 1),
          a.str(di_deepcopy1.di_tv.vval.v_string, 2),
          a.li(lis_deepcopy1[2]),
          a.list(lis_deepcopy1[2].li_tv.vval.v_list),
          a.li(lis_deepcopy1[2].li_tv.vval.v_list.lv_first),
          a.str(lis_deepcopy1[2].li_tv.vval.v_list.lv_first.li_tv.vval.v_string, #v[2][1]),
          a.li(lis_deepcopy1[3]),
          a.li(lis_deepcopy1[4]),
          a.str(lis_deepcopy1[4].li_tv.vval.v_string, #v[4]),
          a.li(lis_deepcopy1[5]),
          a.li(lis_deepcopy1[6]),
          a.li(lis_deepcopy1[7]),
        })
      end)
      itp('returns different/same containers with(out) copyID', function()
        local l_inner_tv = lua2typvalt(empty_list)
        local l_tv = lua2typvalt({l_inner_tv, l_inner_tv})
        eq(3, l_inner_tv.vval.v_list.lv_refcount)
        local l = l_tv.vval.v_list
        eq(l.lv_first.li_tv.vval.v_list, l.lv_last.li_tv.vval.v_list)

        local l_copy1 = tv_list_copy(nil, l, true, 0)
        neq(l_copy1.lv_first.li_tv.vval.v_list, l_copy1.lv_last.li_tv.vval.v_list)
        eq({empty_list, empty_list}, lst2tbl(l_copy1))

        local l_copy2 = tv_list_copy(nil, l, true, 2)
        eq(l_copy2.lv_first.li_tv.vval.v_list, l_copy2.lv_last.li_tv.vval.v_list)
        eq({empty_list, empty_list}, lst2tbl(l_copy2))

        eq(3, l_inner_tv.vval.v_list.lv_refcount)
      end)
      itp('works with self-referencing list with copyID', function()
        local l_tv = lua2typvalt(empty_list)
        local l = l_tv.vval.v_list
        eq(1, l.lv_refcount)
        lib.tv_list_append_list(l, l)
        eq(2, l.lv_refcount)

        local l_copy1 = tv_list_copy(nil, l, true, 2)
        eq(2, l_copy1.lv_refcount)
        local v = {}
        v[1] = v
        eq(v, lst2tbl(l_copy1))

        local lis = list_items(l)
        lib.tv_list_item_remove(l, lis[1])
        eq(1, l.lv_refcount)

        local lis_copy1 = list_items(l_copy1)
        lib.tv_list_item_remove(l_copy1, lis_copy1[1])
        eq(1, l_copy1.lv_refcount)
      end)
    end)
    describe('extend()', function()
      itp('can extend list with itself', function()
        local l

        l = list(1, {})
        alloc_log:clear()
        eq(1, l.lv_refcount)
        eq(1, l.lv_last.li_tv.vval.v_dict.dv_refcount)

        lib.tv_list_extend(l, l, nil)
        alloc_log:check({
          a.li(l.lv_last.li_prev),
          a.li(l.lv_last),
        })
        eq(1, l.lv_refcount)
        eq(2, l.lv_last.li_tv.vval.v_dict.dv_refcount)
        eq({1, {}, 1, {}}, lst2tbl(l))

        l = list(1, {})
        alloc_log:clear()
        eq(1, l.lv_refcount)
        eq(1, l.lv_last.li_tv.vval.v_dict.dv_refcount)

        lib.tv_list_extend(l, l, l.lv_last)
        alloc_log:check({
          a.li(l.lv_last.li_prev.li_prev),
          a.li(l.lv_last.li_prev),
        })
        eq({1, 1, {}, {}}, lst2tbl(l))
        eq(1, l.lv_refcount)
        eq(2, l.lv_last.li_tv.vval.v_dict.dv_refcount)

        l = list(1, {})
        alloc_log:clear()
        eq(1, l.lv_refcount)
        eq(1, l.lv_last.li_tv.vval.v_dict.dv_refcount)

        lib.tv_list_extend(l, l, l.lv_first)
        alloc_log:check({
          a.li(l.lv_first),
          a.li(l.lv_first.li_next),
        })
        eq({1, {}, 1, {}}, lst2tbl(l))
        eq(1, l.lv_refcount)
        eq(2, l.lv_last.li_tv.vval.v_dict.dv_refcount)
      end)
      itp('can extend list with an empty list', function()
        local l = list(1, {})
        local el = list()
        alloc_log:clear()
        eq(1, l.lv_refcount)
        eq(1, l.lv_last.li_tv.vval.v_dict.dv_refcount)
        eq(1, el.lv_refcount)

