#!/usr/bin/env ruby
require 'test/unit'
require File.dirname(__FILE__) + '/../test_helper'
require 'sass/script'

module Sass::Script::Functions
  def no_kw_args
    Sass::Script::String.new("no-kw-args")
  end

  def only_var_args(*args)
    Sass::Script::String.new("only-var-args("+args.map{|a| a.plus(Sass::Script::Number.new(1)).to_s }.join(", ")+")")
  end
  declare :only_var_args, [], :var_args => true

  def only_kw_args(kwargs)
    Sass::Script::String.new("only-kw-args(" + kwargs.keys.map {|a| a.to_s}.sort.join(", ") + ")")
  end
  declare :only_kw_args, [], :var_kwargs => true
end

module Sass::Script::Functions::UserFunctions
  def call_options_on_new_literal
    str = Sass::Script::String.new("foo")
    str.options[:foo]
    str
  end

  def user_defined
    Sass::Script::String.new("I'm a user-defined string!")
  end

  def _preceding_underscore
    Sass::Script::String.new("I'm another user-defined string!")
  end
end

module Sass::Script::Functions
  include Sass::Script::Functions::UserFunctions
end

class SassFunctionTest < Test::Unit::TestCase
  # Tests taken from:
  #   http://www.w3.org/Style/CSS/Test/CSS3/Color/20070927/html4/t040204-hsl-h-rotating-b.htm
  #   http://www.w3.org/Style/CSS/Test/CSS3/Color/20070927/html4/t040204-hsl-values-b.htm
  File.read(File.dirname(__FILE__) + "/data/hsl-rgb.txt").split("\n\n").each do |chunk|
    hsls, rgbs = chunk.strip.split("====")
    hsls.strip.split("\n").zip(rgbs.strip.split("\n")) do |hsl, rgb|
      hsl_method = "test_hsl: #{hsl} = #{rgb}"
      define_method(hsl_method) do
        assert_equal(evaluate(rgb), evaluate(hsl))
      end

      rgb_to_hsl_method = "test_rgb_to_hsl: #{rgb} = #{hsl}"
      define_method(rgb_to_hsl_method) do
        rgb_color = perform(rgb)
        hsl_color = perform(hsl)

        white = hsl_color.lightness == 100
        black = hsl_color.lightness == 0
        grayscale = white || black || hsl_color.saturation == 0

        assert_in_delta(hsl_color.hue, rgb_color.hue, 0.0001,
          "Hues should be equal") unless grayscale
        assert_in_delta(hsl_color.saturation, rgb_color.saturation, 0.0001,
          "Saturations should be equal") unless white || black
        assert_in_delta(hsl_color.lightness, rgb_color.lightness, 0.0001,
          "Lightnesses should be equal")
      end
    end
  end

  def test_hsl_kwargs
    assert_equal "#33cccc", evaluate("hsl($hue: 180, $saturation: 60%, $lightness: 50%)")
  end

  def test_hsl_checks_bounds
    assert_error_message("Saturation -114 must be between 0% and 100% for `hsl'", "hsl(10, -114, 12)");
    assert_error_message("Lightness 256 must be between 0% and 100% for `hsl'", "hsl(10, 10, 256%)");
  end

  def test_hsl_checks_types
    assert_error_message("\"foo\" is not a number for `hsl'", "hsl(\"foo\", 10, 12)");
    assert_error_message("\"foo\" is not a number for `hsl'", "hsl(10, \"foo\", 12)");
    assert_error_message("\"foo\" is not a number for `hsl'", "hsl(10, 10, \"foo\")");
  end

  def test_hsla
    assert_equal "rgba(51, 204, 204, 0.4)", evaluate("hsla(180, 60%, 50%, 0.4)")
    assert_equal "#33cccc", evaluate("hsla(180, 60%, 50%, 1)")
    assert_equal "rgba(51, 204, 204, 0)", evaluate("hsla(180, 60%, 50%, 0)")
    assert_equal "rgba(51, 204, 204, 0.4)", evaluate("hsla($hue: 180, $saturation: 60%, $lightness: 50%, $alpha: 0.4)")
  end

  def test_hsla_checks_bounds
    assert_error_message("Saturation -114 must be between 0% and 100% for `hsla'", "hsla(10, -114, 12, 1)");
    assert_error_message("Lightness 256 must be between 0% and 100% for `hsla'", "hsla(10, 10, 256%, 0)");
    assert_error_message("Alpha channel -0.1 must be between 0 and 1 for `hsla'", "hsla(10, 10, 10, -0.1)");
    assert_error_message("Alpha channel 1.1 must be between 0 and 1 for `hsla'", "hsla(10, 10, 10, 1.1)");
  end

  def test_hsla_checks_types
    assert_error_message("\"foo\" is not a number for `hsla'", "hsla(\"foo\", 10, 12, 0.3)");
    assert_error_message("\"foo\" is not a number for `hsla'", "hsla(10, \"foo\", 12, 0)");
    assert_error_message("\"foo\" is not a number for `hsla'", "hsla(10, 10, \"foo\", 1)");
    assert_error_message("\"foo\" is not a number for `hsla'", "hsla(10, 10, 10, \"foo\")");
  end

  def test_percentage
    assert_equal("50%",  evaluate("percentage(.5)"))
    assert_equal("100%", evaluate("percentage(1)"))
    assert_equal("25%",  evaluate("percentage(25px / 100px)"))
    assert_equal("50%",  evaluate("percentage($value: 0.5)"))
  end

