-- $Id: testes/api.lua $
-- See Copyright Notice in file all.lua

if T==nil then
    (Message or print)('\n >>> testC not active: skipping API tests <<<\n')
    return
  end
  
  local debug = require "debug"
  
  local pack = table.pack
  
  
  -- standard error message for memory errors
  local MEMERRMSG = "not enough memory"
  
  function tcheck (t1, t2)
    assert(t1.n == (t2.n or #t2) + 1)
    for i = 2, t1.n do assert(t1[i] == t2[i - 1]) end
  end
  
  
  local function checkerr (msg, f, ...)
    local stat, err = pcall(f, ...)
    assert(not stat and string.find(err, msg))
  end
  
  
  print('testing C API')
  
  a = T.testC("pushvalue R; return 1")
  assert(a == debug.getregistry())
  
  
  -- absindex
  assert(T.testC("settop 10; absindex -1; return 1") == 10)
  assert(T.testC("settop 5; absindex -5; return 1") == 1)
  assert(T.testC("settop 10; absindex 1; return 1") == 1)
  assert(T.testC("settop 10; absindex R; return 1") < -10)
  
  -- testing alignment
  a = T.d2s(12458954321123.0)
  assert(a == string.pack("d", 12458954321123.0))
  assert(T.s2d(a) == 12458954321123.0)
  
  a,b,c = T.testC("pushnum 1; pushnum 2; pushnum 3; return 2")
  assert(a == 2 and b == 3 and not c)
  
  f = T.makeCfunc("pushnum 1; pushnum 2; pushnum 3; return 2")
  a,b,c = f()
  assert(a == 2 and b == 3 and not c)
  
  -- test that all trues are equal
  a,b,c = T.testC("pushbool 1; pushbool 2; pushbool 0; return 3")
  assert(a == b and a == true and c == false)
  a,b,c = T.testC"pushbool 0; pushbool 10; pushnil;\
                        tobool -3; tobool -3; tobool -3; return 3"
  assert(a==false and b==true and c==false)
  
  
  a,b,c = T.testC("gettop; return 2", 10, 20, 30, 40)
  assert(a == 40 and b == 5 and not c)
  
  t = pack(T.testC("settop 5; return *", 2, 3))
  tcheck(t, {n=4,2,3})
  
  t = pack(T.testC("settop 0; settop 15; return 10", 3, 1, 23))
  assert(t.n == 10 and t[1] == nil and t[10] == nil)
  
  t = pack(T.testC("remove -2; return *", 2, 3, 4))
  tcheck(t, {n=2,2,4})
  
  t = pack(T.testC("insert -1; return *", 2, 3))
  tcheck(t, {n=2,2,3})
  
  t = pack(T.testC("insert 3; return *", 2, 3, 4, 5))
  tcheck(t, {n=4,2,5,3,4})
  
  t = pack(T.testC("replace 2; return *", 2, 3, 4, 5))
  tcheck(t, {n=3,5,3,4})
  
  t = pack(T.testC("replace -2; return *", 2, 3, 4, 5))
  tcheck(t, {n=3,2,3,5})
  
  t = pack(T.testC("remove 3; return *", 2, 3, 4, 5))
  tcheck(t, {n=3,2,4,5})
  
  t = pack(T.testC("copy 3 4; return *", 2, 3, 4, 5))
  tcheck(t, {n=4,2,3,3,5})
  
  t = pack(T.testC("copy -3 -1; return *", 2, 3, 4, 5))
  tcheck(t, {n=4,2,3,4,3})
  
  do   -- testing 'rotate'
    local t = {10, 20, 30, 40, 50, 60}
    for i = -6, 6 do
      local s = string.format("rotate 2 %d; return 7", i)
      local t1 = pack(T.testC(s, 10, 20, 30, 40, 50, 60))
      tcheck(t1, t)
      table.insert(t, 1, table.remove(t))
    end
  
    t = pack(T.testC("rotate -2 1; return *", 10, 20, 30, 40))
    tcheck(t, {10, 20, 40, 30})
    t = pack(T.testC("rotate -2 -1; return *", 10, 20, 30, 40))
    tcheck(t, {10, 20, 40, 30})
  
    -- some corner cases
    t = pack(T.testC("rotate -1 0; return *", 10, 20, 30, 40))
    tcheck(t, {10, 20, 30, 40})
    t = pack(T.testC("rotate -1 1; return *", 10, 20, 30, 40))
    tcheck(t, {10, 20, 30, 40})
    t = pack(T.testC("rotate 5 -1; return *", 10, 20, 30, 40))
    tcheck(t, {10, 20, 30, 40})
  end
  
  
  -- testing warnings
  T.testC([[
    warningC "#This shold be a"
    warningC " single "
    warning "warning"
    warningC "#This should be "
    warning "another one"
  ]])
  
  
  -- testing message handlers
  do
    local f = T.makeCfunc[[
      getglobal error
      pushstring bola
      pcall 1 1 1   # call 'error' with given handler
      pushstatus
      return 2     # return error message and status
    ]]
  
    local msg, st = f(string.upper)   -- function handler
    assert(st == "ERRRUN" and msg == "BOLA")
    local msg, st = f(string.len)     -- function handler
    assert(st == "ERRRUN" and msg == 4)
  
  end
  
  t = pack(T.testC("insert 3; pushvalue 3; remove 3; pushvalue 2; remove 2; \
                    insert 2; pushvalue 1; remove 1; insert 1; \
        insert -2; pushvalue -2; remove -3; return *",
        2, 3, 4, 5, 10, 40, 90))
  tcheck(t, {n=7,2,3,4,5,10,40,90})
  
  t = pack(T.testC("concat 5; return *", "alo", 2, 3, "joao", 12))
  tcheck(t, {n=1,"alo23joao12"})
  
  -- testing MULTRET
  t = pack(T.testC("call 2,-1; return *",
       function (a,b) return 1,2,3,4,a,b end, "alo", "joao"))
  tcheck(t, {n=6,1,2,3,4,"alo", "joao"})
  
  do  -- test returning more results than fit in the caller stack
    local a = {}
    for i=1,1000 do a[i] = true end; a[999] = 10
    local b = T.testC([[pcall 1 -1 0; pop 1; tostring -1; return 1]],
                      table.unpack, a)
    assert(b == "10")
  end
  
  
  -- testing globals
  _G.a = 14; _G.b = "a31"
  local a = {T.testC[[
    getglobal a;
    getglobal b;
    getglobal b;
    setglobal a;
    return *
  ]]}
  assert(a[2] == 14 and a[3] == "a31" and a[4] == nil and _G.a == "a31")
  