        lib.tv_list_extend(l, el, nil)
        alloc_log:check({
        })
        eq(1, l.lv_refcount)
        eq(1, l.lv_last.li_tv.vval.v_dict.dv_refcount)
        eq(1, el.lv_refcount)
        eq({1, {}}, lst2tbl(l))

        lib.tv_list_extend(l, el, l.lv_first)
        alloc_log:check({
        })
        eq(1, l.lv_refcount)
        eq(1, l.lv_last.li_tv.vval.v_dict.dv_refcount)
        eq(1, el.lv_refcount)
        eq({1, {}}, lst2tbl(l))

        lib.tv_list_extend(l, el, l.lv_last)
        alloc_log:check({
        })
        eq(1, l.lv_refcount)
        eq(1, l.lv_last.li_tv.vval.v_dict.dv_refcount)
        eq(1, el.lv_refcount)
        eq({1, {}}, lst2tbl(l))
      end)
      itp('can extend list with another non-empty list', function()
        local l
        local l2 = list(42, empty_list)
        eq(1, l2.lv_refcount)
        eq(1, l2.lv_last.li_tv.vval.v_list.lv_refcount)

        l = ffi.gc(list(1, {}), nil)
        alloc_log:clear()
        eq(1, l.lv_refcount)
        eq(1, l.lv_last.li_tv.vval.v_dict.dv_refcount)

        lib.tv_list_extend(l, l2, nil)
        alloc_log:check({
          a.li(l.lv_last.li_prev),
          a.li(l.lv_last),
        })
        eq(1, l2.lv_refcount)
        eq(2, l2.lv_last.li_tv.vval.v_list.lv_refcount)
        eq({1, {}, 42, empty_list}, lst2tbl(l))
        lib.tv_list_free(l)
        eq(1, l2.lv_last.li_tv.vval.v_list.lv_refcount)

        l = ffi.gc(list(1, {}), nil)
        alloc_log:clear()
        eq(1, l.lv_refcount)
        eq(1, l.lv_last.li_tv.vval.v_dict.dv_refcount)

        lib.tv_list_extend(l, l2, l.lv_first)
        alloc_log:check({
          a.li(l.lv_first),
          a.li(l.lv_first.li_next),
        })
        eq(1, l2.lv_refcount)
        eq(2, l2.lv_last.li_tv.vval.v_list.lv_refcount)
        eq({42, empty_list, 1, {}}, lst2tbl(l))
        lib.tv_list_free(l)
        eq(1, l2.lv_last.li_tv.vval.v_list.lv_refcount)

        l = ffi.gc(list(1, {}), nil)
        alloc_log:clear()
        eq(1, l.lv_refcount)
        eq(1, l.lv_last.li_tv.vval.v_dict.dv_refcount)

        lib.tv_list_extend(l, l2, l.lv_last)
        alloc_log:check({
          a.li(l.lv_first.li_next),
          a.li(l.lv_first.li_next.li_next),
        })
        eq(1, l2.lv_refcount)
        eq(2, l2.lv_last.li_tv.vval.v_list.lv_refcount)
        eq({1, 42, empty_list, {}}, lst2tbl(l))
        lib.tv_list_free(l)
        eq(1, l2.lv_last.li_tv.vval.v_list.lv_refcount)
      end)
    end)
    describe('concat()', function()
      itp('works with NULL lists', function()
        local l = list(1, {})
        alloc_log:clear()
        eq(1, l.lv_refcount)
        eq(1, l.lv_last.li_tv.vval.v_dict.dv_refcount)

        local rettv1 = typvalt()
        eq(OK, lib.tv_list_concat(nil, l, rettv1))
        eq(1, l.lv_refcount)
        eq(tonumber(lib.VAR_LIST), tonumber(rettv1.v_type))
        eq({1, {}}, typvalt2lua(rettv1))
        eq(1, rettv1.vval.v_list.lv_refcount)
        alloc_log:check({
          a.list(rettv1.vval.v_list),
          a.li(rettv1.vval.v_list.lv_first),
          a.li(rettv1.vval.v_list.lv_last),
        })
        eq(2, l.lv_last.li_tv.vval.v_dict.dv_refcount)