  def test_percentage_checks_types
    assert_error_message("25px is not a unitless number for `percentage'", "percentage(25px)")
    assert_error_message("#cccccc is not a unitless number for `percentage'", "percentage(#ccc)")
    assert_error_message("\"string\" is not a unitless number for `percentage'", %Q{percentage("string")})
  end

  def test_round
    assert_equal("5",   evaluate("round(4.8)"))
    assert_equal("5px", evaluate("round(4.8px)"))
    assert_equal("5px", evaluate("round(5.49px)"))
    assert_equal("5px", evaluate("round($value: 5.49px)"))

    assert_error_message("#cccccc is not a number for `round'", "round(#ccc)")
  end

  def test_floor
    assert_equal("4",   evaluate("floor(4.8)"))
    assert_equal("4px", evaluate("floor(4.8px)"))
    assert_equal("4px", evaluate("floor($value: 4.8px)"))

    assert_error_message("\"foo\" is not a number for `floor'", "floor(\"foo\")")
  end

  def test_ceil
    assert_equal("5",   evaluate("ceil(4.1)"))
    assert_equal("5px", evaluate("ceil(4.8px)"))
    assert_equal("5px", evaluate("ceil($value: 4.8px)"))

    assert_error_message("\"a\" is not a number for `ceil'", "ceil(\"a\")")
  end

  def test_abs
    assert_equal("5",   evaluate("abs(-5)"))
    assert_equal("5px", evaluate("abs(-5px)"))
    assert_equal("5",   evaluate("abs(5)"))
    assert_equal("5px", evaluate("abs(5px)"))
    assert_equal("5px", evaluate("abs($value: 5px)"))

    assert_error_message("#aaaaaa is not a number for `abs'", "abs(#aaa)")
  end

  def test_rgb
    assert_equal("#123456", evaluate("rgb(18, 52, 86)"))
    assert_equal("#beaded", evaluate("rgb(190, 173, 237)"))
    assert_equal("#00ff7f", evaluate("rgb(0, 255, 127)"))
    assert_equal("#00ff7f", evaluate("rgb($red: 0, $green: 255, $blue: 127)"))
  end

  def test_rgb_percent
    assert_equal("#123456", evaluate("rgb(7.1%, 20.4%, 34%)"))
    assert_equal("#beaded", evaluate("rgb(74.7%, 173, 93%)"))
    assert_equal("#beaded", evaluate("rgb(190, 68%, 237)"))
    assert_equal("#00ff7f", evaluate("rgb(0%, 100%, 50%)"))
  end

  def test_rgb_tests_bounds
    assert_error_message("Color value 256 must be between 0 and 255 inclusive for `rgb'",
      "rgb(256, 1, 1)")
    assert_error_message("Color value 256 must be between 0 and 255 inclusive for `rgb'",
      "rgb(1, 256, 1)")
    assert_error_message("Color value 256 must be between 0 and 255 inclusive for `rgb'",
      "rgb(1, 1, 256)")
    assert_error_message("Color value 256 must be between 0 and 255 inclusive for `rgb'",
      "rgb(1, 256, 257)")
    assert_error_message("Color value -1 must be between 0 and 255 inclusive for `rgb'",
      "rgb(-1, 1, 1)")
  end

  def test_rgb_test_percent_bounds
    assert_error_message("Color value 100.1% must be between 0% and 100% inclusive for `rgb'",
      "rgb(100.1%, 0, 0)")
    assert_error_message("Color value -0.1% must be between 0% and 100% inclusive for `rgb'",
      "rgb(0, -0.1%, 0)")
    assert_error_message("Color value 101% must be between 0% and 100% inclusive for `rgb'",
      "rgb(0, 0, 101%)")
  end

  def test_rgb_tests_types
    assert_error_message("\"foo\" is not a number for `rgb'", "rgb(\"foo\", 10, 12)");
    assert_error_message("\"foo\" is not a number for `rgb'", "rgb(10, \"foo\", 12)");
    assert_error_message("\"foo\" is not a number for `rgb'", "rgb(10, 10, \"foo\")");
  end

  def test_rgba
    assert_equal("rgba(18, 52, 86, 0.5)", evaluate("rgba(18, 52, 86, 0.5)"))
    assert_equal("#beaded", evaluate("rgba(190, 173, 237, 1)"))
    assert_equal("rgba(0, 255, 127, 0)", evaluate("rgba(0, 255, 127, 0)"))
    assert_equal("rgba(0, 255, 127, 0)", evaluate("rgba($red: 0, $green: 255, $blue: 127, $alpha: 0)"))
  end

  def test_rgb_tests_bounds
    assert_error_message("Color value 256 must be between 0 and 255 inclusive for `rgba'",
      "rgba(256, 1, 1, 0.3)")
    assert_error_message("Color value 256 must be between 0 and 255 inclusive for `rgba'",
      "rgba(1, 256, 1, 0.3)")
    assert_error_message("Color value 256 must be between 0 and 255 inclusive for `rgba'",
      "rgba(1, 1, 256, 0.3)")
    assert_error_message("Color value 256 must be between 0 and 255 inclusive for `rgba'",
      "rgba(1, 256, 257, 0.3)")
    assert_error_message("Color value -1 must be between 0 and 255 inclusive for `rgba'",
      "rgba(-1, 1, 1, 0.3)")
    assert_error_message("Alpha channel -0.2 must be between 0 and 1 inclusive for `rgba'",
      "rgba(1, 1, 1, -0.2)")
    assert_error_message("Alpha channel 1.2 must be between 0 and 1 inclusive for `rgba'",
      "rgba(1, 1, 1, 1.2)")
  end

