tests/lapi: add builtin tests

The commit adds tests for Lua 5.1 builtin functions except the
following functions: `print`, `pcall`, `xpcall`, `type`.

Author: ligurio

tests/lapi/builtin_assert_test.lua

@@ -0,0 +1,27 @@
+--[[
+SPDX-License-Identifier: ISC
+Copyright (c) 2023-2025, Sergey Bronnikov.
+
+5.1 – Basic Functions
+https://www.lua.org/manual/5.1/manual.html
+
+Synopsis: assert(v [, message])
+]]
+
+local luzer = require("luzer")
+local test_lib = require("lib")
+local MAX_INT = test_lib.MAX_INT
+
+local function TestOneInput(buf)
+    local fdp = luzer.FuzzedDataProvider(buf)
+    local max_len = fdp:consume_integer(0, MAX_INT)
+    local message = fdp:consume_string(max_len)
+    local v = fdp:consume_boolean()
+    local ok, _ = pcall(assert, v, message)
+    assert(ok == v)
+end
+
+local args = {
+    artifact_prefix = "builtin_assert_",
+}
+luzer.Fuzz(TestOneInput, nil, args)

tests/lapi/builtin_collectgarbage_test.lua

@@ -0,0 +1,60 @@
+--[=[[
+SPDX-License-Identifier: ISC
+Copyright (c) 2023-2025, Sergey Bronnikov.
+
+5.1 – Basic Functions
+https://www.lua.org/manual/5.1/manual.html
+
+Synopsis: collectgarbage([opt [, arg]])
+]]=]
+
+local luzer = require("luzer")
+local test_lib = require("lib")
+
+local unpack = unpack or table.unpack
+
+local gc_mode = {
+    "collect",
+    "count",
+    "restart",
+    "step",
+    "stop",
+}
+
+if test_lib.lua_version() == "LuaJIT" then
+    table.insert(gc_mode, "setpause")
+    table.insert(gc_mode, "setstepmul")
+else
+    table.insert(gc_mode, "isrunning")
+    table.insert(gc_mode, "incremental")
+    table.insert(gc_mode, "generational")
+end
+
+local function TestOneInput(buf)
+    local fdp = luzer.FuzzedDataProvider(buf)
+    local mode = fdp:oneof(gc_mode)
+    local MAX_INT = test_lib.MAX_INT
+    local arg = {}
+    if mode == "step" or
+       mode == "setpause" or
+       mode == "setstepmul" then
+        table.insert(arg, fdp:consume_integer(0, MAX_INT))
+    end
+    -- This option can be followed by two numbers: the
+    -- garbage-collector minor multiplier and the major multiplier.
+    if mode == "generational" then
+        table.insert(arg, fdp:consume_integer(0, MAX_INT))
+    end
+    -- This option can be followed by three numbers: the
+    -- garbage-collector pause, the step multiplier, and the step
+    -- size
+    if mode == "incremental" then
+        table.insert(arg, fdp:consume_integer(0, MAX_INT))
+    end
+    collectgarbage(mode, unpack(arg))
+end
+
+local args = {
+    artifact_prefix = "builtin_collectgarbage_",
+}
+luzer.Fuzz(TestOneInput, nil, args)

tests/lapi/builtin_concat_test.lua

@@ -0,0 +1,55 @@
+--[[
+SPDX-License-Identifier: ISC
+Copyright (c) 2023-2025, Sergey Bronnikov.
+
+2.5.4 – Concatenation
+https://www.lua.org/manual/5.1/manual.html
+
+Recording of __concat in GC64 mode,
+https://github.com/LuaJIT/LuaJIT/issues/839
+
+Bug: Unbalanced Stack After Hot Instruction error on table concatenation,
+https://github.com/LuaJIT/LuaJIT/issues/690
+
+LJ_GC64: Fix lua_concat(),
+https://github.com/LuaJIT/LuaJIT/issues/881
+
+Buffer overflow in string concatenation,
+https://github.com/lua/lua/commit/5853c37a83ec66ccb45094f9aeac23dfdbcde671
+
+Wrong assert when reporting concatenation errors
+(manifests only when Lua is compiled in debug mode).
+https://www.lua.org/bugs.html#5.2.2-3
+
+Wrong error message in some concatenations,
+https://www.lua.org/bugs.html#5.1.2-5
+
+Concat metamethod converts numbers to strings,
+https://www.lua.org/bugs.html#5.1.1-8
+
+String concatenation may cause arithmetic overflow, leading to
+a buffer overflow,
+https://www.lua.org/bugs.html#5.0.2-1
+]]
+
+local luzer = require("luzer")
+local test_lib = require("lib")
+
+local function TestOneInput(buf)
+    local fdp = luzer.FuzzedDataProvider(buf)
+    local str = fdp:consume_string(test_lib.MAX_STR_LEN)
+    if str == nil then return -1 end
+    local str_chars = {}
+    str:gsub(".", function(c) table.insert(str_chars, c) end)
+
+    local str_concat = ""
+    for _, c in ipairs(str_chars) do
+        str_concat = str_concat .. c
+    end
+    assert(str_concat == str)
+end
+
+local args = {
+    artifact_prefix = "builtin_concat_",
+}
+luzer.Fuzz(TestOneInput, nil, args)

