[Tarantool-patches] [PATCH luajit 2/3] test: adapt PUC-Rio Lua 5.1 test suite for LuaJIT

[Sergey Kaplun via Tarantool-patches <tarantool-patches@dev.tarantool.org>]

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In some insignificant details LuaJIT's behaviour is not the same
as the behaviour of Lua 5.1.

Tests in the following files are disabled with corresponding comments:
* closure.lua
* constructs.lua
* db.lua
* errors.lua
* literals.lua
* main.lua
* math.lua
* nextvar.lua
* pm.lua
* strings.lua
* vararg.lua

See full list of disabled tests to adapt in
https://github.com/tarantool/tarantool/issues/5870.

jit.off() as prologue and jit.on() as epilogue is added to one test
chunk in gc.lua for stable (JIT unrelated) GC test results.

Part of tarantool/tarantool#5845
Part of tarantool/tarantool#4473
---
 test/PUC-Lua-5.1-tests/closure.lua    | 12 ++++-
 test/PUC-Lua-5.1-tests/constructs.lua |  7 +++
 test/PUC-Lua-5.1-tests/db.lua         | 75 ++++++++++++++++++++-------
 test/PUC-Lua-5.1-tests/errors.lua     | 28 +++++++---
 test/PUC-Lua-5.1-tests/gc.lua         |  5 ++
 test/PUC-Lua-5.1-tests/literals.lua   |  5 ++
 test/PUC-Lua-5.1-tests/main.lua       | 56 ++++++++++++++------
 test/PUC-Lua-5.1-tests/math.lua       |  7 ++-
 test/PUC-Lua-5.1-tests/nextvar.lua    |  7 +++
 test/PUC-Lua-5.1-tests/pm.lua         |  6 ++-
 test/PUC-Lua-5.1-tests/strings.lua    | 17 +++++-
 test/PUC-Lua-5.1-tests/vararg.lua     | 20 ++++---
 12 files changed, 195 insertions(+), 50 deletions(-)

diff --git a/test/PUC-Lua-5.1-tests/closure.lua b/test/PUC-Lua-5.1-tests/closure.lua
index 27ca0ad..e9bd564 100644
--- a/test/PUC-Lua-5.1-tests/closure.lua
+++ b/test/PUC-Lua-5.1-tests/closure.lua
@@ -174,7 +174,10 @@ f = coroutine.wrap(foo)
 local a = {}
 assert(f(a) == _G)
 local a,b = pcall(f)
-assert(a and b == _G)
+-- LuaJIT getfenv() behaviour is different in tail calls.
+-- See also https://github.com/tarantool/tarantool/issues/5713.
+-- Test is disabled for LuaJIT for now.
+-- assert(a and b == _G)
 
 
 -- tests for multiple yield/resume arguments
@@ -261,6 +264,12 @@ end
 
 local x = gen(100)
 local a = {}
+-- In Lua 5.1 math.mod() is renamed to math.fmod() if build
+-- Lua 5.1 without flag `-DLUA_COMPAT_MOD`.
+-- LuaJIT also has math.fmod() instead math.mod() builtin.
+-- See also https://github.com/tarantool/tarantool/issues/5711.
+-- Test is disabled.
+--[=[
 while 1 do
   local n = x()
   if n == nil then break end
@@ -269,6 +278,7 @@ while 1 do
 end
 
 assert(table.getn(a) == 25 and a[table.getn(a)] == 97)
+--]=]
 
 
 -- errors in coroutines
diff --git a/test/PUC-Lua-5.1-tests/constructs.lua b/test/PUC-Lua-5.1-tests/constructs.lua
index 5fb3798..6776ee6 100644
--- a/test/PUC-Lua-5.1-tests/constructs.lua
+++ b/test/PUC-Lua-5.1-tests/constructs.lua
@@ -200,6 +200,12 @@ a,b = F(nil)==nil; assert(a == true and b == nil)
 
 function ID(x) return x end
 
+-- In Lua 5.1 math.mod() is renamed to math.fmod() if build
+-- Lua 5.1 without flag `-DLUA_COMPAT_MOD`.
+-- LuaJIT also has math.fmod() instead math.mod() builtin.
+-- See also https://github.com/tarantool/tarantool/issues/5711.
+-- Test is disabled.
+--[=[
 function f(t, i)
   local b = t.n
   local res = math.mod(math.floor(i/c), b)+1
@@ -236,5 +242,6 @@ repeat
   if math.mod(i,4000) == 0 then print('+') end
   i = i+1
 until i==c
+--]=]
 
 print'OK'
diff --git a/test/PUC-Lua-5.1-tests/db.lua b/test/PUC-Lua-5.1-tests/db.lua
index 9d2c86f..591a006 100644
--- a/test/PUC-Lua-5.1-tests/db.lua
+++ b/test/PUC-Lua-5.1-tests/db.lua
@@ -95,6 +95,10 @@ repeat
   assert(g(f) == 'a')
 until 1
 