        local rettv2 = typvalt()
        eq(OK, lib.tv_list_concat(l, nil, rettv2))
        eq(1, l.lv_refcount)
        eq(tonumber(lib.VAR_LIST), tonumber(rettv2.v_type))
        eq({1, {}}, typvalt2lua(rettv2))
        eq(1, rettv2.vval.v_list.lv_refcount)
        alloc_log:check({
          a.list(rettv2.vval.v_list),
          a.li(rettv2.vval.v_list.lv_first),
          a.li(rettv2.vval.v_list.lv_last),
        })
        eq(3, l.lv_last.li_tv.vval.v_dict.dv_refcount)

        local rettv3 = typvalt()
        eq(OK, lib.tv_list_concat(nil, nil, rettv3))
        eq(tonumber(lib.VAR_LIST), tonumber(rettv3.v_type))
        eq(null_list, typvalt2lua(rettv3))
        alloc_log:check({})
      end)
      itp('works with two different lists', function()
        local l1 = list(1, {})
        local l2 = list(3, empty_list)
        eq(1, l1.lv_refcount)
        eq(1, l1.lv_last.li_tv.vval.v_dict.dv_refcount)
        eq(1, l2.lv_refcount)
        eq(1, l2.lv_last.li_tv.vval.v_list.lv_refcount)
        alloc_log:clear()

        local rettv = typvalt()
        eq(OK, lib.tv_list_concat(l1, l2, rettv))
        eq(1, l1.lv_refcount)
        eq(2, l1.lv_last.li_tv.vval.v_dict.dv_refcount)
        eq(1, l2.lv_refcount)
        eq(2, l2.lv_last.li_tv.vval.v_list.lv_refcount)
        alloc_log:check({
          a.list(rettv.vval.v_list),
          a.li(rettv.vval.v_list.lv_first),
          a.li(rettv.vval.v_list.lv_first.li_next),
          a.li(rettv.vval.v_list.lv_last.li_prev),
          a.li(rettv.vval.v_list.lv_last),
        })
        eq({1, {}, 3, empty_list}, typvalt2lua(rettv))
      end)
      itp('can concatenate list with itself', function()
        local l = list(1, {})
        eq(1, l.lv_refcount)
        eq(1, l.lv_last.li_tv.vval.v_dict.dv_refcount)
        alloc_log:clear()

        local rettv = typvalt()
        eq(OK, lib.tv_list_concat(l, l, rettv))
        eq(1, l.lv_refcount)
        eq(3, l.lv_last.li_tv.vval.v_dict.dv_refcount)
        alloc_log:check({
          a.list(rettv.vval.v_list),
          a.li(rettv.vval.v_list.lv_first),
          a.li(rettv.vval.v_list.lv_first.li_next),
          a.li(rettv.vval.v_list.lv_last.li_prev),
          a.li(rettv.vval.v_list.lv_last),
        })
        eq({1, {}, 1, {}}, typvalt2lua(rettv))
      end)
      itp('can concatenate empty non-NULL lists', function()
        local l = list(1, {})
        local le = list()
        local le2 = list()
        eq(1, l.lv_refcount)
        eq(1, l.lv_last.li_tv.vval.v_dict.dv_refcount)
        eq(1, le.lv_refcount)
        eq(1, le2.lv_refcount)
        alloc_log:clear()

        local rettv1 = typvalt()
        eq(OK, lib.tv_list_concat(l, le, rettv1))
        eq(1, l.lv_refcount)
        eq(2, l.lv_last.li_tv.vval.v_dict.dv_refcount)
        eq(1, le.lv_refcount)
        eq(1, le2.lv_refcount)
        alloc_log:check({
          a.list(rettv1.vval.v_list),
          a.li(rettv1.vval.v_list.lv_first),
          a.li(rettv1.vval.v_list.lv_last),
        })
        eq({1, {}}, typvalt2lua(rettv1))

        local rettv2 = typvalt()
        eq(OK, lib.tv_list_concat(le, l, rettv2))
        eq(1, l.lv_refcount)
        eq(3, l.lv_last.li_tv.vval.v_dict.dv_refcount)
        eq(1, le.lv_refcount)
        eq(1, le2.lv_refcount)
        alloc_log:check({
          a.list(rettv2.vval.v_list),
          a.li(rettv2.vval.v_list.lv_first),
          a.li(rettv2.vval.v_list.lv_last),
        })
        eq({1, {}}, typvalt2lua(rettv2))

        local rettv3 = typvalt()
        eq(OK, lib.tv_list_concat(le, le, rettv3))
        eq(1, l.lv_refcount)
        eq(3, l.lv_last.li_tv.vval.v_dict.dv_refcount)
        eq(1, le.lv_refcount)
        eq(1, le2.lv_refcount)
        alloc_log:check({
          a.list(rettv3.vval.v_list),
        })
        eq(empty_list, typvalt2lua(rettv3))