tests/lapi/builtin_dofile_test.lua

@@ -0,0 +1,30 @@
+--[[
+SPDX-License-Identifier: ISC
+Copyright (c) 2023-2025, Sergey Bronnikov.
+
+5.1 – Basic Functions
+https://www.lua.org/manual/5.1/manual.html
+
+Synopsis: dofile([filename])
+]]
+
+local luzer = require("luzer")
+local test_lib = require("lib")
+
+local function TestOneInput(buf)
+    local chunk_filename = os.tmpname()
+    local fh = io.open(chunk_filename, "w")
+    fh:write(buf)
+    fh:close()
+    pcall(dofile, chunk_filename)
+    os.remove(chunk_filename)
+end
+
+local args = {
+    artifact_prefix = "builtin_dofile_",
+}
+-- lj_bcread.c:123: bcread_byte: buffer read overflow
+if test_lib.lua_version() == "LuaJIT" then
+    args.only_ascii = 1
+end
+luzer.Fuzz(TestOneInput, nil, args)

tests/lapi/builtin_dostring_test.lua

@@ -0,0 +1,27 @@
+--[[
+SPDX-License-Identifier: ISC
+Copyright (c) 2023-2025, Sergey Bronnikov.
+
+5.1 – Basic Functions
+https://www.lua.org/manual/5.1/manual.html
+]]
+
+local luzer = require("luzer")
+local test_lib = require("lib")
+local MAX_INT = test_lib.MAX_INT
+
+local function TestOneInput(buf)
+    local fdp = luzer.FuzzedDataProvider(buf)
+    local max_len = fdp:consume_integer(0, MAX_INT)
+    local str = fdp:consume_string(max_len)
+    pcall(loadstring, str)
+end
+
+local args = {
+    artifact_prefix = "builtin_dostring_",
+}
+-- lj_bcread.c:123: bcread_byte: buffer read overflow
+if test_lib.lua_version() == "LuaJIT" then
+    args.only_ascii = 1
+end
+luzer.Fuzz(TestOneInput, nil, args)

tests/lapi/builtin_error_test.lua

@@ -0,0 +1,33 @@
+--[[
+SPDX-License-Identifier: ISC
+Copyright (c) 2023-2025, Sergey Bronnikov.
+
+5.1 – Basic Functions
+https://www.lua.org/manual/5.1/manual.html
+
+Synopsis: error(message [, level])
+]]
+
+local luzer = require("luzer")
+local test_lib = require("lib")
+local MAX_INT = test_lib.MAX_INT
+
+local function escape_pattern(text)
+    return (text:gsub("[-.+%[%]()$^%%?*]", "%%%1"))
+end
+
+local function TestOneInput(buf)
+    local fdp = luzer.FuzzedDataProvider(buf)
+    local level = fdp:consume_integer(0, MAX_INT)
+    local message_len = fdp:consume_integer(0, MAX_INT)
+    local message = fdp:consume_string(message_len)
+    local ok, err = pcall(error, message, level)
+    assert(ok == false)
+    -- Escape message to avoid error "invalid pattern capture".
+    assert(err:match(escape_pattern(message)) == message)
+end
+
+local args = {
+    artifact_prefix = "builtin_error_",
+}
+luzer.Fuzz(TestOneInput, nil, args)