+-- LuaJIT interprets a return from calling result of loadstring()
+-- with a new line number unlike Lua does.
+-- See also https://github.com/tarantool/tarantool/issues/5693.
+--[=[
 test([[if
 math.sin(1)
 then
@@ -149,7 +153,7 @@ end
 ]], {1,2,1,2,1,3})
 
 test([[for i=1,4 do a=1 end]], {1,1,1,1,1})
-
+--]=]
 
 
 print'+'
@@ -178,8 +182,13 @@ function f(a,b)
   local _, x = debug.getlocal(1, 1)
   local _, y = debug.getlocal(1, 2)
   assert(x == a and y == b)
-  assert(debug.setlocal(2, 3, "pera") == "AA".."AA")
-  assert(debug.setlocal(2, 4, "maçã") == "B")
+  -- f() function is called only from g(...) vararg function.
+  -- Lua 5.1 interprets ... in the vararg functions like additional
+  -- first argument unlike LuaJIT does.
+  -- This extension is from Lua 5.2.
+  -- See also https://github.com/tarantool/tarantool/issues/5694.
+  -- assert(debug.setlocal(2, 3, "pera") == "AA".."AA")
+  -- assert(debug.setlocal(2, 4, "maçã") == "B")
   x = debug.getinfo(2)
   assert(x.func == g and x.what == "Lua" and x.name == 'g' and
          x.nups == 0 and string.find(x.source, "^@.*db%.lua"))
@@ -208,11 +217,13 @@ function g(...)
   local feijao
   local AAAA,B = "xuxu", "mamão"
   f(AAAA,B)
-  assert(AAAA == "pera" and B == "maçã")
+  -- Test is disabled for LuaJIT for now. See comment in f().
+  -- assert(AAAA == "pera" and B == "maçã")
   do
      local B = 13
      local x,y = debug.getlocal(1,5)
-     assert(x == 'B' and y == 13)
+     -- Test is disabled for LuaJIT for now. See comment in f().
+     -- assert(x == 'B' and y == 13)
   end
 end
 
@@ -276,7 +287,8 @@ debug.sethook(function (e)
 end, "c")
 
 a:f(1,2,3,4,5)
-assert(X.self == a and X.a == 1   and X.b == 2 and X.arg.n == 3 and X.c == nil)
+-- Test is disabled for LuaJIT for now. See comment in f().
+-- assert(X.self == a and X.a == 1   and X.b == 2 and X.arg.n == 3 and X.c == nil)
 assert(XX == 12)
 assert(debug.gethook() == nil)
 
@@ -314,12 +326,20 @@ assert(debug.setupvalue(io.read, 1, 10) == nil)
 
 -- testing count hooks
 local a=0
+-- LuaJIT does not check hooks at traces without defined
+-- -DLUAJIT_ENABLE_CHECKHOOK.
+-- For more information see <src/lj_record.c> or commit
+-- 6bce6b118eeb2bb7f36157de158e5cccf0ea68e5 (Add compile-time
+-- option LUAJIT_ENABLE_CHECKHOOK. Disabled by default.).
+-- See also https://github.com/tarantool/tarantool/issues/5701.
+--[[
 debug.sethook(function (e) a=a+1 end, "", 1)
 a=0; for i=1,1000 do end; assert(1000 < a and a < 1012)
 debug.sethook(function (e) a=a+1 end, "", 4)
 a=0; for i=1,1000 do end; assert(250 < a and a < 255)
 local f,m,c = debug.gethook()
 assert(m == "" and c == 4)
+--]]
 debug.sethook(function (e) a=a+1 end, "", 4000)
 a=0; for i=1,1000 do end; assert(a == 0)
 debug.sethook(print, "", 2^24 - 1)   -- count upperbound
@@ -352,18 +372,24 @@ function g1(x) g(x) end
 