  def test_rgba_tests_types
    assert_error_message("\"foo\" is not a number for `rgba'", "rgba(\"foo\", 10, 12, 0.2)");
    assert_error_message("\"foo\" is not a number for `rgba'", "rgba(10, \"foo\", 12, 0.1)");
    assert_error_message("\"foo\" is not a number for `rgba'", "rgba(10, 10, \"foo\", 0)");
    assert_error_message("\"foo\" is not a number for `rgba'", "rgba(10, 10, 10, \"foo\")");
  end

  def test_rgba_with_color
    assert_equal "rgba(16, 32, 48, 0.5)", evaluate("rgba(#102030, 0.5)")
    assert_equal "rgba(0, 0, 255, 0.5)", evaluate("rgba(blue, 0.5)")
    assert_equal "rgba(0, 0, 255, 0.5)", evaluate("rgba($color: blue, $alpha: 0.5)")
  end

  def test_rgba_with_color_tests_types
    assert_error_message("\"foo\" is not a color for `rgba'", "rgba(\"foo\", 0.2)");
    assert_error_message("\"foo\" is not a number for `rgba'", "rgba(blue, \"foo\")");
  end

  def test_rgba_tests_num_args
    assert_error_message("wrong number of arguments (0 for 4) for `rgba'", "rgba()");
    assert_error_message("wrong number of arguments (1 for 4) for `rgba'", "rgba(blue)");
    assert_error_message("wrong number of arguments (3 for 4) for `rgba'", "rgba(1, 2, 3)");
    assert_error_message("wrong number of arguments (5 for 4) for `rgba'", "rgba(1, 2, 3, 0.4, 5)");
  end

  def test_red
    assert_equal("18", evaluate("red(#123456)"))
    assert_equal("18", evaluate("red($color: #123456)"))
  end

  def test_red_exception
    assert_error_message("12 is not a color for `red'", "red(12)")
  end

  def test_green
    assert_equal("52", evaluate("green(#123456)"))
    assert_equal("52", evaluate("green($color: #123456)"))
  end

  def test_green_exception
    assert_error_message("12 is not a color for `green'", "green(12)")
  end

  def test_blue
    assert_equal("86", evaluate("blue(#123456)"))
    assert_equal("86", evaluate("blue($color: #123456)"))
  end

  def test_blue_exception
    assert_error_message("12 is not a color for `blue'", "blue(12)")
  end

  def test_hue
    assert_equal("18deg", evaluate("hue(hsl(18, 50%, 20%))"))
    assert_equal("18deg", evaluate("hue($color: hsl(18, 50%, 20%))"))
  end

  def test_hue_exception
    assert_error_message("12 is not a color for `hue'", "hue(12)")
  end

  def test_saturation
    assert_equal("52%", evaluate("saturation(hsl(20, 52%, 20%))"))
    assert_equal("52%", evaluate("saturation(hsl(20, 52, 20%))"))
    assert_equal("52%", evaluate("saturation($color: hsl(20, 52, 20%))"))
  end

  def test_saturation_exception
    assert_error_message("12 is not a color for `saturation'", "saturation(12)")
  end

  def test_lightness
    assert_equal("86%", evaluate("lightness(hsl(120, 50%, 86%))"))
    assert_equal("86%", evaluate("lightness(hsl(120, 50%, 86))"))
    assert_equal("86%", evaluate("lightness($color: hsl(120, 50%, 86))"))
  end

  def test_lightness_exception
    assert_error_message("12 is not a color for `lightness'", "lightness(12)")
  end

  def test_alpha
    assert_equal("1", evaluate("alpha(#123456)"))
    assert_equal("0.34", evaluate("alpha(rgba(0, 1, 2, 0.34))"))
    assert_equal("0", evaluate("alpha(hsla(0, 1, 2, 0))"))
    assert_equal("0", evaluate("alpha($color: hsla(0, 1, 2, 0))"))
  end

  def test_alpha_exception
    assert_error_message("12 is not a color for `alpha'", "alpha(12)")
  end

  def test_opacify
    assert_equal("rgba(0, 0, 0, 0.75)", evaluate("opacify(rgba(0, 0, 0, 0.5), 0.25)"))
    assert_equal("rgba(0, 0, 0, 0.3)", evaluate("opacify(rgba(0, 0, 0, 0.2), 0.1)"))
    assert_equal("rgba(0, 0, 0, 0.7)", evaluate("fade-in(rgba(0, 0, 0, 0.2), 0.5px)"))
    assert_equal("black", evaluate("fade_in(rgba(0, 0, 0, 0.2), 0.8)"))
    assert_equal("black", evaluate("opacify(rgba(0, 0, 0, 0.2), 1)"))
    assert_equal("rgba(0, 0, 0, 0.2)", evaluate("opacify(rgba(0, 0, 0, 0.2), 0%)"))
    assert_equal("rgba(0, 0, 0, 0.2)", evaluate("opacify($color: rgba(0, 0, 0, 0.2), $amount: 0%)"))
    assert_equal("rgba(0, 0, 0, 0.2)", evaluate("fade-in($color: rgba(0, 0, 0, 0.2), $amount: 0%)"))
  end

  def test_opacify_tests_bounds
    assert_error_message("Amount -0.001 must be between 0 and 1 for `opacify'",
      "opacify(rgba(0, 0, 0, 0.2), -0.001)")
    assert_error_message("Amount 1.001 must be between 0 and 1 for `opacify'",
      "opacify(rgba(0, 0, 0, 0.2), 1.001)")
  end