  
  -- testing arith
  assert(T.testC("pushnum 10; pushnum 20; arith /; return 1") == 0.5)
  assert(T.testC("pushnum 10; pushnum 20; arith -; return 1") == -10)
  assert(T.testC("pushnum 10; pushnum -20; arith *; return 1") == -200)
  assert(T.testC("pushnum 10; pushnum 3; arith ^; return 1") == 1000)
  assert(T.testC("pushnum 10; pushstring 20; arith /; return 1") == 0.5)
  assert(T.testC("pushstring 10; pushnum 20; arith -; return 1") == -10)
  assert(T.testC("pushstring 10; pushstring -20; arith *; return 1") == -200)
  assert(T.testC("pushstring 10; pushstring 3; arith ^; return 1") == 1000)
  assert(T.testC("arith /; return 1", 2, 0) == 10.0/0)
  a = T.testC("pushnum 10; pushint 3; arith \\; return 1")
  assert(a == 3.0 and math.type(a) == "float")
  a = T.testC("pushint 10; pushint 3; arith \\; return 1")
  assert(a == 3 and math.type(a) == "integer")
  a = assert(T.testC("pushint 10; pushint 3; arith +; return 1"))
  assert(a == 13 and math.type(a) == "integer")
  a = assert(T.testC("pushnum 10; pushint 3; arith +; return 1"))
  assert(a == 13 and math.type(a) == "float")
  a,b,c = T.testC([[pushnum 1;
                    pushstring 10; arith _;
                    pushstring 5; return 3]])
  assert(a == 1 and b == -10 and c == "5")
  mt = {__add = function (a,b) return setmetatable({a[1] + b[1]}, mt) end,
        __mod = function (a,b) return setmetatable({a[1] % b[1]}, mt) end,
        __unm = function (a) return setmetatable({a[1]* 2}, mt) end}
  a,b,c = setmetatable({4}, mt),
          setmetatable({8}, mt),
          setmetatable({-3}, mt)
  x,y,z = T.testC("arith +; return 2", 10, a, b)
  assert(x == 10 and y[1] == 12 and z == nil)
  assert(T.testC("arith %; return 1", a, c)[1] == 4%-3)
  assert(T.testC("arith _; arith +; arith %; return 1", b, a, c)[1] ==
                 8 % (4 + (-3)*2))
  
  -- errors in arithmetic
  checkerr("divide by zero", T.testC, "arith \\", 10, 0)
  checkerr("%%0", T.testC, "arith %", 10, 0)
  
  
  -- testing lessthan and lessequal
  assert(T.testC("compare LT 2 5, return 1", 3, 2, 2, 4, 2, 2))
  assert(T.testC("compare LE 2 5, return 1", 3, 2, 2, 4, 2, 2))
  assert(not T.testC("compare LT 3 4, return 1", 3, 2, 2, 4, 2, 2))
  assert(T.testC("compare LE 3 4, return 1", 3, 2, 2, 4, 2, 2))
  assert(T.testC("compare LT 5 2, return 1", 4, 2, 2, 3, 2, 2))
  assert(not T.testC("compare LT 2 -3, return 1", "4", "2", "2", "3", "2", "2"))
  assert(not T.testC("compare LT -3 2, return 1", "3", "2", "2", "4", "2", "2"))
  
  -- non-valid indices produce false
  assert(not T.testC("compare LT 1 4, return 1"))
  assert(not T.testC("compare LE 9 1, return 1"))
  assert(not T.testC("compare EQ 9 9, return 1"))
  
  local b = {__lt = function (a,b) return a[1] < b[1] end}
  local a1,a3,a4 = setmetatable({1}, b),
                   setmetatable({3}, b),
                   setmetatable({4}, b)
  assert(T.testC("compare LT 2 5, return 1", a3, 2, 2, a4, 2, 2))
  assert(T.testC("compare LE 2 5, return 1", a3, 2, 2, a4, 2, 2))
  assert(T.testC("compare LT 5 -6, return 1", a4, 2, 2, a3, 2, 2))
  a,b = T.testC("compare LT 5 -6, return 2", a1, 2, 2, a3, 2, 20)
  assert(a == 20 and b == false)
  a,b = T.testC("compare LE 5 -6, return 2", a1, 2, 2, a3, 2, 20)
  assert(a == 20 and b == false)
  a,b = T.testC("compare LE 5 -6, return 2", a1, 2, 2, a1, 2, 20)
  assert(a == 20 and b == true)
  
  
  do  -- testing lessthan and lessequal with metamethods
    local mt = {__lt = function (a,b) return a[1] < b[1] end,
                __le = function (a,b) return a[1] <= b[1] end,
                __eq = function (a,b) return a[1] == b[1] end}
    local function O (x)
      return setmetatable({x}, mt)
    end
  
    local a, b = T.testC("compare LT 2 3; pushint 10; return 2", O(1), O(2))
    assert(a == true and b == 10)
    local a, b = T.testC("compare LE 2 3; pushint 10; return 2", O(3), O(2))
    assert(a == false and b == 10)
    local a, b = T.testC("compare EQ 2 3; pushint 10; return 2", O(3), O(3))
    assert(a == true and b == 10)
  end
  
  -- testing length
  local t = setmetatable({x = 20}, {__len = function (t) return t.x end})
  a,b,c = T.testC([[
     len 2;
     Llen 2;
     objsize 2;
     return 3
  ]], t)
  assert(a == 20 and b == 20 and c == 0)
  
  t.x = "234"; t[1] = 20
  a,b,c = T.testC([[
     len 2;
     Llen 2;
     objsize 2;
     return 3
  ]], t)
  assert(a == "234" and b == 234 and c == 1)
  
  t.x = print; t[1] = 20
  a,c = T.testC([[
     len 2;
     objsize 2;
     return 2
  ]], t)
  assert(a == print and c == 1)
  
  
  -- testing __concat
  
  a = setmetatable({x="u"}, {__concat = function (a,b) return a.x..'.'..b.x end})
  x,y = T.testC([[
    pushnum 5
    pushvalue 2;
    pushvalue 2;
    concat 2;
    pushvalue -2;
    return 2;
  ]], a, a)
  assert(x == a..a and y == 5)
  
  -- concat with 0 elements
  assert(T.testC("concat 0; return 1") == "")
  
  -- concat with 1 element
  assert(T.testC("concat 1; return 1", "xuxu") == "xuxu")
  
  
  