 local function h (x) local f=g1; return f(x) end
 
-h(true)
+-- LuaJIT does not provide information about tail calls,
+-- unlike Lua does. getfenv() behaviour is also different here.
+-- Test is disabled for LuaJIT for now.
+-- See also https://github.com/tarantool/tarantool/issues/5702.
+-- h(true)
 
 local b = {}
-debug.sethook(function (e) table.insert(b, e) end, "cr")
-h(false)
-debug.sethook()
+-- Behavior is different for LuaJIT. See the comment above.
+-- debug.sethook(function (e) table.insert(b, e) end, "cr")
+-- h(false)
+-- debug.sethook()
 local res = {"return",   -- first return (from sethook)
   "call", "call", "call", "call",
   "return", "tail return", "return", "tail return",
   "call",    -- last call (to sethook)
 }
-for _, k in ipairs(res) do assert(k == table.remove(b, 1)) end
+-- Behavior is different for LuaJIT. See the comment above.
+-- for _, k in ipairs(res) do assert(k == table.remove(b, 1)) end
 
 
 lim = 30000
@@ -375,7 +401,8 @@ local function foo (x)
   end
 end
 
-foo(lim)
+-- Behavior is different for LuaJIT. See the comment above.
+-- foo(lim)
 
 
 print"+"
@@ -411,7 +438,11 @@ end
 
 local co = coroutine.create(f)
 coroutine.resume(co, 3)
-checktraceback(co, {"yield", "db.lua", "tail", "tail", "tail"})
+-- LuaJIT does not provide information about tail calls,
+-- unlike Lua does.
+-- See also https://github.com/tarantool/tarantool/issues/5703.
+-- Test is disabled for LuaJIT for now.
+-- checktraceback(co, {"yield", "db.lua", "tail", "tail", "tail"})
 
 
 co = coroutine.create(function (x)
@@ -429,8 +460,12 @@ local _, l = coroutine.resume(co, 10)
 local x = debug.getinfo(co, 1, "lfLS")
 assert(x.currentline == l.currentline and x.activelines[x.currentline])
 assert(type(x.func) == "function")
+-- LuaJIT does not report line with single "end" statement as
+-- an active line in debug.getinfo(), unlike Lua does.
+-- See also https://github.com/tarantool/tarantool/issues/5708.
+-- Test is disabled for LuaJIT for now.
 for i=x.linedefined + 1, x.lastlinedefined do
-  assert(x.activelines[i])
+  -- assert(x.activelines[i])
   x.activelines[i] = nil
 end
 assert(next(x.activelines) == nil)   -- no 'extra' elements
@@ -441,8 +476,10 @@ a,b = debug.getlocal(co, 1, 2)
 assert(a == "a" and b == 1)
 debug.setlocal(co, 1, 2, "hi")
 assert(debug.gethook(co) == foo)
-assert(table.getn(tr) == 2 and
-       tr[1] == l.currentline-1 and tr[2] == l.currentline)
+-- LuaJIT does not support per-coroutine hooks.
+-- Test is disabled for LuaJIT.
+-- assert(table.getn(tr) == 2 and
+--        tr[1] == l.currentline-1 and tr[2] == l.currentline)
 
 a,b,c = pcall(coroutine.resume, co)
 assert(a and b and c == l.currentline+1)
@@ -450,9 +487,11 @@ checktraceback(co, {"yield", "in function <"})
 
 a,b = coroutine.resume(co)
 assert(a and b == "hi")
-assert(table.getn(tr) == 4 and tr[4] == l.currentline+2)
+-- Behavior is different for LuaJIT. See the comment above.
+-- assert(table.getn(tr) == 4 and tr[4] == l.currentline+2)
 assert(debug.gethook(co) == foo)
-assert(debug.gethook() == nil)
+-- Behavior is different for LuaJIT. See the comment above.
+-- assert(debug.gethook() == nil)
 checktraceback(co, {})
 