        local rettv4 = typvalt()
        eq(OK, lib.tv_list_concat(le, le2, rettv4))
        eq(1, l.lv_refcount)
        eq(3, l.lv_last.li_tv.vval.v_dict.dv_refcount)
        eq(1, le.lv_refcount)
        eq(1, le2.lv_refcount)
        alloc_log:check({
          a.list(rettv4.vval.v_list),
        })
        eq(empty_list, typvalt2lua(rettv4))
      end)
    end)
    describe('join()', function()
      local function list_join(l, sep, ret)
        local ga = ga_alloc()
        eq(ret or OK, lib.tv_list_join(ga, l, sep))
        if ga.ga_data == nil then return ''
        else return ffi.string(ga.ga_data)
        end
      end
      itp('works', function()
        local l
        l = list('boo', 'far')
        eq('boo far', list_join(l, ' '))
        eq('boofar', list_join(l, ''))

        l = list('boo')
        eq('boo', list_join(l, ' '))

        l = list()
        eq('', list_join(l, ' '))

        l = list({}, 'far')
        eq('{} far', list_join(l, ' '))

        local recursive_list = {}
        recursive_list[1] = recursive_list
        l = ffi.gc(list(recursive_list, 'far'), nil)
        eq('[[...@0]] far', list_join(l, ' '))

        local recursive_l = l.lv_first.li_tv.vval.v_list
        local recursive_li = recursive_l.lv_first
        lib.tv_list_item_remove(recursive_l, recursive_li)
        lib.tv_list_free(l, true)
      end)
    end)
    describe('equal()', function()
      itp('compares empty and NULL lists correctly', function()
        local l = list()
        local l2 = list()

        -- NULL lists are not equal to empty lists
        eq(false, lib.tv_list_equal(l, nil, true, false))
        eq(false, lib.tv_list_equal(nil, l, false, false))
        eq(false, lib.tv_list_equal(nil, l, false, true))
        eq(false, lib.tv_list_equal(l, nil, true, true))

        -- Yet NULL lists are equal themselves
        eq(true, lib.tv_list_equal(nil, nil, true, false))
        eq(true, lib.tv_list_equal(nil, nil, false, false))
        eq(true, lib.tv_list_equal(nil, nil, false, true))
        eq(true, lib.tv_list_equal(nil, nil, true, true))

        -- As well as empty lists
        eq(true, lib.tv_list_equal(l, l, true, false))
        eq(true, lib.tv_list_equal(l, l2, false, false))
        eq(true, lib.tv_list_equal(l2, l, false, true))
        eq(true, lib.tv_list_equal(l2, l2, true, true))
      end)
      -- Must not use recursive=true argument in the following tests because it
      -- indicates that tv_equal_recurse_limit and recursive_cnt were set which
      -- is essential. This argument will be set when comparing inner lists.
      itp('compares lists correctly when case is not ignored', function()
        local l1 = list('abc', {1, 2, 'Abc'}, 'def')
        local l2 = list('abc', {1, 2, 'Abc'})
        local l3 = list('abc', {1, 2, 'Abc'}, 'Def')
        local l4 = list('abc', {1, 2, 'Abc', 4}, 'def')
        local l5 = list('Abc', {1, 2, 'Abc'}, 'def')
        local l6 = list('abc', {1, 2, 'Abc'}, 'def')
        local l7 = list('abc', {1, 2, 'abc'}, 'def')
        local l8 = list('abc', nil, 'def')
        local l9 = list('abc', {1, 2, nil}, 'def')

        eq(true, lib.tv_list_equal(l1, l1, false, false))
        eq(false, lib.tv_list_equal(l1, l2, false, false))
        eq(false, lib.tv_list_equal(l1, l3, false, false))
        eq(false, lib.tv_list_equal(l1, l4, false, false))
        eq(false, lib.tv_list_equal(l1, l5, false, false))
        eq(true, lib.tv_list_equal(l1, l6, false, false))
        eq(false, lib.tv_list_equal(l1, l7, false, false))
        eq(false, lib.tv_list_equal(l1, l8, false, false))
        eq(false, lib.tv_list_equal(l1, l9, false, false))
      end)
      itp('compares lists correctly when case is ignored', function()
        local l1 = list('abc', {1, 2, 'Abc'}, 'def')
        local l2 = list('abc', {1, 2, 'Abc'})
        local l3 = list('abc', {1, 2, 'Abc'}, 'Def')
        local l4 = list('abc', {1, 2, 'Abc', 4}, 'def')
        local l5 = list('Abc', {1, 2, 'Abc'}, 'def')
        local l6 = list('abc', {1, 2, 'Abc'}, 'def')
        local l7 = list('abc', {1, 2, 'abc'}, 'def')
        local l8 = list('abc', nil, 'def')
        local l9 = list('abc', {1, 2, nil}, 'def')

