lua: vendor PUC-Rio 5.1 test suite (22 .lua files)

lib/lua/lua-tests/api.lua

@@ -0,0 +1,711 @@
+
+if T==nil then
+  (Message or print)('\a\n >>> testC not active: skipping API tests <<<\n\a')
+  return
+end
+
+
+
+function tcheck (t1, t2)
+  table.remove(t1, 1)  -- remove code
+  assert(table.getn(t1) == table.getn(t2))
+  for i=1,table.getn(t1) do assert(t1[i] == t2[i]) end
+end
+
+function pack(...) return arg end
+
+
+print('testing C API')
+
+-- testing allignment
+a = T.d2s(12458954321123)
+assert(string.len(a) == 8)   -- sizeof(double)
+assert(T.s2d(a) == 12458954321123)
+
+a,b,c = T.testC("pushnum 1; pushnum 2; pushnum 3; return 2")
+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==0 and b==1 and c==0)
+
+
+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; gettop; 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; gettop; return .", 2, 3, 4))
+tcheck(t, {n=2,2,4})
+
+t = pack(T.testC("insert -1; gettop; return .", 2, 3))
+tcheck(t, {n=2,2,3})
+
+t = pack(T.testC("insert 3; gettop; return .", 2, 3, 4, 5))
+tcheck(t, {n=4,2,5,3,4})
+
+t = pack(T.testC("replace 2; gettop; return .", 2, 3, 4, 5))
+tcheck(t, {n=3,5,3,4})
+
+t = pack(T.testC("replace -2; gettop; return .", 2, 3, 4, 5))
+tcheck(t, {n=3,2,3,5})
+
+t = pack(T.testC("remove 3; gettop; return .", 2, 3, 4, 5))
+tcheck(t, {n=3,2,4,5})
+
+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; gettop; 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; gettop; return .", "alo", 2, 3, "joao", 12))
+tcheck(t, {n=1,"alo23joao12"})
+
+-- testing MULTRET
+t = pack(T.testC("rawcall 2,-1; gettop; 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([[call 1 -1; pop 1; tostring -1; return 1]], unpack, a)
+  assert(b == "10")
+end
+
+
+-- testing lessthan
+assert(T.testC("lessthan 2 5, return 1", 3, 2, 2, 4, 2, 2))
+assert(T.testC("lessthan 5 2, return 1", 4, 2, 2, 3, 2, 2))
+assert(not T.testC("lessthan 2 -3, return 1", "4", "2", "2", "3", "2", "2"))
+assert(not T.testC("lessthan -3 2, return 1", "3", "2", "2", "4", "2", "2"))
+
+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("lessthan 2 5, return 1", a3, 2, 2, a4, 2, 2))
+assert(T.testC("lessthan 5 -6, return 1", a4, 2, 2, a3, 2, 2))
+a,b = T.testC("lessthan 5 -6, return 2", a1, 2, 2, a3, 2, 20)
+assert(a == 20 and b == false)
+
+
+-- testing lua_is
+
+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 a+b+c+d+e+f+g+(100*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
+
+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", "alo\0\0a") == 6)
+assert(to("objsize", T.newuserdata(0)) == 0)
+assert(to("objsize", T.newuserdata(101)) == 101)
+assert(to("objsize", 12) == 2)
+assert(to("objsize", 12, 3) == 0)
+assert(to("tonumber", {}) == 0)
+assert(to("tonumber", "12") == 12)
+assert(to("tonumber", "s2") == 0)
+assert(to("tonumber", 1, 20) == 0)
+a = to("tocfunction", math.deg)
+assert(a(3) == math.deg(3) and a ~= math.deg)
+
+
+-- testing errors
+
+a = T.testC([[
+  loadstring 2; call 0,1;
+  pushvalue 3; insert -2; call 1, 1;
+  call 0, 0;
+  return 1
+]], "x=150", function (a) assert(a==nil); return 3 end)
+
+assert(type(a) == 'string' and x == 150)
+
+function check3(p, ...)
+  assert(arg.n == 3)
+  assert(string.find(arg[3], p))
+end
+check3(":1:", T.testC("loadstring 2; gettop; return .", "x="))
+check3("cannot read", T.testC("loadfile 2; gettop; return .", "."))