 
diff --git a/test/PUC-Lua-5.1-tests/errors.lua b/test/PUC-Lua-5.1-tests/errors.lua
index e881211..3270033 100644
--- a/test/PUC-Lua-5.1-tests/errors.lua
+++ b/test/PUC-Lua-5.1-tests/errors.lua
@@ -72,8 +72,12 @@ checkmessage("b=1; local aaa='a'; x=aaa+b", "local 'aaa'")
 checkmessage("aaa={}; x=3/aaa", "global 'aaa'")
 checkmessage("aaa='2'; b=nil;x=aaa*b", "global 'b'")
 checkmessage("aaa={}; x=-aaa", "global 'aaa'")
-assert(not string.find(doit"aaa={}; x=(aaa or aaa)+(aaa and aaa)", "'aaa'"))
-assert(not string.find(doit"aaa={}; (aaa or aaa)()", "'aaa'"))
+-- LuaJIT reports the error as the following here:
+-- "attempt to perform arithmetic on global 'aaa' (a table value)"
+-- Lua 5.1 doesn't report variable name here.
+-- Test is disabled for LuaJIT.
+-- assert(not string.find(doit"aaa={}; x=(aaa or aaa)+(aaa and aaa)", "'aaa'"))
+-- assert(not string.find(doit"aaa={}; (aaa or aaa)()", "'aaa'"))
 
 checkmessage([[aaa=9
 repeat until 3==3
@@ -100,9 +104,12 @@ while 1 do
   insert(prefix, a)
 end]], "global 'insert'")
 
-checkmessage([[  -- tail call
-  return math.sin("a")
-]], "'sin'")
+-- Implementation of fast functions in LuaJIT does not provide
+-- enough info on failure.
+-- Test is disabled for LuaJIT.
+-- checkmessage([[  -- tail call
+--   return math.sin("a")
+-- ]], "'sin'")
 
 checkmessage([[collectgarbage("nooption")]], "invalid option")
 
@@ -193,7 +200,11 @@ checksyntax("[[a]]", "", "[[a]]", 1)
 checksyntax("'aa'", "", "'aa'", 1)
 
 -- test 255 as first char in a chunk
-checksyntax("\255a = 1", "", "\255", 1)
+-- LuaJIT does not avoid to use non-alphabetic symbols
+-- as identifiers, unlike Lua does.
+-- For more details see <src/lj_char.c> and <src/lj_lex.c>.
+-- Test is disabled for LuaJIT.
+-- checksyntax("\255a = 1", "", "\255", 1)
 
 doit('I = loadstring("a=9+"); a=3')
 assert(a==3 and I == nil)
@@ -215,7 +226,10 @@ local function testrep (init, rep)
 end
 testrep("a=", "{")
 testrep("a=", "(")
-testrep("", "a(")
+-- When compiled with LUAJIT_ENABLE_GC64 LJ_MAX_SLOTS limit
+-- is reached and error is LJ_ERR_XSLOTS ("function or expression too
+-- complex"). Test is disabled for LuaJIT.
+-- testrep("", "a(")
 testrep("", "do ")
 testrep("", "while a do ")
 testrep("", "if a then else ")
diff --git a/test/PUC-Lua-5.1-tests/gc.lua b/test/PUC-Lua-5.1-tests/gc.lua
index 86a9f75..b767104 100644
--- a/test/PUC-Lua-5.1-tests/gc.lua
+++ b/test/PUC-Lua-5.1-tests/gc.lua
@@ -108,11 +108,16 @@ local function dosteps (siz)
   return i
 end
 
+-- JIT compilation can unpredictable allocate or reference objects
+-- (or traces itself). Disable it for this chunk for stable
+-- GC results.
+jit.off()
 assert(dosteps(0) > 10)
 assert(dosteps(6) < dosteps(2))
 assert(dosteps(10000) == 1)
 assert(collectgarbage("step", 1000000) == true)
 assert(collectgarbage("step", 1000000))
+jit.on()
 
 
 do
diff --git a/test/PUC-Lua-5.1-tests/literals.lua b/test/PUC-Lua-5.1-tests/literals.lua
index 01d84d5..ee16a3e 100644
--- a/test/PUC-Lua-5.1-tests/literals.lua
+++ b/test/PUC-Lua-5.1-tests/literals.lua
@@ -158,6 +158,10 @@ end
 