  -- testing lua_is
  
  function B(x) return x and 1 or 0 end
  
  function count (x, n)
    n = n or 2
    local prog = [[
      isnumber %d;
      isstring %d;
      isfunction %d;
      iscfunction %d;
      istable %d;
      isuserdata %d;
      isnil %d;
      isnull %d;
      return 8
    ]]
    prog = string.format(prog, n, n, n, n, n, n, n, n)
    local a,b,c,d,e,f,g,h = T.testC(prog, x)
    return B(a)+B(b)+B(c)+B(d)+B(e)+B(f)+B(g)+(100*B(h))
  end
  
  assert(count(3) == 2)
  assert(count('alo') == 1)
  assert(count('32') == 2)
  assert(count({}) == 1)
  assert(count(print) == 2)
  assert(count(function () end) == 1)
  assert(count(nil) == 1)
  assert(count(io.stdin) == 1)
  assert(count(nil, 15) == 100)
  
  
  -- testing lua_to...
  
  function to (s, x, n)
    n = n or 2
    return T.testC(string.format("%s %d; return 1", s, n), x)
  end
  
  local null = T.pushuserdata(0)
  local hfunc = string.gmatch("", "")    -- a "heavy C function" (with upvalues)
  assert(debug.getupvalue(hfunc, 1))
  assert(to("tostring", {}) == nil)
  assert(to("tostring", "alo") == "alo")
  assert(to("tostring", 12) == "12")
  assert(to("tostring", 12, 3) == nil)
  assert(to("objsize", {}) == 0)
  assert(to("objsize", {1,2,3}) == 3)
  assert(to("objsize", "alo\0\0a") == 6)
  assert(to("objsize", T.newuserdata(0)) == 0)
  assert(to("objsize", T.newuserdata(101)) == 101)
  assert(to("objsize", 124) == 0)
  assert(to("objsize", true) == 0)
  assert(to("tonumber", {}) == 0)
  assert(to("tonumber", "12") == 12)
  assert(to("tonumber", "s2") == 0)
  assert(to("tonumber", 1, 20) == 0)
  assert(to("topointer", 10) == null)
  assert(to("topointer", true) == null)
  assert(to("topointer", nil) == null)
  assert(to("topointer", "abc") ~= null)
  assert(to("topointer", string.rep("x", 10)) ==
         to("topointer", string.rep("x", 10)))    -- short strings
  do    -- long strings
    local s1 = string.rep("x", 300)
    local s2 = string.rep("x", 300)
    assert(to("topointer", s1) ~= to("topointer", s2))
  end
  assert(to("topointer", T.pushuserdata(20)) ~= null)
  assert(to("topointer", io.read) ~= null)           -- light C function
  assert(to("topointer", hfunc) ~= null)        -- "heavy" C function
  assert(to("topointer", function () end) ~= null)   -- Lua function
  assert(to("topointer", io.stdin) ~= null)   -- full userdata
  assert(to("func2num", 20) == 0)
  assert(to("func2num", T.pushuserdata(10)) == 0)
  assert(to("func2num", io.read) ~= 0)     -- light C function
  assert(to("func2num", hfunc) ~= 0)  -- "heavy" C function (with upvalue)
  a = to("tocfunction", math.deg)
  assert(a(3) == math.deg(3) and a == math.deg)
  
  
  print("testing panic function")
  do
    -- trivial error
    assert(T.checkpanic("pushstring hi; error") == "hi")
  
    -- using the stack inside panic
    assert(T.checkpanic("pushstring hi; error;",
      [[checkstack 5 XX
        pushstring ' alo'
        pushstring ' mundo'
        concat 3]]) == "hi alo mundo")
  
    -- "argerror" without frames
    assert(T.checkpanic("loadstring 4") ==
        "bad argument #4 (string expected, got no value)")
  
  
    -- memory error
    T.totalmem(T.totalmem()+10000)   -- set low memory limit (+10k)
    assert(T.checkpanic("newuserdata 20000") == MEMERRMSG)
    T.totalmem(0)          -- restore high limit
  
    -- stack error
    if not _soft then
      local msg = T.checkpanic[[
        pushstring "function f() f() end"
        loadstring -1; call 0 0
        getglobal f; call 0 0
      ]]
      assert(string.find(msg, "stack overflow"))
    end
  
    -- exit in panic still close to-be-closed variables
    assert(T.checkpanic([[
      pushstring "return {__close = function () Y = 'ho'; end}"
      newtable
      loadstring -2
      call 0 1
      setmetatable -2
      toclose -1
      pushstring "hi"
      error
    ]],
    [[
      getglobal Y
      concat 2         # concat original error with global Y
    ]]) == "hiho")
  
  
  end
  
  -- testing deep C stack
  if not _soft then
    print("testing stack overflow")
    collectgarbage("stop")
    checkerr("XXXX", T.testC, "checkstack 1000023 XXXX")   -- too deep
    -- too deep (with no message)
    checkerr("^stack overflow$", T.testC, "checkstack 1000023 ''")
    local s = string.rep("pushnil;checkstack 1 XX;", 1000000)
    checkerr("overflow", T.testC, s)
    collectgarbage("restart")
    print'+'
  end
  
  local lim = _soft and 500 or 12000
  local prog = {"checkstack " .. (lim * 2 + 100) .. "msg", "newtable"}
  for i = 1,lim do
    prog[#prog + 1] = "pushnum " .. i
    prog[#prog + 1] = "pushnum " .. i * 10
  end
  
  prog[#prog + 1] = "rawgeti R 2"   -- get global table in registry
  prog[#prog + 1] = "insert " .. -(2*lim + 2)
  
  for i = 1,lim do
    prog[#prog + 1] = "settable " .. -(2*(lim - i + 1) + 1)
  end
  
  prog[#prog + 1] = "return 2"
  
  prog = table.concat(prog, ";")
  local g, t = T.testC(prog)
  assert(g == _G)
  for i = 1,lim do assert(t[i] == i*10); t[i] = undef end
  assert(next(t) == nil)
  prog, g, t = nil
  
  -- testing errors
  
  a = T.testC([[
    loadstring 2; pcall 0 1 0;
    pushvalue 3; insert -2; pcall 1 1 0;
    pcall 0 0 0;
    return 1
  ]], "x=150", function (a) assert(a==nil); return 3 end)
  
  assert(type(a) == 'string' and x == 150)
  
  function check3(p, ...)
    local arg = {...}
    assert(#arg == 3)
    assert(string.find(arg[3], p))
  end
  check3(":1:", T.testC("loadstring 2; return *", "x="))
  check3("%.", T.testC("loadfile 2; return *", "."))
  check3("xxxx", T.testC("loadfile 2; return *", "xxxx"))
  
  -- test errors in non protected threads
  function checkerrnopro (code, msg)
    local th = coroutine.create(function () end)  -- create new thread
    local stt, err = pcall(T.testC, th, code)   -- run code there
    assert(not stt and string.find(err, msg))
  end
  
  if not _soft then
    collectgarbage("stop")   -- avoid __gc with full stack
    checkerrnopro("pushnum 3; call 0 0", "attempt to call")
    print"testing stack overflow in unprotected thread"
    function f () f() end
    checkerrnopro("getglobal 'f'; call 0 0;", "stack overflow")
    collectgarbage("restart")
  end
  print"+"
  