+check3("cannot open xxxx", T.testC("loadfile 2; gettop; return .", "xxxx"))
+
+-- testing table access
+
+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)
+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)
+
+-- testing next
+a = {}
+t = pack(T.testC("next; gettop; return .", a, nil))
+tcheck(t, {n=1,a})
+a = {a=3}
+t = pack(T.testC("next; gettop; return .", a, nil))
+tcheck(t, {n=3,a,'a',3})
+t = pack(T.testC("next; pop 1; next; gettop; 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
+
+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")
+
+
+-- testing environments
+
+assert(T.testC"pushvalue G; return 1" == _G)
+assert(T.testC"pushvalue E; return 1" == _G)
+local a = {}
+T.testC("replace E; return 1", a)
+assert(T.testC"pushvalue G; return 1" == _G)
+assert(T.testC"pushvalue E; return 1" == a)
+assert(debug.getfenv(T.testC) == a)
+assert(debug.getfenv(T.upvalue) == _G)
+-- userdata inherit environment
+local u = T.testC"newuserdata 0; return 1"
+assert(debug.getfenv(u) == a)
+-- functions inherit environment
+u = T.testC"pushcclosure 0; return 1"
+assert(debug.getfenv(u) == a)
+debug.setfenv(T.testC, _G)
+assert(T.testC"pushvalue E; return 1" == _G)
+
+local b = newproxy()
+assert(debug.getfenv(b) == _G)
+assert(debug.setfenv(b, a))
+assert(debug.getfenv(b) == a)
+
+
+
+-- 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 n = T.testC("gettable R; return 1", "n")
+  print("n", n)
+  for i=0,n do
+    print(i, T.testC("gettable R; return 1", 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)   -- cria lixo
+  d = nil
+  assert(debug.getmetatable(x).__gc == F)
+  loadstring("table.insert({}, {})")()   -- cria mais lixo
+  collectgarbage()   -- forca coleta de lixo durante coleta!
+  assert(debug.getmetatable(x).__gc == F)   -- coleta anterior nao melou isso?
+  local dummy = {}    -- cria lixo durante coleta
+  if A ~= nil then
+    assert(type(A) == "userdata")
+    assert(T.udataval(A) == B)
+    debug.getmetatable(A)    -- just acess 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 newproxy(false) end
+  assert(collectgarbage("count") > x+10)
+  collectgarbage()
+  assert(collectgarbage("count") <= x+1)
+  -- udata with finalizer
+  x = collectgarbage("count")
+  collectgarbage()
+  collectgarbage("stop")
+  a = newproxy(true)
+  getmetatable(a).__gc = function () end
+  for i=1,1000 do newproxy(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)
+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)
+
+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(table.getn(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(table.getn(cl) == 4)
+-- check order of collection
+assert(cl[2] == n5 and cl[3] == nb and cl[4] == na)
+
+
+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(table.getn(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(table.getn(cl) == 0)
+for n in pairs(a) do a[n] = nil end
+collectgarbage()
+assert(table.getn(cl) == 1 and cl[1] == x)   -- old `x' must be collected
+
+-- testing lua_equal
+assert(T.testC("equal 2 4; return 1", print, 1, print, 20))
+assert(T.testC("equal 3 2; return 1", 'alo', "alo"))
+assert(T.testC("equal 2 3; return 1", nil, nil))
+assert(not T.testC("equal 2 3; return 1", {}, {}))
+assert(not T.testC("equal 2 3; return 1"))
+assert(not T.testC("equal 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("equal 2 3; return 1", f(10), f(10)))
+  assert(not T.testC("equal 2 3; return 1", f(10), f(20)))
+  t.__eq = nil
+  assert(f(10) ~= f(10))
+end
+
+print'+'
+
+
+
+-------------------------------------------------------------------------
+do   -- testing errors during GC
+  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 error during GC
+    debug.setmetatable(a[i], {__gc = function (x) error("error inside 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) loadstring("A=A+1")() end})
+  end
+  _G.A = 0
+  a = 0
+  while 1 do
+  if xpcall(collectgarbage, function (s) a=a+1 end) then