 
 -- testing decimal point locale
+-- LuaJIT doesn't use `strtod()` depended on the locale, unlike
+-- Lua does. See <src/lj_strscan.c> for more info.
+-- Tests are disabled for LuaJIT.
+--[[
 if os.setlocale("pt_BR") or os.setlocale("ptb") then
   assert(tonumber("3,4") == 3.4 and tonumber"3.4" == nil)
   assert(assert(loadstring("return 3.4"))() == 3.4)
@@ -171,6 +175,7 @@ else
   (Message or print)(
    '\a\n >>> pt_BR locale not available: skipping decimal point tests <<<\n\a')
 end
+--]]
 
 
 print('OK')
diff --git a/test/PUC-Lua-5.1-tests/main.lua b/test/PUC-Lua-5.1-tests/main.lua
index f520896..12f3981 100644
--- a/test/PUC-Lua-5.1-tests/main.lua
+++ b/test/PUC-Lua-5.1-tests/main.lua
@@ -65,9 +65,16 @@ a = string.format(a, progname)
 prepfile(a)
 RUN('lua "-e " -- %s a b c', prog)
 
-prepfile"assert(arg==nil)"
-prepfile("assert(arg)", otherprog)
-RUN("lua -l%s - < %s", prog, otherprog)
+-- test 'arg' availability in libraries
+-- LuaJIT v2.1.0-beta3 has extension from Lua 5.3:
+-- The argument table `arg` can be read (and modified)
+-- by `LUA_INIT` and `-e` chunks.
+-- See commit 92d9ff211ae864777a8580b5a7326d5f408161ce
+-- (Set arg table before evaluating LUA_INIT and -e chunks.).
+-- See also https://github.com/tarantool/tarantool/issues/5686.
+-- prepfile"assert(arg==nil)"
+-- prepfile("assert(arg)", otherprog)
+-- RUN("lua -l%s - < %s", prog, otherprog)
 
 prepfile""
 RUN("lua - < %s > %s", prog, out)
@@ -89,26 +96,35 @@ prepfile[[
 RUN("lua - < %s > %s", prog, out)
 checkout("1\tnil\n")
 
+-- Version and status are printed in stdout instead stderr since
+-- LuaJIT-2.0.0-beta11 (as it is not an error message).
+-- See commit 0bd1a66f2f055211ef55834ccebca3b82d03c735
+-- (Print version and JIT status to stdout, not stderr.).
+-- This behavior is the same as in Lua 5.2.
+-- See also https://github.com/tarantool/tarantool/issues/5687.
 prepfile[[
 = (6*2-6) -- ===
 a
 = 10
 print(a)
 = a]]
-RUN([[lua -e"_PROMPT='' _PROMPT2=''" -i < %s > %s]], prog, out)
-checkout("6\n10\n10\n\n")
+-- Behavior is different for LuaJIT. See the comment above.
+-- RUN([[lua -e"_PROMPT='' _PROMPT2=''" -i < %s > %s]], prog, out)
+-- checkout("6\n10\n10\n\n")
 
 prepfile("a = [[b\nc\nd\ne]]\n=a")
 print(prog)
-RUN([[lua -e"_PROMPT='' _PROMPT2=''" -i < %s > %s]], prog, out)
-checkout("b\nc\nd\ne\n\n")
+-- Behavior is different for LuaJIT. See the comment above.
+-- RUN([[lua -e"_PROMPT='' _PROMPT2=''" -i < %s > %s]], prog, out)
+-- checkout("b\nc\nd\ne\n\n")
 
 prompt = "alo"
 prepfile[[ --
 a = 2
 ]]
-RUN([[lua "-e_PROMPT='%s'" -i < %s > %s]], prompt, prog, out)
-checkout(string.rep(prompt, 3).."\n")
+-- Behavior is different for LuaJIT. See the comment above.
+-- RUN([[lua "-e_PROMPT='%s'" -i < %s > %s]], prompt, prog, out)
+-- checkout(string.rep(prompt, 3).."\n")
 
 s = [=[ --
 function f ( x )
@@ -126,19 +142,29 @@ assert( a == b )
 =f( 11 )  ]=]
 s = string.gsub(s, ' ', '\n\n')
 prepfile(s)
-RUN([[lua -e"_PROMPT='' _PROMPT2=''" -i < %s > %s]], prog, out)
-checkout("11\n1\t2\n\n")
+-- Behavior is different for LuaJIT. See the comment above.
+-- RUN([[lua -e"_PROMPT='' _PROMPT2=''" -i < %s > %s]], prog, out)
+-- checkout("11\n1\t2\n\n")
 
 prepfile[[#comment in 1st line without \n at the end]]
 RUN("lua %s", prog)
 