        eq(true, lib.tv_list_equal(l1, l1, true, false))
        eq(false, lib.tv_list_equal(l1, l2, true, false))
        eq(true, lib.tv_list_equal(l1, l3, true, false))
        eq(false, lib.tv_list_equal(l1, l4, true, false))
        eq(true, lib.tv_list_equal(l1, l5, true, false))
        eq(true, lib.tv_list_equal(l1, l6, true, false))
        eq(true, lib.tv_list_equal(l1, l7, true, false))
        eq(false, lib.tv_list_equal(l1, l8, true, false))
        eq(false, lib.tv_list_equal(l1, l9, true, false))
      end)
    end)
    describe('find', function()
      describe('()', function()
        itp('correctly indexes list', function()
          local l = list(1, 2, 3, 4, 5)
          local lis = list_items(l)
          clear_alloc_log()

          eq(nil, lib.tv_list_find(nil, -1))
          eq(nil, lib.tv_list_find(nil, 0))
          eq(nil, lib.tv_list_find(nil, 1))

          eq(nil, lib.tv_list_find(l, 5))
          eq(nil, lib.tv_list_find(l, -6))
          eq(lis[1], lib.tv_list_find(l, -5))
          eq(lis[5], lib.tv_list_find(l, 4))
          eq(lis[3], lib.tv_list_find(l, 2))
          eq(lis[3], lib.tv_list_find(l, -3))
          eq(lis[3], lib.tv_list_find(l, 2))
          eq(lis[3], lib.tv_list_find(l, 2))
          eq(lis[3], lib.tv_list_find(l, -3))

          l.lv_idx_item = nil
          eq(lis[1], lib.tv_list_find(l, -5))
          l.lv_idx_item = nil
          eq(lis[5], lib.tv_list_find(l, 4))
          l.lv_idx_item = nil
          eq(lis[3], lib.tv_list_find(l, 2))
          l.lv_idx_item = nil
          eq(lis[3], lib.tv_list_find(l, -3))
          l.lv_idx_item = nil
          eq(lis[3], lib.tv_list_find(l, 2))
          l.lv_idx_item = nil
          eq(lis[3], lib.tv_list_find(l, 2))
          l.lv_idx_item = nil
          eq(lis[3], lib.tv_list_find(l, -3))

          l.lv_idx_item = nil
          eq(lis[3], lib.tv_list_find(l, 2))
          eq(lis[1], lib.tv_list_find(l, -5))
          eq(lis[3], lib.tv_list_find(l, 2))
          eq(lis[5], lib.tv_list_find(l, 4))
          eq(lis[3], lib.tv_list_find(l, 2))
          eq(lis[3], lib.tv_list_find(l, 2))
          eq(lis[3], lib.tv_list_find(l, 2))
          eq(lis[3], lib.tv_list_find(l, -3))
          eq(lis[3], lib.tv_list_find(l, 2))
          eq(lis[3], lib.tv_list_find(l, 2))
          eq(lis[3], lib.tv_list_find(l, 2))
          eq(lis[3], lib.tv_list_find(l, -3))

          check_alloc_log({})
        end)
      end)
      local function check_emsg(f, msg)
        local saved_last_msg_hist = lib.last_msg_hist
        local ret = {f()}
        if msg ~= nil then
          neq(saved_last_msg_hist, lib.last_msg_hist)
          eq(msg, ffi.string(lib.last_msg_hist.msg))
        else
          eq(saved_last_msg_hist, lib.last_msg_hist)
        end
        return unpack(ret)
      end
      describe('nr()', function()
        local function tv_list_find_nr(l, n, msg)
          return check_emsg(function()
            local err = ffi.new('bool[1]', {false})
            local ret = lib.tv_list_find_nr(l, n, err)
            return (err[0] == true), ret
          end, msg)
        end
        it('returns correct number', function()
          local l = list(int(1), int(2), int(3), int(4), int(5))
          clear_alloc_log()