  def test_opacify_tests_types
    assert_error_message("\"foo\" is not a color for `opacify'", "opacify(\"foo\", 10%)")
    assert_error_message("\"foo\" is not a number for `opacify'", "opacify(#fff, \"foo\")")
  end

  def test_transparentize
    assert_equal("rgba(0, 0, 0, 0.3)", evaluate("transparentize(rgba(0, 0, 0, 0.5), 0.2)"))
    assert_equal("rgba(0, 0, 0, 0.1)", evaluate("transparentize(rgba(0, 0, 0, 0.2), 0.1)"))
    assert_equal("rgba(0, 0, 0, 0.2)", evaluate("fade-out(rgba(0, 0, 0, 0.5), 0.3px)"))
    assert_equal("rgba(0, 0, 0, 0)", evaluate("fade_out(rgba(0, 0, 0, 0.2), 0.2)"))
    assert_equal("rgba(0, 0, 0, 0)", evaluate("transparentize(rgba(0, 0, 0, 0.2), 1)"))
    assert_equal("rgba(0, 0, 0, 0.2)", evaluate("transparentize(rgba(0, 0, 0, 0.2), 0)"))
    assert_equal("rgba(0, 0, 0, 0.2)", evaluate("transparentize($color: rgba(0, 0, 0, 0.2), $amount: 0)"))
    assert_equal("rgba(0, 0, 0, 0.2)", evaluate("fade-out($color: rgba(0, 0, 0, 0.2), $amount: 0)"))
  end

  def test_transparentize_tests_bounds
    assert_error_message("Amount -0.001 must be between 0 and 1 for `transparentize'",
      "transparentize(rgba(0, 0, 0, 0.2), -0.001)")
    assert_error_message("Amount 1.001 must be between 0 and 1 for `transparentize'",
      "transparentize(rgba(0, 0, 0, 0.2), 1.001)")
  end

  def test_transparentize_tests_types
    assert_error_message("\"foo\" is not a color for `transparentize'", "transparentize(\"foo\", 10%)")
    assert_error_message("\"foo\" is not a number for `transparentize'", "transparentize(#fff, \"foo\")")
  end

  def test_lighten
    assert_equal("#4d4d4d", evaluate("lighten(hsl(0, 0, 0), 30%)"))
    assert_equal("#ee0000", evaluate("lighten(#800, 20%)"))
    assert_equal("white", evaluate("lighten(#fff, 20%)"))
    assert_equal("white", evaluate("lighten(#800, 100%)"))
    assert_equal("#880000", evaluate("lighten(#800, 0%)"))
    assert_equal("rgba(238, 0, 0, 0.5)", evaluate("lighten(rgba(136, 0, 0, 0.5), 20%)"))
    assert_equal("rgba(238, 0, 0, 0.5)", evaluate("lighten($color: rgba(136, 0, 0, 0.5), $amount: 20%)"))
  end

  def test_lighten_tests_bounds
    assert_error_message("Amount -0.001 must be between 0% and 100% for `lighten'",
      "lighten(#123, -0.001)")
    assert_error_message("Amount 100.001 must be between 0% and 100% for `lighten'",
      "lighten(#123, 100.001)")
  end

  def test_lighten_tests_types
    assert_error_message("\"foo\" is not a color for `lighten'", "lighten(\"foo\", 10%)")
    assert_error_message("\"foo\" is not a number for `lighten'", "lighten(#fff, \"foo\")")
  end

  def test_darken
    assert_equal("#ff6a00", evaluate("darken(hsl(25, 100, 80), 30%)"))
    assert_equal("#220000", evaluate("darken(#800, 20%)"))
    assert_equal("black", evaluate("darken(#000, 20%)"))
    assert_equal("black", evaluate("darken(#800, 100%)"))
    assert_equal("#880000", evaluate("darken(#800, 0%)"))
    assert_equal("rgba(34, 0, 0, 0.5)", evaluate("darken(rgba(136, 0, 0, 0.5), 20%)"))
    assert_equal("rgba(34, 0, 0, 0.5)", evaluate("darken($color: rgba(136, 0, 0, 0.5), $amount: 20%)"))
  end

  def test_darken_tests_bounds
    assert_error_message("Amount -0.001 must be between 0% and 100% for `darken'",
      "darken(#123, -0.001)")
    assert_error_message("Amount 100.001 must be between 0% and 100% for `darken'",
      "darken(#123, 100.001)")
  end

  def test_darken_tests_types
    assert_error_message("\"foo\" is not a color for `darken'", "darken(\"foo\", 10%)")
    assert_error_message("\"foo\" is not a number for `darken'", "darken(#fff, \"foo\")")
  end

  def test_saturate
    assert_equal("#d9f2d9", evaluate("saturate(hsl(120, 30, 90), 20%)"))
    assert_equal("#9e3f3f", evaluate("saturate(#855, 20%)"))
    assert_equal("black", evaluate("saturate(#000, 20%)"))
    assert_equal("white", evaluate("saturate(#fff, 20%)"))
    assert_equal("#33ff33", evaluate("saturate(#8a8, 100%)"))
    assert_equal("#88aa88", evaluate("saturate(#8a8, 0%)"))
    assert_equal("rgba(158, 63, 63, 0.5)", evaluate("saturate(rgba(136, 85, 85, 0.5), 20%)"))
    assert_equal("rgba(158, 63, 63, 0.5)", evaluate("saturate($color: rgba(136, 85, 85, 0.5), $amount: 20%)"))
  end