+-- test loading and running bytecode files.
+-- Loading bytecode with an extra header (BOM or "#") is disabled
+-- for security reasons since LuaJIT-2.0.0-beta10.
+-- For more information see comment for lj_lex_setup()
+-- in <src/lj_lex.c>.
+-- Also see commit 53a285c0c3544ff5dea7c67b741c3c2d06d22b47
+-- (Disable loading bytecode with an extra header (BOM or #!).).
+-- See also https://github.com/tarantool/tarantool/issues/5691.
 prepfile("#comment with a binary file\n"..string.dump(loadstring("print(1)")))
-RUN("lua %s > %s", prog, out)
-checkout("1\n")
+-- RUN("lua %s > %s", prog, out)
+-- checkout("1\n")
 
 prepfile("#comment with a binary file\r\n"..string.dump(loadstring("print(1)")))
-RUN("lua %s > %s", prog, out)
-checkout("1\n")
+-- Behavior is different for LuaJIT. See the comment above.
+-- RUN("lua %s > %s", prog, out)
+-- checkout("1\n")
 
 -- close Lua with an open file
 prepfile(string.format([[io.output(%q); io.write('alo')]], out))
diff --git a/test/PUC-Lua-5.1-tests/math.lua b/test/PUC-Lua-5.1-tests/math.lua
index 5076f38..b46a3f5 100644
--- a/test/PUC-Lua-5.1-tests/math.lua
+++ b/test/PUC-Lua-5.1-tests/math.lua
@@ -100,7 +100,12 @@ assert(math.abs(-10) == 10)
 assert(eq(math.atan2(1,0), math.pi/2))
 assert(math.ceil(4.5) == 5.0)
 assert(math.floor(4.5) == 4.0)
-assert(math.mod(10,3) == 1)
+-- In Lua 5.1 math.mod() is renamed to math.fmod() if build
+-- Lua 5.1 without flag `-DLUA_COMPAT_MOD`.
+-- LuaJIT also has math.fmod() instead math.mod() builtin.
+-- See also https://github.com/tarantool/tarantool/issues/5711.
+-- Test is disabled.
+-- assert(math.mod(10,3) == 1)
 assert(eq(math.sqrt(10)^2, 10))
 assert(eq(math.log10(2), math.log(2)/math.log(10)))
 assert(eq(math.exp(0), 1))
diff --git a/test/PUC-Lua-5.1-tests/nextvar.lua b/test/PUC-Lua-5.1-tests/nextvar.lua
index 7ceaa75..a63f97e 100644
--- a/test/PUC-Lua-5.1-tests/nextvar.lua
+++ b/test/PUC-Lua-5.1-tests/nextvar.lua
@@ -199,6 +199,12 @@ _G["xxx"] = 1
 assert(xxx==find("xxx"))
 print('+')
 
+-- In Lua 5.1 math.mod() is renamed to math.fmod() if build
+-- Lua 5.1 without flag `-DLUA_COMPAT_MOD`.
+-- LuaJIT also has math.fmod() instead math.mod() builtin.
+-- See also https://github.com/tarantool/tarantool/issues/5711.
+-- Test is disabled.
+--[=[
 a = {}
 for i=0,10000 do
   if math.mod(i,10) ~= 0 then
@@ -213,6 +219,7 @@ for i,v in pairs(a) do
 end
 assert(n.n == 9000)
 a = nil
+--]=]
 
 -- remove those 10000 new global variables
 for i=1,10000 do _G[i] = nil end
diff --git a/test/PUC-Lua-5.1-tests/pm.lua b/test/PUC-Lua-5.1-tests/pm.lua
index fa125dc..366a31c 100644
--- a/test/PUC-Lua-5.1-tests/pm.lua
+++ b/test/PUC-Lua-5.1-tests/pm.lua
@@ -223,7 +223,11 @@ assert(string.gsub("a alo b hi", "%w%w+", t) == "a ALO b HI")
 
 
 -- tests for gmatch
-assert(string.gfind == string.gmatch)
+-- In Lua 5.1 function string.gfind was renamed to string.gmatch.
+-- You can use it if Lua 5.1 is built with compile-time option
+-- `-DLUA_COMPAT_GFIND`.
+-- This builtin is removed from LuaJIT. Test is disabled.
+-- assert(string.gfind == string.gmatch)
 local a = 0
 for i in string.gmatch('abcde', '()') do assert(i == a+1); a=i end
 assert(a==6)
diff --git a/test/PUC-Lua-5.1-tests/strings.lua b/test/PUC-Lua-5.1-tests/strings.lua
index 237dbad..a97c888 100644
--- a/test/PUC-Lua-5.1-tests/strings.lua
+++ b/test/PUC-Lua-5.1-tests/strings.lua
@@ -102,7 +102,18 @@ print('+')
 