  
  -- testing table access
  
  do   -- getp/setp
    local a = {}
    local a1 = T.testC("rawsetp 2 1; return 1", a, 20)
    assert(a == a1)
    assert(a[T.pushuserdata(1)] == 20)
    local a1, res = T.testC("rawgetp -1 1; return 2", a)
    assert(a == a1 and res == 20)
  end
  
  
  do  -- using the table itself as index
    local a = {}
    a[a] = 10
    local prog = "gettable -1; return *"
    local res = {T.testC(prog, a)}
    assert(#res == 2 and res[1] == prog and res[2] == 10)
  
    local prog = "settable -2; return *"
    local res = {T.testC(prog, a, 20)}
    assert(a[a] == 20)
    assert(#res == 1 and res[1] == prog)
  
    -- raw
    a[a] = 10
    local prog = "rawget -1; return *"
    local res = {T.testC(prog, a)}
    assert(#res == 2 and res[1] == prog and res[2] == 10)
  
    local prog = "rawset -2; return *"
    local res = {T.testC(prog, a, 20)}
    assert(a[a] == 20)
    assert(#res == 1 and res[1] == prog)
  
    -- using the table as the value to set
    local prog = "rawset -1; return *"
    local res = {T.testC(prog, 30, a)}
    assert(a[30] == a)
    assert(#res == 1 and res[1] == prog)
  
    local prog = "settable -1; return *"
    local res = {T.testC(prog, 40, a)}
    assert(a[40] == a)
    assert(#res == 1 and res[1] == prog)
  
    local prog = "rawseti -1 100; return *"
    local res = {T.testC(prog, a)}
    assert(a[100] == a)
    assert(#res == 1 and res[1] == prog)
  
    local prog = "seti -1 200; return *"
    local res = {T.testC(prog, a)}
    assert(a[200] == a)
    assert(#res == 1 and res[1] == prog)
  end
  
  a = {x=0, y=12}
  x, y = T.testC("gettable 2; pushvalue 4; gettable 2; return 2",
                  a, 3, "y", 4, "x")
  assert(x == 0 and y == 12)
  T.testC("settable -5", a, 3, 4, "x", 15)
  assert(a.x == 15)
  a[a] = print
  x = T.testC("gettable 2; return 1", a)  -- table and key are the same object!
  assert(x == print)
  T.testC("settable 2", a, "x")    -- table and key are the same object!
  assert(a[a] == "x")
  
  b = setmetatable({p = a}, {})
  getmetatable(b).__index = function (t, i) return t.p[i] end
  k, x = T.testC("gettable 3, return 2", 4, b, 20, 35, "x")
  assert(x == 15 and k == 35)
  k = T.testC("getfield 2 y, return 1", b)
  assert(k == 12)
  getmetatable(b).__index = function (t, i) return a[i] end
  getmetatable(b).__newindex = function (t, i,v ) a[i] = v end
  y = T.testC("insert 2; gettable -5; return 1", 2, 3, 4, "y", b)
  assert(y == 12)
  k = T.testC("settable -5, return 1", b, 3, 4, "x", 16)
  assert(a.x == 16 and k == 4)
  a[b] = 'xuxu'
  y = T.testC("gettable 2, return 1", b)
  assert(y == 'xuxu')
  T.testC("settable 2", b, 19)
  assert(a[b] == 19)
  
  --
  do   -- testing getfield/setfield with long keys
    local t = {_012345678901234567890123456789012345678901234567890123456789 = 32}
    local a = T.testC([[
      getfield 2 _012345678901234567890123456789012345678901234567890123456789
      return 1
    ]], t)
    assert(a == 32)
    local a = T.testC([[
      pushnum 33
      setglobal _012345678901234567890123456789012345678901234567890123456789
    ]])
    assert(_012345678901234567890123456789012345678901234567890123456789 == 33)
    _012345678901234567890123456789012345678901234567890123456789 = nil
  end
  
  -- testing next
  a = {}
  t = pack(T.testC("next; return *", a, nil))
  tcheck(t, {n=1,a})
  a = {a=3}
  t = pack(T.testC("next; return *", a, nil))
  tcheck(t, {n=3,a,'a',3})
  t = pack(T.testC("next; pop 1; next; return *", a, nil))
  tcheck(t, {n=1,a})
  
  
  
  -- testing upvalues
  
  do
    local A = T.testC[[ pushnum 10; pushnum 20; pushcclosure 2; return 1]]
    t, b, c = A([[pushvalue U0; pushvalue U1; pushvalue U2; return 3]])
    assert(b == 10 and c == 20 and type(t) == 'table')
    a, b = A([[tostring U3; tonumber U4; return 2]])
    assert(a == nil and b == 0)
    A([[pushnum 100; pushnum 200; replace U2; replace U1]])
    b, c = A([[pushvalue U1; pushvalue U2; return 2]])
    assert(b == 100 and c == 200)
    A([[replace U2; replace U1]], {x=1}, {x=2})
    b, c = A([[pushvalue U1; pushvalue U2; return 2]])
    assert(b.x == 1 and c.x == 2)
    T.checkmemory()
  end
  
  
  -- testing absent upvalues from C-function pointers
  assert(T.testC[[isnull U1; return 1]] == true)
  assert(T.testC[[isnull U100; return 1]] == true)
  assert(T.testC[[pushvalue U1; return 1]] == nil)
  
  local f = T.testC[[ pushnum 10; pushnum 20; pushcclosure 2; return 1]]
  assert(T.upvalue(f, 1) == 10 and
         T.upvalue(f, 2) == 20 and
         T.upvalue(f, 3) == nil)
  T.upvalue(f, 2, "xuxu")
  assert(T.upvalue(f, 2) == "xuxu")
  
  
  -- large closures
  do
    local A = "checkstack 300 msg;" ..
              string.rep("pushnum 10;", 255) ..
              "pushcclosure 255; return 1"
    A = T.testC(A)
    for i=1,255 do
      assert(A(("pushvalue U%d; return 1"):format(i)) == 10)
    end
    assert(A("isnull U256; return 1"))
    assert(not A("isnil U256; return 1"))
  end
  
  
  
  -- testing get/setuservalue
  -- bug in 5.1.2
  checkerr("got number", debug.setuservalue, 3, {})
  checkerr("got nil", debug.setuservalue, nil, {})
  checkerr("got light userdata", debug.setuservalue, T.pushuserdata(1), {})
  