  def test_saturate_tests_bounds
    assert_error_message("Amount -0.001 must be between 0% and 100% for `saturate'",
      "saturate(#123, -0.001)")
    assert_error_message("Amount 100.001 must be between 0% and 100% for `saturate'",
      "saturate(#123, 100.001)")
  end

  def test_saturate_tests_types
    assert_error_message("\"foo\" is not a color for `saturate'", "saturate(\"foo\", 10%)")
    assert_error_message("\"foo\" is not a number for `saturate'", "saturate(#fff, \"foo\")")
  end

  def test_desaturate
    assert_equal("#e3e8e3", evaluate("desaturate(hsl(120, 30, 90), 20%)"))
    assert_equal("#726b6b", evaluate("desaturate(#855, 20%)"))
    assert_equal("black", evaluate("desaturate(#000, 20%)"))
    assert_equal("white", evaluate("desaturate(#fff, 20%)"))
    assert_equal("#999999", evaluate("desaturate(#8a8, 100%)"))
    assert_equal("#88aa88", evaluate("desaturate(#8a8, 0%)"))
    assert_equal("rgba(114, 107, 107, 0.5)", evaluate("desaturate(rgba(136, 85, 85, 0.5), 20%)"))
    assert_equal("rgba(114, 107, 107, 0.5)", evaluate("desaturate($color: rgba(136, 85, 85, 0.5), $amount: 20%)"))
  end

  def test_desaturate_tests_bounds
    assert_error_message("Amount -0.001 must be between 0% and 100% for `desaturate'",
      "desaturate(#123, -0.001)")
    assert_error_message("Amount 100.001 must be between 0% and 100% for `desaturate'",
      "desaturate(#123, 100.001)")
  end

  def test_desaturate_tests_types
    assert_error_message("\"foo\" is not a color for `desaturate'", "desaturate(\"foo\", 10%)")
    assert_error_message("\"foo\" is not a number for `desaturate'", "desaturate(#fff, \"foo\")")
  end

  def test_adjust_hue
    assert_equal("#deeded", evaluate("adjust-hue(hsl(120, 30, 90), 60deg)"))
    assert_equal("#ededde", evaluate("adjust-hue(hsl(120, 30, 90), -60deg)"))
    assert_equal("#886a11", evaluate("adjust-hue(#811, 45deg)"))
    assert_equal("black", evaluate("adjust-hue(#000, 45deg)"))
    assert_equal("white", evaluate("adjust-hue(#fff, 45deg)"))
    assert_equal("#88aa88", evaluate("adjust-hue(#8a8, 360deg)"))
    assert_equal("#88aa88", evaluate("adjust-hue(#8a8, 0deg)"))
    assert_equal("rgba(136, 106, 17, 0.5)", evaluate("adjust-hue(rgba(136, 17, 17, 0.5), 45deg)"))
    assert_equal("rgba(136, 106, 17, 0.5)", evaluate("adjust-hue($color: rgba(136, 17, 17, 0.5), $degrees: 45deg)"))
  end

  def test_adjust_hue_tests_types
    assert_error_message("\"foo\" is not a color for `adjust-hue'", "adjust-hue(\"foo\", 10%)")
    assert_error_message("\"foo\" is not a number for `adjust-hue'", "adjust-hue(#fff, \"foo\")")
  end

  def test_adjust_color
    # HSL
    assert_equal(evaluate("hsl(180, 30, 90)"),
      evaluate("adjust-color(hsl(120, 30, 90), $hue: 60deg)"))
    assert_equal(evaluate("hsl(120, 50, 90)"),
      evaluate("adjust-color(hsl(120, 30, 90), $saturation: 20%)"))
    assert_equal(evaluate("hsl(120, 30, 60)"),
      evaluate("adjust-color(hsl(120, 30, 90), $lightness: -30%)"))
    # RGB
    assert_equal(evaluate("rgb(15, 20, 30)"),
      evaluate("adjust-color(rgb(10, 20, 30), $red: 5)"))
    assert_equal(evaluate("rgb(10, 15, 30)"),
      evaluate("adjust-color(rgb(10, 20, 30), $green: -5)"))
    assert_equal(evaluate("rgb(10, 20, 40)"),
      evaluate("adjust-color(rgb(10, 20, 30), $blue: 10)"))
    # Alpha
    assert_equal(evaluate("hsla(120, 30, 90, 0.65)"),
      evaluate("adjust-color(hsl(120, 30, 90), $alpha: -0.35)"))
    assert_equal(evaluate("rgba(10, 20, 30, 0.9)"),
      evaluate("adjust-color(rgba(10, 20, 30, 0.4), $alpha: 0.5)"))

    # HSL composability
    assert_equal(evaluate("hsl(180, 20, 90)"),
      evaluate("adjust-color(hsl(120, 30, 90), $hue: 60deg, $saturation: -10%)"))
    assert_equal(evaluate("hsl(180, 20, 95)"),
      evaluate("adjust-color(hsl(120, 30, 90), $hue: 60deg, $saturation: -10%, $lightness: 5%)"))
    assert_equal(evaluate("hsla(120, 20, 95, 0.3)"),
      evaluate("adjust-color(hsl(120, 30, 90), $saturation: -10%, $lightness: 5%, $alpha: -0.7)"))

    # RGB composability
    assert_equal(evaluate("rgb(15, 20, 29)"),
      evaluate("adjust-color(rgb(10, 20, 30), $red: 5, $blue: -1)"))
    assert_equal(evaluate("rgb(15, 45, 29)"),
      evaluate("adjust-color(rgb(10, 20, 30), $red: 5, $green: 25, $blue: -1)"))
    assert_equal(evaluate("rgba(10, 25, 29, 0.7)"),
      evaluate("adjust-color(rgb(10, 20, 30), $green: 5, $blue: -1, $alpha: -0.3)"))