tests/lapi/builtin_getfenv_test.lua

@@ -0,0 +1,46 @@
+--[[
+SPDX-License-Identifier: ISC
+Copyright (c) 2023-2025, Sergey Bronnikov.
+
+5.1 – Basic Functions
+https://www.lua.org/manual/5.1/manual.html
+
+debug.getfenv does not check whether it has an argument,
+https://www.lua.org/bugs.html#5.1.4-5
+
+module may change the environment of a C function,
+https://www.lua.org/bugs.html#5.1.3-11
+
+UBSan warning for too big/small getfenv/setfenv level,
+https://github.com/LuaJIT/LuaJIT/issues/1329
+
+Synopsis: getfenv([f])
+]]
+
+local luzer = require("luzer")
+local test_lib = require("lib")
+
+-- Lua 5.2: Functions setfenv and getfenv were removed, because
+-- of the changes in environments.
+if test_lib.lua_current_version_ge_than(5, 2) then
+    print("Unsupported version.")
+    os.exit(0)
+end
+
+local function TestOneInput(buf)
+    local fdp = luzer.FuzzedDataProvider(buf)
+    local level = fdp:consume_integer(0, test_lib.MAX_INT)
+    local fenv, err = pcall(getfenv, level)
+    if err then
+        return -1
+    end
+    local magic_str = fdp:consume_string(test_lib.MAX_STR_LEN)
+    fenv["magic"] = magic_str
+    setfenv(level, fenv)
+    assert(getfenv(level).magic == magic_str)
+end
+
+local args = {
+    artifact_prefix = "builtin_getfenv_",
+}
+luzer.Fuzz(TestOneInput, nil, args)

tests/lapi/builtin_getmetatable_test.lua

@@ -0,0 +1,33 @@
+--[[
+SPDX-License-Identifier: ISC
+Copyright (c) 2023-2025, Sergey Bronnikov.
+
+5.1 – Basic Functions
+https://www.lua.org/manual/5.1/manual.html
+
+Incorrect recording of getmetatable() for IO handlers,
+https://github.com/LuaJIT/LuaJIT/issues/1279
+
+Synopsis: getmetatable(object)
+]]
+
+local luzer = require("luzer")
+local test_lib = require("lib")
+
+local function TestOneInput(buf)
+    local tbl = {}
+    local fdp = luzer.FuzzedDataProvider(buf)
+    -- Build a random table and set a known key to it to check
+    -- it's presence in metatable.
+    local MAX_N = 100
+    local count = fdp:consume_integer(0, MAX_N)
+    local mt = fdp:consume_integers(test_lib.MIN_INT, test_lib.MAX_INT, count)
+    setmetatable(tbl, mt)
+    local metatable = getmetatable(tbl)
+    assert(test_lib.arrays_equal(metatable, mt))
+end
+
+local args = {
+    artifact_prefix = "builtin_getmetatable_",
+}
+luzer.Fuzz(TestOneInput, nil, args)

tests/lapi/builtin_ipairs_test.lua

@@ -0,0 +1,28 @@
+--[[
+SPDX-License-Identifier: ISC
+Copyright (c) 2023-2025, Sergey Bronnikov.
+
+5.1 – Basic Functions
+https://www.lua.org/manual/5.1/manual.html
+
+Synopsis: ipairs(t)
+]]
+
+local luzer = require("luzer")
+local test_lib = require("lib")
+
+local function TestOneInput(buf)
+    local fdp = luzer.FuzzedDataProvider(buf)
+    local MAX_N = 1000
+    local count = fdp:consume_integer(0, MAX_N)
+    local tbl = fdp:consume_integers(test_lib.MIN_INT, test_lib.MAX_INT, count)
+    for i, v in ipairs(tbl) do
+        assert(type(i) == "number")
+        assert(type(v) == "number")
+    end
+end
+
+local args = {
+    artifact_prefix = "builtin_ipairs_",
+}
+luzer.Fuzz(TestOneInput, nil, args)

tests/lapi/builtin_length_test.lua

@@ -0,0 +1,34 @@
+--[[
+SPDX-License-Identifier: ISC
+Copyright (c) 2023-2025, Sergey Bronnikov.
+
+2.5.5 – The Length Operator
+https://www.lua.org/manual/5.1/manual.html
+
+Table length computation overflows for sequences larger than
+2^31 elements, https://www.lua.org/bugs.html#5.3.4-3
+]]
+
+local luzer = require("luzer")
+local test_lib = require("lib")
+
+local unpack = unpack or table.unpack
+
+local function TestOneInput(buf)
+    local fdp = luzer.FuzzedDataProvider(buf)
+
+    local str = fdp:consume_string(test_lib.MAX_STR_LEN)
+    if str == nil then return -1 end
+    local str_chars = {}
+    str:gsub(".", function(c) table.insert(str_chars, c) end)
+
+    assert(#str == select("#", unpack(str_chars)))
+    assert(#str == string.len(str))
+    assert(#str == str:len())
+    assert(#str_chars == str:len())
+end
+
+local args = {
+    artifact_prefix = "builtin_length_",
+}
+luzer.Fuzz(TestOneInput, nil, args)