  -- testing multiple user values
  local b = T.newuserdata(0, 10)
  for i = 1, 10 do
    local v, p = debug.getuservalue(b, i)
    assert(v == nil and p)
  end
  do   -- indices out of range
    local v, p = debug.getuservalue(b, -2)
    assert(v == nil and not p)
    local v, p = debug.getuservalue(b, 11)
    assert(v == nil and not p)
  end
  local t = {true, false, 4.56, print, {}, b, "XYZ"}
  for k, v in ipairs(t) do
    debug.setuservalue(b, v, k)
  end
  for k, v in ipairs(t) do
    local v1, p = debug.getuservalue(b, k)
    assert(v1 == v and p)
  end
  
  assert(not debug.getuservalue(4))
  
  debug.setuservalue(b, function () return 10 end, 10)
  collectgarbage()   -- function should not be collected
  assert(debug.getuservalue(b, 10)() == 10)
  
  debug.setuservalue(b, 134)
  collectgarbage()   -- number should not be a problem for collector
  assert(debug.getuservalue(b) == 134)
  
  
  -- test barrier for uservalues
  do
    local oldmode = collectgarbage("incremental")
    T.gcstate("atomic")
    assert(T.gccolor(b) == "black")
    debug.setuservalue(b, {x = 100})
    T.gcstate("pause")  -- complete collection
    assert(debug.getuservalue(b).x == 100)  -- uvalue should be there
    collectgarbage(oldmode)
  end
  
  -- long chain of userdata
  for i = 1, 1000 do
    local bb = T.newuserdata(0, 1)
    debug.setuservalue(bb, b)
    b = bb
  end
  collectgarbage()     -- nothing should not be collected
  for i = 1, 1000 do
    b = debug.getuservalue(b)
  end
  assert(debug.getuservalue(b).x == 100)
  b = nil
  
  
  -- testing locks (refs)
  
  -- reuse of references
  local i = T.ref{}
  T.unref(i)
  assert(T.ref{} == i)
  
  Arr = {}
  Lim = 100
  for i=1,Lim do   -- lock many objects
    Arr[i] = T.ref({})
  end
  
  assert(T.ref(nil) == -1 and T.getref(-1) == nil)
  T.unref(-1); T.unref(-1)
  
  for i=1,Lim do   -- unlock all them
    T.unref(Arr[i])
  end
  
  function printlocks ()
    local f = T.makeCfunc("gettable R; return 1")
    local n = f("n")
    print("n", n)
    for i=0,n do
      print(i, f(i))
    end
  end
  
  
  for i=1,Lim do   -- lock many objects
    Arr[i] = T.ref({})
  end
  
  for i=1,Lim,2 do   -- unlock half of them
    T.unref(Arr[i])
  end
  
  assert(type(T.getref(Arr[2])) == 'table')
  
  
  assert(T.getref(-1) == nil)
  
  
  a = T.ref({})
  
  collectgarbage()
  
  assert(type(T.getref(a)) == 'table')
  
  
  -- colect in cl the `val' of all collected userdata
  tt = {}
  cl = {n=0}
  A = nil; B = nil
  local F
  F = function (x)
    local udval = T.udataval(x)
    table.insert(cl, udval)
    local d = T.newuserdata(100)   -- create garbage
    d = nil
    assert(debug.getmetatable(x).__gc == F)
    assert(load("table.insert({}, {})"))()   -- create more garbage
    collectgarbage()   -- force a GC during GC
    assert(debug.getmetatable(x).__gc == F)  -- previous GC did not mess this?
    local dummy = {}    -- create more garbage during GC
    if A ~= nil then
      assert(type(A) == "userdata")
      assert(T.udataval(A) == B)
      debug.getmetatable(A)    -- just access it
    end
    A = x   -- ressucita userdata
    B = udval
    return 1,2,3
  end
  tt.__gc = F
  
  -- test whether udate collection frees memory in the right time
  do
    collectgarbage();
    collectgarbage();
    local x = collectgarbage("count");
    local a = T.newuserdata(5001)
    assert(T.testC("objsize 2; return 1", a) == 5001)
    assert(collectgarbage("count") >= x+4)
    a = nil
    collectgarbage();
    assert(collectgarbage("count") <= x+1)
    -- udata without finalizer
    x = collectgarbage("count")
    collectgarbage("stop")
    for i=1,1000 do T.newuserdata(0) end
    assert(collectgarbage("count") > x+10)
    collectgarbage()
    assert(collectgarbage("count") <= x+1)
    -- udata with finalizer
    collectgarbage()
    x = collectgarbage("count")
    collectgarbage("stop")
    a = {__gc = function () end}
    for i=1,1000 do debug.setmetatable(T.newuserdata(0), a) end
    assert(collectgarbage("count") >= x+10)
    collectgarbage()  -- this collection only calls TM, without freeing memory
    assert(collectgarbage("count") >= x+10)
    collectgarbage()  -- now frees memory
    assert(collectgarbage("count") <= x+1)
    collectgarbage("restart")
  end
  
  
  collectgarbage("stop")
  
  -- create 3 userdatas with tag `tt'
  a = T.newuserdata(0); debug.setmetatable(a, tt); na = T.udataval(a)
  b = T.newuserdata(0); debug.setmetatable(b, tt); nb = T.udataval(b)
  c = T.newuserdata(0); debug.setmetatable(c, tt); nc = T.udataval(c)
  
  -- create userdata without meta table
  x = T.newuserdata(4)
  y = T.newuserdata(0)
  
  checkerr("FILE%* expected, got userdata", io.input, a)
  checkerr("FILE%* expected, got userdata", io.input, x)
  
  assert(debug.getmetatable(x) == nil and debug.getmetatable(y) == nil)
  
  d=T.ref(a);
  e=T.ref(b);
  f=T.ref(c);
  t = {T.getref(d), T.getref(e), T.getref(f)}
  assert(t[1] == a and t[2] == b and t[3] == c)
  
  t=nil; a=nil; c=nil;
  T.unref(e); T.unref(f)
  
  collectgarbage()
  
