sandbox.lua/spec/sandbox_spec.lua

local sandbox = require 'sandbox'

describe('sandbox.run', function()

  describe('when handling base cases', function()

    it('can run harmless strings', function()
      local r = sandbox.run("return 'hello'")
      assert.equal(r, 'hello')
    end)

    if sandbox.bytecode_blocked then
      it('rejects bytecode', function()
        local fn = function() end
        assert.error(function() sandbox.run(string.dump(fn)) end)
      end)
    else
      it('accepts bytecode (PUC Rio 5.1)', function()
        local fn = function() end
        assert.has.no.error(function() sandbox.run(string.dump(fn)) end)
      end)
    end

    it('has access to safe methods', function()
      assert.equal(10,      sandbox.run("return tonumber('10')"))
      assert.equal('HELLO', sandbox.run("return string.upper('hello')"))
      assert.equal(1,       sandbox.run("local a = {3,2,1}; table.sort(a); return a[1]"))
      assert.equal(10,      sandbox.run("return math.max(1,10)"))
    end)

    it('does not allow access to not-safe stuff', function()
      assert.error(function() sandbox.run('return setmetatable({}, {})') end)
      assert.error(function() sandbox.run('return string.rep("hello", 5)') end)
    end)

    it('does return multiple values', function()
      local result = { sandbox.run("return 'hello', 'world'") }
      assert.same({ 'hello', 'world' }, result)
    end)
  end)

  describe('when handling string.rep', function()
    it('does not allow pesky string:rep', function()
      assert.error(function() sandbox.run('return ("hello"):rep(5)') end)
    end)

    it('restores the value of string.rep', function()
      sandbox.run("")
      assert.equal('hellohello', string.rep('hello', 2))
    end)

    it('restores string.rep even if there is an error', function()
      assert.error(function() sandbox.run("error('foo')") end)
      assert.equal('hellohello', string.rep('hello', 2))
    end)

    it('passes parameters to the code', function()
      assert.equal(sandbox.run("local a, b = ...; return a + b", {}, 1,2), 3)
    end)
  end)


  describe('when the sandboxed code tries to modify the base environment', function()

    it('does not allow modifying the modules', function()
      assert.error(function() sandbox.run("string.foo = 1") end)
      assert.error(function() sandbox.run("string.char = 1") end)
    end)

    it('does not persist modifications of base functions', function()
      sandbox.run('error = function() end')
      assert.error(function() sandbox.run("error('this should be raised')") end)
    end)

    it('does not persist modification to base functions even when they are provided by the base env', function()
      local env = {['next'] = 'hello'}
      sandbox.run('next = "bye"', { env=env })
      assert.equal(env['next'], 'hello')
    end)
  end)


  if sandbox.quota_supported then
    describe('when given infinite loops', function()
      it('throws an error with infinite loops', function()
        assert.error(function() sandbox.run("while true do end") end)
      end)

      it('restores string.rep even after a while true', function()
        assert.error(function() sandbox.run("while true do end") end)
        assert.equal('hellohello', string.rep('hello', 2))
      end)

      it('accepts a quota param', function()
        assert.has_no.errors(function() sandbox.run("for i=1,100 do end") end)
        assert.error(function() sandbox.run("for i=1,100 do end", {quota = 20}) end)
      end)

      it('does not use quotes if the quote param is false', function()
        assert.has_no.errors(function() sandbox.run("for i=1,1000000 do end", {quota = false}) end)
      end)
    end)
  else
    it('throws an error when trying to use the quota option in an unsupported environment (LuaJIT)', function()
      assert.error(function() sandbox.run("", {quota = 20}) end)
    end)
  end


  describe('when given an env option', function()
    it('is available on the sandboxed env as the _G variable', function()
      local env = {foo = 1}
      assert.equal(1, sandbox.run("return foo", {env = env}))
      assert.equal(1, sandbox.run("return _G.foo", {env = env}))
    end)

    it('does not hide base env', function()
      assert.equal('HELLO', sandbox.run("return string.upper(foo)", {env = {foo = 'hello'}}))
    end)

    it('cannot modify the env', function()
      local env = {foo = 1}
      sandbox.run("foo = 2", {env = env})
      assert.equal(env.foo, 1)
    end)

    it('uses the env metatable, if it exists', function()
      local env1 = { foo = 1 }
      local env2 = { bar = 2 }
      setmetatable(env2, { __index = env1 })
      assert.equal(3, sandbox.run("return foo + bar", { env = env2 }))
    end)

    it('can override the base env', function()
      local env = { tostring = function(x) return "hello " .. x end }
      assert.equal("hello peter", sandbox.run("return tostring('peter')", { env = env }))
    end)
  end)

end)