 x = '"ílo"\n\\'
 assert(string.format('%q%s', x, x) == '"\\"ílo\\"\\\n\\\\""ílo"\n\\')
-assert(string.format('%q', "\0") == [["\000"]])
+-- LuaJIT since v2.0.0-beta6 has extension from Lua 5.2:
+-- string.format(): %q reversible.
+-- In Lua 5.1 string.format() does not accept string values
+-- containing embedded zeros, except as arguments to the q option.
+-- In Lua 5.2 '\0' is not handled differently from other
+-- control chars in string.format('%q', ...).
+-- See commit 7cc981c14067d4b0e774a6bfb0acfc2f5c911f0d
+-- (string.format("%q", str) is now fully reversible
+-- (from Lua 5.2).).
+-- See also https://github.com/tarantool/tarantool/issues/5710.
+-- Test is disabled for LuaJIT for now.
+-- assert(string.format('%q', "\0") == [["\000"]])
 assert(string.format("\0%c\0%c%x\0", string.byte("á"), string.byte("b"), 140) ==
               "\0á\0b8c\0")
 assert(string.format('') == "")
@@ -152,6 +163,9 @@ local function trylocale (w)
   return false
 end
 
+-- LuaJIT doesn't compare strings by `strcoll`, like Lua 5.1 does.
+-- Tests are disabled for LuaJIT.
+--[[
 if not trylocale("collate")  then
   print("locale not supported")
 else
@@ -166,6 +180,7 @@ else
   assert(string.gsub("áÁéÉ", "%u", "x") == "áxéx")
   assert(string.upper"áÁé{xuxu}ção" == "ÁÁÉ{XUXU}ÇÃO")
 end
+--]]
 
 os.setlocale("C")
 assert(os.setlocale() == 'C')
diff --git a/test/PUC-Lua-5.1-tests/vararg.lua b/test/PUC-Lua-5.1-tests/vararg.lua
index ae068fa..e2de1ad 100644
--- a/test/PUC-Lua-5.1-tests/vararg.lua
+++ b/test/PUC-Lua-5.1-tests/vararg.lua
@@ -21,9 +21,14 @@ function vararg (...) return arg end
 
 local call = function (f, args) return f(unpack(args, 1, args.n)) end
 
-assert(f() == 0)
-assert(f({1,2,3}, 1, 2, 3) == 3)
-assert(f({"alo", nil, 45, f, nil}, "alo", nil, 45, f, nil) == 5)
+-- Lua 5.1 interprets ... in the vararg functions like additional
+-- first argument unlike LuaJIT does. All extra arguments is set
+-- into `arg` variable. This extension is from Lua 5.2.
+-- See also https://github.com/tarantool/tarantool/issues/5712.
+-- Test is disabled for LuaJIT.
+-- assert(f() == 0)
+-- assert(f({1,2,3}, 1, 2, 3) == 3)
+-- assert(f({"alo", nil, 45, f, nil}, "alo", nil, 45, f, nil) == 5)
 
 assert(c12(1,2)==55)
 a,b = assert(call(c12, {1,2}))
@@ -35,15 +40,18 @@ assert(not a)
 assert(c12(1,2,3) == false)
 local a = vararg(call(next, {_G,nil;n=2}))
 local b,c = next(_G)
-assert(a[1] == b and a[2] == c and a.n == 2)
+-- Test is disabled for LuaJIT for now. See the comment above.
+-- assert(a[1] == b and a[2] == c and a.n == 2)
 a = vararg(call(call, {c12, {1,2}}))
-assert(a.n == 2 and a[1] == 55 and a[2] == 2)
+-- Test is disabled for LuaJIT for now. See the comment above.
+-- assert(a.n == 2 and a[1] == 55 and a[2] == 2)
 a = call(print, {'+'})
 assert(a == nil)
 
 local t = {1, 10}
 function t:f (...) return self[arg[1]]+arg.n end
-assert(t:f(1,4) == 3 and t:f(2) == 11)
+-- Test is disabled for LuaJIT for now. See the comment above.
+-- assert(t:f(1,4) == 3 and t:f(2) == 11)
 print('+')
 
 lim = 20
-- 
2.28.0