  -- check that unref objects have been collected
  assert(#cl == 1 and cl[1] == nc)
  
  x = T.getref(d)
  assert(type(x) == 'userdata' and debug.getmetatable(x) == tt)
  x =nil
  tt.b = b  -- create cycle
  tt=nil    -- frees tt for GC
  A = nil
  b = nil
  T.unref(d);
  n5 = T.newuserdata(0)
  debug.setmetatable(n5, {__gc=F})
  n5 = T.udataval(n5)
  collectgarbage()
  assert(#cl == 4)
  -- check order of collection
  assert(cl[2] == n5 and cl[3] == nb and cl[4] == na)
  
  collectgarbage"restart"
  
  
  a, na = {}, {}
  for i=30,1,-1 do
    a[i] = T.newuserdata(0)
    debug.setmetatable(a[i], {__gc=F})
    na[i] = T.udataval(a[i])
  end
  cl = {}
  a = nil; collectgarbage()
  assert(#cl == 30)
  for i=1,30 do assert(cl[i] == na[i]) end
  na = nil
  
  
  for i=2,Lim,2 do   -- unlock the other half
    T.unref(Arr[i])
  end
  
  x = T.newuserdata(41); debug.setmetatable(x, {__gc=F})
  assert(T.testC("objsize 2; return 1", x) == 41)
  cl = {}
  a = {[x] = 1}
  x = T.udataval(x)
  collectgarbage()
  -- old `x' cannot be collected (`a' still uses it)
  assert(#cl == 0)
  for n in pairs(a) do a[n] = undef end
  collectgarbage()
  assert(#cl == 1 and cl[1] == x)   -- old `x' must be collected
  
  -- testing lua_equal
  assert(T.testC("compare EQ 2 4; return 1", print, 1, print, 20))
  assert(T.testC("compare EQ 3 2; return 1", 'alo', "alo"))
  assert(T.testC("compare EQ 2 3; return 1", nil, nil))
  assert(not T.testC("compare EQ 2 3; return 1", {}, {}))
  assert(not T.testC("compare EQ 2 3; return 1"))
  assert(not T.testC("compare EQ 2 3; return 1", 3))
  
  -- testing lua_equal with fallbacks
  do
    local map = {}
    local t = {__eq = function (a,b) return map[a] == map[b] end}
    local function f(x)
      local u = T.newuserdata(0)
      debug.setmetatable(u, t)
      map[u] = x
      return u
    end
    assert(f(10) == f(10))
    assert(f(10) ~= f(11))
    assert(T.testC("compare EQ 2 3; return 1", f(10), f(10)))
    assert(not T.testC("compare EQ 2 3; return 1", f(10), f(20)))
    t.__eq = nil
    assert(f(10) ~= f(10))
  end
  
  print'+'
  
  
  
  -- testing changing hooks during hooks
  _G.t = {}
  T.sethook([[
    # set a line hook after 3 count hooks
    sethook 4 0 '
      getglobal t;
      pushvalue -3; append -2
      pushvalue -2; append -2
    ']], "c", 3)
  local a = 1   -- counting
  a = 1   -- counting
  a = 1   -- count hook (set line hook)
  a = 1   -- line hook
  a = 1   -- line hook
  debug.sethook()
  t = _G.t
  assert(t[1] == "line")
  line = t[2]
  assert(t[3] == "line" and t[4] == line + 1)
  assert(t[5] == "line" and t[6] == line + 2)
  assert(t[7] == nil)
  
  
  -------------------------------------------------------------------------
  do   -- testing errors during GC
    warn("@off")
    collectgarbage("stop")
    local a = {}
    for i=1,20 do
      a[i] = T.newuserdata(i)   -- creates several udata
    end
    for i=1,20,2 do   -- mark half of them to raise errors during GC
      debug.setmetatable(a[i],
        {__gc = function (x) error("@expected error in gc") end})
    end
    for i=2,20,2 do   -- mark the other half to count and to create more garbage
      debug.setmetatable(a[i], {__gc = function (x) load("A=A+1")() end})
    end
    a = nil
    _G.A = 0
    collectgarbage()
    assert(A == 10)  -- number of normal collections
    collectgarbage("restart")
    warn("@on")
  end
  -------------------------------------------------------------------------
  -- test for userdata vals
  do
    local a = {}; local lim = 30
    for i=0,lim do a[i] = T.pushuserdata(i) end
    for i=0,lim do assert(T.udataval(a[i]) == i) end
    for i=0,lim do assert(T.pushuserdata(i) == a[i]) end
    for i=0,lim do a[a[i]] = i end
    for i=0,lim do a[T.pushuserdata(i)] = i end
    assert(type(tostring(a[1])) == "string")
  end
  
  
  -------------------------------------------------------------------------
  -- testing multiple states
  T.closestate(T.newstate());
  L1 = T.newstate()
  assert(L1)
  
  assert(T.doremote(L1, "X='a'; return 'a'") == 'a')
  
  
  assert(#pack(T.doremote(L1, "function f () return 'alo', 3 end; f()")) == 0)
  
  a, b = T.doremote(L1, "return f()")
  assert(a == 'alo' and b == '3')
  
  T.doremote(L1, "_ERRORMESSAGE = nil")
  -- error: `sin' is not defined
  a, _, b = T.doremote(L1, "return sin(1)")
  assert(a == nil and b == 2)   -- 2 == run-time error
  
  -- error: syntax error
  a, b, c = T.doremote(L1, "return a+")
  assert(a == nil and c == 3 and type(b) == "string")   -- 3 == syntax error
  
  T.loadlib(L1)
  a, b, c = T.doremote(L1, [[
    string = require'string'
    a = require'_G'; assert(a == _G and require("_G") == a)
    io = require'io'; assert(type(io.read) == "function")
    assert(require("io") == io)
    a = require'table'; assert(type(a.insert) == "function")
    a = require'debug'; assert(type(a.getlocal) == "function")
    a = require'math'; assert(type(a.sin) == "function")
    return string.sub('okinama', 1, 2)
  ]])
  assert(a == "ok")
  
  T.closestate(L1);
  
  
  L1 = T.newstate()
  T.loadlib(L1)
  T.doremote(L1, "a = {}")
  T.testC(L1, [[getglobal "a"; pushstring "x"; pushint 1;
               settable -3]])
  assert(T.doremote(L1, "return a.x") == "1")
  
  T.closestate(L1)
  
  L1 = nil
  
  print('+')
  -------------------------------------------------------------------------
  -- testing to-be-closed variables
  -------------------------------------------------------------------------
  print"testing to-be-closed variables"
  
  do
    local openresource = {}
  
    local function newresource ()
      local x = setmetatable({10}, {__close = function(y)
        assert(openresource[#openresource] == y)
        openresource[#openresource] = nil
        y[1] = y[1] + 1
      end})
      openresource[#openresource + 1] = x
      return x
    end
  
    local a, b = T.testC([[
      call 0 1   # create resource
      pushnil
      toclose -2  # mark call result to be closed
      toclose -1  # mark nil to be closed (will be ignored)
      return 2
    ]], newresource)
    assert(a[1] == 11 and b == nil)
    assert(#openresource == 0)    -- was closed
  
    -- repeat the test, but calling function in a 'multret' context
    local a = {T.testC([[
      call 0 1   # create resource
      toclose 2 # mark it to be closed
      return 2
    ]], newresource)}
    assert(type(a[1]) == "string" and a[2][1] == 11)
    assert(#openresource == 0)    -- was closed
  