+    break   -- stop if no more errors
+  end
+  end
+  assert(a == 10)  -- number of errors
+  assert(A == 10)  -- number of normal collections
+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(pack(T.doremote(L1, "function f () return 'alo', 3 end; f()")).n == 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 b == 3 and type(c) == "string")   -- 3 == syntax error
+
+T.loadlib(L1)
+a, b = T.doremote(L1, [[
+  a = strlibopen()
+  a = packageopen()
+  a = baselibopen(); assert(a == _G and require("_G") == a)
+  a = iolibopen(); assert(type(a.read) == "function")
+  assert(require("io") == a)
+  a = tablibopen(); assert(type(a.insert) == "function")
+  a = dblibopen(); assert(type(a.getlocal) == "function")
+  a = mathlibopen(); 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, [[pushstring a; gettable G; pushstring x; pushnum 1;
+             settable -3]])
+assert(T.doremote(L1, "return a.x") == "1")
+
+T.closestate(L1)
+
+L1 = nil
+
+print('+')
+
+-------------------------------------------------------------------------
+-- testing memory limits
+-------------------------------------------------------------------------
+collectgarbage()
+T.totalmem(T.totalmem()+5000)   -- set low memory limit (+5k)
+assert(not pcall(loadstring"local a={}; for i=1,100000 do a[i]=i end"))
+T.totalmem(1000000000)          -- restore high limit
+
+
+local function stack(x) if x>0 then stack(x-1) end end
+
+-- test memory errors; increase memory limit in small steps, so that
+-- we get memory errors in different parts of a given task, up to there
+-- is enough memory to complete the task without errors
+function testamem (s, f)
+  collectgarbage()
+  stack(10)    -- ensure minimum stack size
+  local M = T.totalmem()
+  local oldM = M
+  local a,b = nil
+  while 1 do
+    M = M+3   -- increase memory limit in small steps
+    T.totalmem(M)
+    a, b = pcall(f)
+    if a and b then break end       -- stop when no more errors
+    collectgarbage()
+    if not a and not string.find(b, "memory") then   -- `real' error?
+      T.totalmem(1000000000)  -- restore high limit
+      error(b, 0)
+    end
+  end
+  T.totalmem(1000000000)  -- restore high limit
+  print("\nlimit for " .. s .. ": " .. M-oldM)
+  return b
+end
+
+
+-- testing memory errors when creating a new state
+
+b = testamem("state creation", T.newstate)
+T.closestate(b);  -- close new state
+
+
+-- testing threads
+
+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")
+loadstring(expand(20,"G=G+1"))()
+assert(G==20); collectgarbage();  -- assert(gcinfo() <= a+1)
+
+testamem("thread creation", function ()
+  return T.doonnewstack("x=1") == 0  -- try to create thread
+end)
+
+
+-- testing memory x compiler
+
+testamem("loadstring", function ()
+  return loadstring("x=1")  -- try to do a loadstring
+end)
+
+
+local testprog = [[
+local function foo () return end
+local t = {"x"}
+a = "aaa"
+for _, v in ipairs(t) do a=a..v 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("string creation", 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 = loadstring(testprog)
+  local b = a and string.dump(a)
+  a = b and loadstring(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)
+
+local a = 1
+close = nil
+testamem("closure creation", function ()
+  function close (b,c)
+   return function (x) return a+b+c+x end
+  end
+  return (close(2,3)(4) == 10)
+end)
+
+testamem("coroutines", function ()
+  local a = coroutine.wrap(function ()
+              coroutine.yield(string.rep("a", 10))
+              return {}
+            end)
+  assert(string.len(a()) == 10)
+  return a()
+end)
+
+print'+'
+
+-- testing some auxlib functions
+assert(T.gsub("alo.alo.uhuh.", ".", "//") == "alo//alo//uhuh//")
+assert(T.gsub("alo.alo.uhuh.", "alo", "//") == "//.//.uhuh.")
+assert(T.gsub("", "alo", "//") == "")
+assert(T.gsub("...", ".", "/.") == "/././.")
+assert(T.gsub("...", "...", "") == "")
+
+
+print'OK'
+