          eq({false, 1}, {tv_list_find_nr(l, -5)})
          eq({false, 5}, {tv_list_find_nr(l, 4)})
          eq({false, 3}, {tv_list_find_nr(l, 2)})
          eq({false, 3}, {tv_list_find_nr(l, -3)})

          check_alloc_log({})
        end)
        it('returns correct number when given a string', function()
          local l = list('1', '2', '3', '4', '5')
          clear_alloc_log()

          eq({false, 1}, {tv_list_find_nr(l, -5)})
          eq({false, 5}, {tv_list_find_nr(l, 4)})
          eq({false, 3}, {tv_list_find_nr(l, 2)})
          eq({false, 3}, {tv_list_find_nr(l, -3)})

          check_alloc_log({})
        end)
        it('returns zero when given a NULL string', function()
          local l = list(null_string)
          clear_alloc_log()

          eq({false, 0}, {tv_list_find_nr(l, 0)})

          check_alloc_log({})
        end)
        it('errors out on NULL lists', function()
          eq({true, -1}, {tv_list_find_nr(nil, -5)})
          eq({true, -1}, {tv_list_find_nr(nil, 4)})
          eq({true, -1}, {tv_list_find_nr(nil, 2)})
          eq({true, -1}, {tv_list_find_nr(nil, -3)})

          check_alloc_log({})
        end)
        it('errors out on out-of-range indexes', function()
          local l = list(int(1), int(2), int(3), int(4), int(5))
          clear_alloc_log()

          eq({true, -1}, {tv_list_find_nr(l, -6)})
          eq({true, -1}, {tv_list_find_nr(l, 5)})

          check_alloc_log({})
        end)
        it('errors out on invalid types', function()
          local l = list(1, empty_list, {})

          eq({true, 0}, {tv_list_find_nr(l, 0, 'E805: Using a Float as a Number')})
          eq({true, 0}, {tv_list_find_nr(l, 1, 'E745: Using a List as a Number')})
          eq({true, 0}, {tv_list_find_nr(l, 2, 'E728: Using a Dictionary as a Number')})
          eq({true, 0}, {tv_list_find_nr(l, -1, 'E728: Using a Dictionary as a Number')})
          eq({true, 0}, {tv_list_find_nr(l, -2, 'E745: Using a List as a Number')})
          eq({true, 0}, {tv_list_find_nr(l, -3, 'E805: Using a Float as a Number')})
        end)
      end)
      local function tv_list_find_str(l, n, msg)
        return check_emsg(function()
          local ret = lib.tv_list_find_str(l, n)
          local s = nil
          if ret ~= nil then
            s = ffi.string(ret)
          end
          return s
        end, msg)
      end
      describe('str()', function()
        it('returns correct string', function()
          local l = list(int(1), int(2), int(3), int(4), int(5))
          clear_alloc_log()

          eq('1', tv_list_find_str(l, -5))
          eq('5', tv_list_find_str(l, 4))
          eq('3', tv_list_find_str(l, 2))
          eq('3', tv_list_find_str(l, -3))

          check_alloc_log({})
        end)
        it('returns string when used with VAR_STRING items', function()
          local l = list('1', '2', '3', '4', '5')
          clear_alloc_log()

          eq('1', tv_list_find_str(l, -5))
          eq('5', tv_list_find_str(l, 4))
          eq('3', tv_list_find_str(l, 2))
          eq('3', tv_list_find_str(l, -3))

          check_alloc_log({})
        end)
        it('returns empty when used with NULL string', function()
          local l = list(null_string)
          clear_alloc_log()

          eq('', tv_list_find_str(l, 0))

          check_alloc_log({})
        end)
        it('fails with error message when index is out of range', function()
          local l = list(int(1), int(2), int(3), int(4), int(5))

          eq(nil, tv_list_find_str(l, -6, 'E684: list index out of range: -6'))
          eq(nil, tv_list_find_str(l, 5, 'E684: list index out of range: 5'))
        end)
        it('fails with error message on invalid types', function()
          local l = list(1, empty_list, {})

          eq('', tv_list_find_str(l, 0, 'E806: using Float as a String'))
          eq('', tv_list_find_str(l, 1, 'E730: using List as a String'))
          eq('', tv_list_find_str(l, 2, 'E731: using Dictionary as a String'))
          eq('', tv_list_find_str(l, -1, 'E731: using Dictionary as a String'))
          eq('', tv_list_find_str(l, -2, 'E730: using List as a String'))
          eq('', tv_list_find_str(l, -3, 'E806: using Float as a String'))
        end)
      end)
    end)
  end)
end)