    -- closing by error
    local a, b = pcall(T.makeCfunc[[
      call 0 1   # create resource
      toclose -1 # mark it to be closed
      error       # resource is the error object
    ]], newresource)
    assert(a == false and b[1] == 11)
    assert(#openresource == 0)    -- was closed
  
    -- non-closable value
    local a, b = pcall(T.makeCfunc[[
      newtable   # create non-closable object
      toclose -1 # mark it to be closed (should raise an error)
      abort  # will not be executed
    ]])
    assert(a == false and
      string.find(b, "non%-closable value"))
  
    local function check (n)
      assert(#openresource == n)
    end
  
    -- closing resources with 'closeslot'
    _ENV.xxx = true
    local a = T.testC([[
      pushvalue 2  # stack: S, NR, CH, NR
      call 0 1   # create resource; stack: S, NR, CH, R
      toclose -1 # mark it to be closed
      pushvalue 2  #  stack: S, NR, CH, R, NR
      call 0 1   # create another resource; stack: S, NR, CH, R, R
      toclose -1 # mark it to be closed
      pushvalue 3  # stack: S, NR, CH, R, R, CH
      pushint 2   # there should be two open resources
      call 1 0  #  stack: S, NR, CH, R, R
      closeslot -1   # close second resource
      pushvalue 3  # stack: S, NR, CH, R, R, CH
      pushint 1   # there should be one open resource
      call 1 0  # stack: S, NR, CH, R, R
      closeslot 4
      setglobal "xxx"  # previous op. erased the slot
      pop 1       # pop other resource from the stack
      pushint *
      return 1    # return stack size
    ]], newresource, check)
    assert(a == 3 and _ENV.xxx == nil)   -- no extra items left in the stack
  
    -- closing resources with 'pop'
    local a = T.testC([[
      pushvalue 2  # stack: S, NR, CH, NR
      call 0 1   # create resource; stack: S, NR, CH, R
      toclose -1 # mark it to be closed
      pushvalue 2  #  stack: S, NR, CH, R, NR
      call 0 1   # create another resource; stack: S, NR, CH, R, R
      toclose -1 # mark it to be closed
      pushvalue 3  # stack: S, NR, CH, R, R, CH
      pushint 2   # there should be two open resources
      call 1 0  #  stack: S, NR, CH, R, R
      pop 1   # pop second resource
      pushvalue 3  # stack: S, NR, CH, R, CH
      pushint 1   # there should be one open resource
      call 1 0  # stack: S, NR, CH, R
      pop 1       # pop other resource from the stack
      pushvalue 3  # stack: S, NR, CH, CH
      pushint 0   # there should be no open resources
      call 1 0  # stack: S, NR, CH
      pushint *
      return 1    # return stack size
    ]], newresource, check)
    assert(a == 3)   -- no extra items left in the stack
  
    -- non-closable value
    local a, b = pcall(T.makeCfunc[[
      pushint 32
      toclose -1
    ]])
    assert(not a and string.find(b, "(C temporary)"))
  
  end
  
  
  --[[
  ** {==================================================================
  ** Testing memory limits
  ** ===================================================================
  --]]
  
  print("memory-allocation errors")
  
  checkerr("block too big", T.newuserdata, math.maxinteger)
  collectgarbage()
  local f = load"local a={}; for i=1,100000 do a[i]=i end"
  T.alloccount(10)
  checkerr(MEMERRMSG, f)
  T.alloccount()          -- remove limit
  
  
  -- test memory errors; increase limit for maximum memory by steps,
  -- o that we get memory errors in all allocations of a given
  -- task, until there is enough memory to complete the task without
  -- errors.
  function testbytes (s, f)
    collectgarbage()
    local M = T.totalmem()
    local oldM = M
    local a,b = nil
    while true do
      collectgarbage(); collectgarbage()
      T.totalmem(M)
      a, b = T.testC("pcall 0 1 0; pushstatus; return 2", f)
      T.totalmem(0)  -- remove limit
      if a and b == "OK" then break end       -- stop when no more errors
      if b ~= "OK" and b ~= MEMERRMSG then    -- not a memory error?
        error(a, 0)   -- propagate it
      end
      M = M + 7   -- increase memory limit
    end
    print(string.format("minimum memory for %s: %d bytes", s, M - oldM))
    return a
  end
  
  -- test memory errors; increase limit for number of allocations one
  -- by one, so that we get memory errors in all allocations of a given
  -- task, until there is enough allocations to complete the task without
  -- errors.
  
  function testalloc (s, f)
    collectgarbage()
    local M = 0
    local a,b = nil
    while true do
      collectgarbage(); collectgarbage()
      T.alloccount(M)
      a, b = T.testC("pcall 0 1 0; pushstatus; return 2", f)
      T.alloccount()  -- remove limit
      if a and b == "OK" then break end       -- stop when no more errors
      if b ~= "OK" and b ~= MEMERRMSG then    -- not a memory error?
        error(a, 0)   -- propagate it
      end
      M = M + 1   -- increase allocation limit
    end
    print(string.format("minimum allocations for %s: %d allocations", s, M))
    return a
  end
  
  
  local function testamem (s, f)
    testalloc(s, f)
    return testbytes(s, f)
  end
  
  
  -- doing nothing
  b = testamem("doing nothing", function () return 10 end)
  assert(b == 10)
  
  -- testing memory errors when creating a new state
  
  testamem("state creation", function ()
    local st = T.newstate()
    if st then T.closestate(st) end   -- close new state
    return st
  end)
  
  testamem("empty-table creation", function ()
    return {}
  end)
  
  testamem("string creation", function ()
    return "XXX" .. "YYY"
  end)
  
  testamem("coroutine creation", function()
             return coroutine.create(print)
  end)
  
  
  -- testing to-be-closed variables
  testamem("to-be-closed variables", function()
    local flag
    do
      local x <close> =
                setmetatable({}, {__close = function () flag = true end})
      flag = false
      local x = {}
    end
    return flag
  end)
  
  
  -- testing threads
  
  -- get main thread from registry (at index LUA_RIDX_MAINTHREAD == 1)
  mt = T.testC("rawgeti R 1; return 1")
  assert(type(mt) == "thread" and coroutine.running() == mt)
  
  
  
  function expand (n,s)
    if n==0 then return "" end
    local e = string.rep("=", n)
    return string.format("T.doonnewstack([%s[ %s;\n collectgarbage(); %s]%s])\n",
                                e, s, expand(n-1,s), e)
  end
  