    # HSL range restriction
    assert_equal(evaluate("hsl(120, 30, 90)"),
      evaluate("adjust-color(hsl(120, 30, 90), $hue: 720deg)"))
    assert_equal(evaluate("hsl(120, 0, 90)"),
      evaluate("adjust-color(hsl(120, 30, 90), $saturation: -90%)"))
    assert_equal(evaluate("hsl(120, 30, 100)"),
      evaluate("adjust-color(hsl(120, 30, 90), $lightness: 30%)"))

    # RGB range restriction
    assert_equal(evaluate("rgb(255, 20, 30)"),
      evaluate("adjust-color(rgb(10, 20, 30), $red: 250)"))
    assert_equal(evaluate("rgb(10, 0, 30)"),
      evaluate("adjust-color(rgb(10, 20, 30), $green: -30)"))
    assert_equal(evaluate("rgb(10, 20, 0)"),
      evaluate("adjust-color(rgb(10, 20, 30), $blue: -40)"))
  end

  def test_adjust_color_tests_types
    assert_error_message("\"foo\" is not a color for `adjust-color'", "adjust-color(foo, $hue: 10)")
    # HSL
    assert_error_message("$hue: \"foo\" is not a number for `adjust-color'",
      "adjust-color(blue, $hue: foo)")
    assert_error_message("$saturation: \"foo\" is not a number for `adjust-color'",
      "adjust-color(blue, $saturation: foo)")
    assert_error_message("$lightness: \"foo\" is not a number for `adjust-color'",
      "adjust-color(blue, $lightness: foo)")
    # RGB
    assert_error_message("$red: \"foo\" is not a number for `adjust-color'",
      "adjust-color(blue, $red: foo)")
    assert_error_message("$green: \"foo\" is not a number for `adjust-color'",
      "adjust-color(blue, $green: foo)")
    assert_error_message("$blue: \"foo\" is not a number for `adjust-color'",
      "adjust-color(blue, $blue: foo)")
    # Alpha
    assert_error_message("$alpha: \"foo\" is not a number for `adjust-color'",
      "adjust-color(blue, $alpha: foo)")
  end

  def test_adjust_color_tests_arg_range
    # HSL
    assert_error_message("$saturation: Amount 101% must be between -100% and 100% for `adjust-color'",
      "adjust-color(blue, $saturation: 101%)")
    assert_error_message("$saturation: Amount -101% must be between -100% and 100% for `adjust-color'",
      "adjust-color(blue, $saturation: -101%)")
    assert_error_message("$lightness: Amount 101% must be between -100% and 100% for `adjust-color'",
      "adjust-color(blue, $lightness: 101%)")
    assert_error_message("$lightness: Amount -101% must be between -100% and 100% for `adjust-color'",
      "adjust-color(blue, $lightness: -101%)")
    # RGB
    assert_error_message("$red: Amount 256 must be between -255 and 255 for `adjust-color'",
      "adjust-color(blue, $red: 256)")
    assert_error_message("$red: Amount -256 must be between -255 and 255 for `adjust-color'",
      "adjust-color(blue, $red: -256)")
    assert_error_message("$green: Amount 256 must be between -255 and 255 for `adjust-color'",
      "adjust-color(blue, $green: 256)")
    assert_error_message("$green: Amount -256 must be between -255 and 255 for `adjust-color'",
      "adjust-color(blue, $green: -256)")
    assert_error_message("$blue: Amount 256 must be between -255 and 255 for `adjust-color'",
      "adjust-color(blue, $blue: 256)")
    assert_error_message("$blue: Amount -256 must be between -255 and 255 for `adjust-color'",
      "adjust-color(blue, $blue: -256)")
    # Alpha
    assert_error_message("$alpha: Amount 1.1 must be between -1 and 1 for `adjust-color'",
      "adjust-color(blue, $alpha: 1.1)")
    assert_error_message("$alpha: Amount -1.1 must be between -1 and 1 for `adjust-color'",
      "adjust-color(blue, $alpha: -1.1)")
  end

  def test_adjust_color_argument_errors
    assert_error_message("Unknown argument $hoo (260deg) for `adjust-color'",
      "adjust-color(blue, $hoo: 260deg)")
    assert_error_message("Cannot specify HSL and RGB values for a color at the same time for `adjust-color'",
      "adjust-color(blue, $hue: 120deg, $red: 10)");
    assert_error_message("10px is not a keyword argument for `adjust_color'",
      "adjust-color(blue, 10px)")
    assert_error_message("10px is not a keyword argument for `adjust_color'",
      "adjust-color(blue, 10px, 20px)")
    assert_error_message("10px is not a keyword argument for `adjust_color'",
      "adjust-color(blue, 10px, $hue: 180deg)")
  end

  def test_scale_color
    # HSL
    assert_equal(evaluate("hsl(120, 51, 90)"),
      evaluate("scale-color(hsl(120, 30, 90), $saturation: 30%)"))
    assert_equal(evaluate("hsl(120, 30, 76.5)"),
      evaluate("scale-color(hsl(120, 30, 90), $lightness: -15%)"))
    # RGB
    assert_equal(evaluate("rgb(157, 20, 30)"),
      evaluate("scale-color(rgb(10, 20, 30), $red: 60%)"))
    assert_equal(evaluate("rgb(10, 38.8, 30)"),
      evaluate("scale-color(rgb(10, 20, 30), $green: 8%)"))
    assert_equal(evaluate("rgb(10, 20, 20)"),
      evaluate("scale-color(rgb(10, 20, 30), $blue: -(1/3)*100%)"))
    # Alpha
    assert_equal(evaluate("hsla(120, 30, 90, 0.86)"),
      evaluate("scale-color(hsl(120, 30, 90), $alpha: -14%)"))
    assert_equal(evaluate("rgba(10, 20, 30, 0.82)"),
      evaluate("scale-color(rgba(10, 20, 30, 0.8), $alpha: 10%)"))

