Avoid excessive name pollution in test files

Test files are more polite regarding the use of globals when locals
would do, and when globals are necessary deleting them after use.

testes/coroutine.lua

@@ -30,7 +30,8 @@ local function eqtab (t1, t2)
 end
 
 _G.x = nil   -- declare x
-function foo (a, ...)
+_G.f = nil   -- declare f
+local function foo (a, ...)
   local x, y = coroutine.running()
   assert(x == f and y == false)
   -- next call should not corrupt coroutine (but must fail,
@@ -67,10 +68,11 @@ assert(coroutine.status(f) == "dead")
 s, a = coroutine.resume(f, "xuxu")
 assert(not s and string.find(a, "dead") and coroutine.status(f) == "dead")
 
+_G.f = nil
 
 -- yields in tail calls
 local function foo (i) return coroutine.yield(i) end
-f = coroutine.wrap(function ()
+local f = coroutine.wrap(function ()
   for i=1,10 do
     assert(foo(i) == _G.x)
   end
@@ -79,8 +81,10 @@ end)
 for i=1,10 do _G.x = i; assert(f(i) == i) end
 _G.x = 'xuxu'; assert(f('xuxu') == 'a')
 
+_G.x = nil
+
 -- recursive
-function pf (n, i)
+local function pf (n, i)
   coroutine.yield(n)
   pf(n*i, i+1)
 end
@@ -93,14 +97,14 @@ for i=1,10 do
 end
 
 -- sieve
-function gen (n)
+local function gen (n)
   return coroutine.wrap(function ()
     for i=2,n do coroutine.yield(i) end
   end)
 end
 
 
-function filter (p, g)
+local function filter (p, g)
   return coroutine.wrap(function ()
     while 1 do
       local n = g()
@@ -221,14 +225,14 @@ do
   -- <close> versus pcall in coroutines
   local X = false
   local Y = false
-  function foo ()
+  local function foo ()
     local x <close> = func2close(function (self, err)
       Y = debug.getinfo(2)
       X = err
     end)
     error(43)
   end
-  co = coroutine.create(function () return pcall(foo) end)
+  local co = coroutine.create(function () return pcall(foo) end)
   local st1, st2, err = coroutine.resume(co)
   assert(st1 and not st2 and err == 43)
   assert(X == 43 and Y.what == "C")
@@ -275,7 +279,7 @@ end
 
 -- yielding across C boundaries
 
-co = coroutine.wrap(function()
+local co = coroutine.wrap(function()
        assert(not pcall(table.sort,{1,2,3}, coroutine.yield))
        assert(coroutine.isyieldable())
        coroutine.yield(20)
@@ -303,15 +307,15 @@ local r1, r2, v = f1(nil)
 assert(r1 and not r2 and v[1] ==  (10 + 1)*10/2)
 
 
-function f (a, b) a = coroutine.yield(a);  error{a + b} end
-function g(x) return x[1]*2 end
+local function f (a, b) a = coroutine.yield(a);  error{a + b} end
+local function g(x) return x[1]*2 end
 
 co = coroutine.wrap(function ()
        coroutine.yield(xpcall(f, g, 10, 20))
      end)
 
 assert(co() == 10)
-r, msg = co(100)
+local r, msg = co(100)
 assert(not r and msg == 240)
 
 
@@ -373,9 +377,10 @@ assert(not a and b == foo and coroutine.status(x) == "dead")
 a,b = coroutine.resume(x)
 assert(not a and string.find(b, "dead") and coroutine.status(x) == "dead")
 
+goo = nil
 
 -- co-routines x for loop
-function all (a, n, k)
+local function all (a, n, k)
   if k == 0 then coroutine.yield(a)
   else
     for i=1,n do
@@ -415,7 +420,7 @@ assert(f() == 43 and f() == 53)
 
 -- old bug: attempt to resume itself
 
-function co_func (current_co)
+local function co_func (current_co)
   assert(coroutine.running() == current_co)
   assert(coroutine.resume(current_co) == false)
   coroutine.yield(10, 20)
@@ -491,15 +496,16 @@ a = nil
 -- access to locals of erroneous coroutines
 local x = coroutine.create (function ()
             local a = 10
-            _G.f = function () a=a+1; return a end
+            _G.F = function () a=a+1; return a end
             error('x')
           end)
 
 assert(not coroutine.resume(x))
 -- overwrite previous position of local `a'
 assert(not coroutine.resume(x, 1, 1, 1, 1, 1, 1, 1))
-assert(_G.f() == 11)
-assert(_G.f() == 12)
+assert(_G.F() == 11)
+assert(_G.F() == 12)
+_G.F = nil
 
 
 if not T then
@@ -510,7 +516,7 @@ else
 
   local turn
   
-  function fact (t, x)
+  local function fact (t, x)
     assert(turn == t)
     if x == 0 then return 1
     else return x*fact(t, x-1)
@@ -579,6 +585,7 @@ else
   _G.X = nil; co(); assert(_G.X == line + 2 and _G.XX == nil)
   _G.X = nil; co(); assert(_G.X == line + 3 and _G.XX == 20)
   assert(co() == 10)
+  _G.X = nil
 
   -- testing yields in count hook
   co = coroutine.wrap(function ()
@@ -656,6 +663,8 @@ else
 
   assert(X == 'a a a' and Y == 'OK')
 
+  X, Y = nil
+
 
   -- resuming running coroutine
   C = coroutine.create(function ()
@@ -701,7 +710,7 @@ else
     X = function (x) coroutine.yield(x, 'BB'); return 'CC' end;
     return 'ok']]))
 
-  t = table.pack(T.testC(state, [[
+  local t = table.pack(T.testC(state, [[
     rawgeti R 1     # get main thread
     pushstring 'XX'
     getglobal X    # get function for body
@@ -730,13 +739,13 @@ end
 
 
 -- leaving a pending coroutine open
-_X = coroutine.wrap(function ()
+_G.TO_SURVIVE = coroutine.wrap(function ()
       local a = 10
       local x = function () a = a+1 end
       coroutine.yield()
     end)
 
-_X()
+_G.TO_SURVIVE()
 
 
 if not _soft then
@@ -935,7 +944,7 @@ assert(run(function ()
 do local _ENV = _ENV
   f = function () AAA = BBB + 1; return AAA end
 end
-g = new(10); g.k.BBB = 10;
+local g = new(10); g.k.BBB = 10;
 debug.setupvalue(f, 1, g)
 assert(run(f, {"idx", "nidx", "idx"}) == 11)
 assert(g.k.AAA == 11)
@@ -1075,6 +1084,8 @@ assert(#a == 3 and a[1] == a[2] and a[2] == a[3] and a[3] == 34)
 
 -- testing yields with continuations
 
+local y
+
 co = coroutine.wrap(function (...) return
        T.testC([[ # initial function
           yieldk 1 2
@@ -1127,6 +1138,9 @@ assert(x == "YIELD" and y == 4)
 
 assert(not pcall(co))   -- coroutine should be dead
 
+_G.ctx = nil
+_G.status = nil
+
 
 -- bug in nCcalls
 local co = coroutine.wrap(function ()