  G=0; collectgarbage(); a =collectgarbage("count")
  load(expand(20,"G=G+1"))()
  assert(G==20); collectgarbage();  -- assert(gcinfo() <= a+1)
  
  testamem("running code on new thread", function ()
    return T.doonnewstack("x=1") == 0  -- try to create thread
  end)
  
  
  -- testing memory x compiler
  
  testamem("loadstring", function ()
    return load("x=1")  -- try to do load a string
  end)
  
  
  local testprog = [[
  local function foo () return end
  local t = {"x"}
  a = "aaa"
  for i = 1, #t do a=a..t[i] end
  return true
  ]]
  
  -- testing memory x dofile
  _G.a = nil
  local t =os.tmpname()
  local f = assert(io.open(t, "w"))
  f:write(testprog)
  f:close()
  testamem("dofile", function ()
    local a = loadfile(t)
    return a and a()
  end)
  assert(os.remove(t))
  assert(_G.a == "aaax")
  
  
  -- other generic tests
  
  testamem("gsub", function ()
    local a, b = string.gsub("alo alo", "(a)", function (x) return x..'b' end)
    return (a == 'ablo ablo')
  end)
  
  testamem("dump/undump", function ()
    local a = load(testprog)
    local b = a and string.dump(a)
    a = b and load(b)
    return a and a()
  end)
  
  local t = os.tmpname()
  testamem("file creation", function ()
    local f = assert(io.open(t, 'w'))
    assert (not io.open"nomenaoexistente")
    io.close(f);
    return not loadfile'nomenaoexistente'
  end)
  assert(os.remove(t))
  
  testamem("table creation", function ()
    local a, lim = {}, 10
    for i=1,lim do a[i] = i; a[i..'a'] = {} end
    return (type(a[lim..'a']) == 'table' and a[lim] == lim)
  end)
  
  testamem("constructors", function ()
    local a = {10, 20, 30, 40, 50; a=1, b=2, c=3, d=4, e=5}
    return (type(a) == 'table' and a.e == 5)
  end)
  
  local a = 1
  close = nil
  testamem("closure creation", function ()
    function close (b)
     return function (x) return b + x end
    end
    return (close(2)(4) == 6)
  end)
  
  testamem("using coroutines", function ()
    local a = coroutine.wrap(function ()
                coroutine.yield(string.rep("a", 10))
                return {}
              end)
    assert(string.len(a()) == 10)
    return a()
  end)
  
  do   -- auxiliary buffer
    local lim = 100
    local a = {}; for i = 1, lim do a[i] = "01234567890123456789" end
    testamem("auxiliary buffer", function ()
      return (#table.concat(a, ",") == 20*lim + lim - 1)
    end)
  end
  
  testamem("growing stack", function ()
    local function foo (n)
      if n == 0 then return 1 else return 1 + foo(n - 1) end
    end
    return foo(100)
  end)
  
  -- }==================================================================
  
  
  do   -- testing failing in 'lua_checkstack'
    local res = T.testC([[rawcheckstack 500000; return 1]])
    assert(res == false)
    local L = T.newstate()
    T.alloccount(0)   -- will be unable to reallocate the stack
    res = T.testC(L, [[rawcheckstack 5000; return 1]])
    T.alloccount()
    T.closestate(L)
    assert(res == false)
  end
  
  do   -- closing state with no extra memory
    local L = T.newstate()
    T.alloccount(0)
    T.closestate(L)
    T.alloccount()
  end
  
  do   -- garbage collection with no extra memory
    local L = T.newstate()
    T.loadlib(L)
    local res = (T.doremote(L, [[
      _ENV = require"_G"
      local T = require"T"
      local a = {}
      for i = 1, 1000 do a[i] = 'i' .. i end    -- grow string table
      local stsize, stuse = T.querystr()
      assert(stuse > 1000)
      local function foo (n)
        if n > 0 then foo(n - 1) end
      end
      foo(180)    -- grow stack
      local _, stksize = T.stacklevel()
      assert(stksize > 180)
      a = nil
      T.alloccount(0)
      collectgarbage()
      T.alloccount()
      -- stack and string table could not be reallocated,
      -- so they kept their sizes (without errors)
      assert(select(2, T.stacklevel()) == stksize)
      assert(T.querystr() == stsize)
      return 'ok'
    ]]))
    assert(res == 'ok')
    T.closestate(L)
  end
  
  print'+'
  
  -- testing some auxlib functions
  local function gsub (a, b, c)
    a, b = T.testC("gsub 2 3 4; gettop; return 2", a, b, c)
    assert(b == 5)
    return a
  end
  
  assert(gsub("alo.alo.uhuh.", ".", "//") == "alo//alo//uhuh//")
  assert(gsub("alo.alo.uhuh.", "alo", "//") == "//.//.uhuh.")
  assert(gsub("", "alo", "//") == "")
  assert(gsub("...", ".", "/.") == "/././.")
  assert(gsub("...", "...", "") == "")
  
  
  -- testing luaL_newmetatable
  local mt_xuxu, res, top = T.testC("newmetatable xuxu; gettop; return 3")
  assert(type(mt_xuxu) == "table" and res and top == 3)
  local d, res, top = T.testC("newmetatable xuxu; gettop; return 3")
  assert(mt_xuxu == d and not res and top == 3)
  d, res, top = T.testC("newmetatable xuxu1; gettop; return 3")
  assert(mt_xuxu ~= d and res and top == 3)
  
  x = T.newuserdata(0);
  y = T.newuserdata(0);
  T.testC("pushstring xuxu; gettable R; setmetatable 2", x)
  assert(getmetatable(x) == mt_xuxu)
  
  -- testing luaL_testudata
  -- correct metatable
  local res1, res2, top = T.testC([[testudata -1 xuxu
                        testudata 2 xuxu
                    gettop
                    return 3]], x)
  assert(res1 and res2 and top == 4)
  
  -- wrong metatable
  res1, res2, top = T.testC([[testudata -1 xuxu1
                  testudata 2 xuxu1
                  gettop
                  return 3]], x)
  assert(not res1 and not res2 and top == 4)
  
  -- non-existent type
  res1, res2, top = T.testC([[testudata -1 xuxu2
                  testudata 2 xuxu2
                  gettop
                  return 3]], x)
  assert(not res1 and not res2 and top == 4)
  
  -- userdata has no metatable
  res1, res2, top = T.testC([[testudata -1 xuxu
                  testudata 2 xuxu
                  gettop
                  return 3]], y)
  assert(not res1 and not res2 and top == 4)
  
  -- erase metatables
  do
    local r = debug.getregistry()
    assert(r.xuxu == mt_xuxu and r.xuxu1 == d)
    r.xuxu = nil; r.xuxu1 = nil
  end
  
  print'OK'
  
  