    # HSL composability
    assert_equal(evaluate("hsl(120, 51, 76.5)"),
      evaluate("scale-color(hsl(120, 30, 90), $saturation: 30%, $lightness: -15%)"))
    assert_equal(evaluate("hsla(120, 51, 90, 0.2)"),
      evaluate("scale-color(hsl(120, 30, 90), $saturation: 30%, $alpha: -80%)"))

    # RGB composability
    assert_equal(evaluate("rgb(157, 38.8, 30)"),
      evaluate("scale-color(rgb(10, 20, 30), $red: 60%, $green: 8%)"))
    assert_equal(evaluate("rgb(157, 38.8, 20)"),
      evaluate("scale-color(rgb(10, 20, 30), $red: 60%, $green: 8%, $blue: -(1/3)*100%)"))
    assert_equal(evaluate("rgba(10, 38.8, 20, 0.55)"),
      evaluate("scale-color(rgba(10, 20, 30, 0.5), $green: 8%, $blue: -(1/3)*100%, $alpha: 10%)"))

    # Extremes
    assert_equal(evaluate("hsl(120, 100, 90)"),
      evaluate("scale-color(hsl(120, 30, 90), $saturation: 100%)"))
    assert_equal(evaluate("hsl(120, 30, 90)"),
      evaluate("scale-color(hsl(120, 30, 90), $saturation: 0%)"))
    assert_equal(evaluate("hsl(120, 0, 90)"),
      evaluate("scale-color(hsl(120, 30, 90), $saturation: -100%)"))
  end

  def test_scale_color_tests_types
    assert_error_message("\"foo\" is not a color for `scale-color'", "scale-color(foo, $red: 10%)")
    # HSL
    assert_error_message("$saturation: \"foo\" is not a number for `scale-color'",
      "scale-color(blue, $saturation: foo)")
    assert_error_message("$lightness: \"foo\" is not a number for `scale-color'",
      "scale-color(blue, $lightness: foo)")
    # RGB
    assert_error_message("$red: \"foo\" is not a number for `scale-color'",
      "scale-color(blue, $red: foo)")
    assert_error_message("$green: \"foo\" is not a number for `scale-color'",
      "scale-color(blue, $green: foo)")
    assert_error_message("$blue: \"foo\" is not a number for `scale-color'",
      "scale-color(blue, $blue: foo)")
    # Alpha
    assert_error_message("$alpha: \"foo\" is not a number for `scale-color'",
      "scale-color(blue, $alpha: foo)")
  end

  def test_scale_color_argument_errors
    # Range
    assert_error_message("$saturation: Amount 101% must be between -100% and 100% for `scale-color'",
      "scale-color(blue, $saturation: 101%)")
    assert_error_message("$red: Amount -101% must be between -100% and 100% for `scale-color'",
      "scale-color(blue, $red: -101%)")
    assert_error_message("$alpha: Amount -101% must be between -100% and 100% for `scale-color'",
      "scale-color(blue, $alpha: -101%)")

    # Unit
    assert_error_message("$saturation: Amount 80 must be a % (e.g. 80%) for `scale-color'",
      "scale-color(blue, $saturation: 80)")
    assert_error_message("$alpha: Amount 0.5 must be a % (e.g. 0.5%) for `scale-color'",
      "scale-color(blue, $alpha: 0.5)")

    # Unknown argument
    assert_error_message("Unknown argument $hue (80%) for `scale-color'", "scale-color(blue, $hue: 80%)")

    # Non-keyword arg
    assert_error_message("10px is not a keyword argument for `scale_color'", "scale-color(blue, 10px)")

    # HSL/RGB
    assert_error_message("Cannot specify HSL and RGB values for a color at the same time for `scale-color'",
      "scale-color(blue, $lightness: 10%, $red: 20%)");
  end

  def test_change_color
    # HSL
    assert_equal(evaluate("hsl(195, 30, 90)"),
      evaluate("change-color(hsl(120, 30, 90), $hue: 195deg)"))
    assert_equal(evaluate("hsl(120, 50, 90)"),
      evaluate("change-color(hsl(120, 30, 90), $saturation: 50%)"))
    assert_equal(evaluate("hsl(120, 30, 40)"),
      evaluate("change-color(hsl(120, 30, 90), $lightness: 40%)"))
    # RGB
    assert_equal(evaluate("rgb(123, 20, 30)"),
      evaluate("change-color(rgb(10, 20, 30), $red: 123)"))
    assert_equal(evaluate("rgb(10, 234, 30)"),
      evaluate("change-color(rgb(10, 20, 30), $green: 234)"))
    assert_equal(evaluate("rgb(10, 20, 198)"),
      evaluate("change-color(rgb(10, 20, 30), $blue: 198)"))
    # Alpha
    assert_equal(evaluate("rgba(10, 20, 30, 0.76)"),
      evaluate("change-color(rgb(10, 20, 30), $alpha: 0.76)"))

    # HSL composability
    assert_equal(evaluate("hsl(56, 30, 47)"),
      evaluate("change-color(hsl(120, 30, 90), $hue: 56deg, $lightness: 47%)"))
    assert_equal(evaluate("hsla(56, 30, 47, 0.9)"),
      evaluate("change-color(hsl(120, 30, 90), $hue: 56deg, $lightness: 47%, $alpha: 0.9)"))
  end

  def test_change_color_tests_types
    assert_error_message("\"foo\" is not a color for `change-color'", "change-color(foo, $red: 10%)")
    # HSL
    assert_error_message("$saturation: \"foo\" is not a number for `change-color'",
      "change-color(blue, $saturation: foo)")
    assert_error_message("$lightness: \"foo\" is not a number for `change-color'",
      "change-color(blue, $lightness: foo)")
    # RGB
    assert_error_message("$red: \"foo\" is not a number for `change-color'", "change-color(blue, $red: foo)")
    assert_error_message("$green: \"foo\" is not a number for `change-color'", "change-color(blue, $green: foo)")
    assert_error_message("$blue: \"foo\" is not a number for `change-color'", "change-color(blue, $blue: foo)")
    # Alpha
    assert_error_message("$alpha: \"foo\" is not a number for `change-color'", "change-color(blue, $alpha: foo)")
  end

  def test_change_color_argument_errors
    # Range
    assert_error_message("Saturation must be between 0 and 100 for `change-color'",
      "change-color(blue, $saturation: 101%)")
    assert_error_message("Lightness must be between 0 and 100 for `change-color'",
      "change-color(blue, $lightness: 101%)")
    assert_error_message("Red value must be between 0 and 255 for `change-color'",
      "change-color(blue, $red: -1)")
    assert_error_message("Green value must be between 0 and 255 for `change-color'",
      "change-color(blue, $green: 256)")
    assert_error_message("Blue value must be between 0 and 255 for `change-color'",
      "change-color(blue, $blue: 500)")

    # Unknown argument
    assert_error_message("Unknown argument $hoo (80%) for `change-color'", "change-color(blue, $hoo: 80%)")

    # Non-keyword arg
    assert_error_message("10px is not a keyword argument for `change_color'", "change-color(blue, 10px)")

    # HSL/RGB
    assert_error_message("Cannot specify HSL and RGB values for a color at the same time for `change-color'",
      "change-color(blue, $lightness: 10%, $red: 120)");
  end

  def test_mix
    assert_equal("#7f007f", evaluate("mix(#f00, #00f)"))
    assert_equal("#7f7f7f", evaluate("mix(#f00, #0ff)"))
    assert_equal("#7f9055", evaluate("mix(#f70, #0aa)"))
    assert_equal("#3f00bf", evaluate("mix(#f00, #00f, 25%)"))
    assert_equal("rgba(63, 0, 191, 0.75)", evaluate("mix(rgba(255, 0, 0, 0.5), #00f)"))
    assert_equal("red", evaluate("mix(#f00, #00f, 100%)"))
    assert_equal("blue", evaluate("mix(#f00, #00f, 0%)"))
    assert_equal("rgba(255, 0, 0, 0.5)", evaluate("mix(#f00, transparentize(#00f, 1))"))
    assert_equal("rgba(0, 0, 255, 0.5)", evaluate("mix(transparentize(#f00, 1), #00f)"))
    assert_equal("red", evaluate("mix(#f00, transparentize(#00f, 1), 100%)"))
    assert_equal("blue", evaluate("mix(transparentize(#f00, 1), #00f, 0%)"))
    assert_equal("rgba(0, 0, 255, 0)", evaluate("mix(#f00, transparentize(#00f, 1), 0%)"))
    assert_equal("rgba(255, 0, 0, 0)", evaluate("mix(transparentize(#f00, 1), #00f, 100%)"))
    assert_equal("rgba(255, 0, 0, 0)", evaluate("mix($color-1: transparentize(#f00, 1), $color-2: #00f, $weight: 100%)"))
  end

  def test_mix_tests_types
    assert_error_message("\"foo\" is not a color for `mix'", "mix(\"foo\", #f00, 10%)")
    assert_error_message("\"foo\" is not a color for `mix'", "mix(#f00, \"foo\", 10%)")
    assert_error_message("\"foo\" is not a number for `mix'", "mix(#f00, #baf, \"foo\")")
  end

  def test_mix_tests_bounds
    assert_error_message("Weight -0.001 must be between 0% and 100% for `mix'",
      "mix(#123, #456, -0.001)")
    assert_error_message("Weight 100.001 must be between 0% and 100% for `mix'",
      "mix(#123, #456, 100.001)")
  end

  def test_grayscale
    assert_equal("#bbbbbb", evaluate("grayscale(#abc)"))
    assert_equal("gray", evaluate("grayscale(#f00)"))
    assert_equal("gray", evaluate("grayscale(#00f)"))
    assert_equal("white", evaluate("grayscale(white)"))
    assert_equal("black", evaluate("grayscale(black)"))
    assert_equal("black", evaluate("grayscale($color: black)"))
  end

  def tets_grayscale_tests_types
    assert_error_message("\"foo\" is not a color for `grayscale'", "grayscale(\"foo\")")
  end

  def test_complement
    assert_equal("#ccbbaa", evaluate("complement(#abc)"))
    assert_equal("aqua", evaluate("complement(red)"))
    assert_equal("red", evaluate("complement(aqua)"))
    assert_equal("white", evaluate("complement(white)"))
    assert_equal("black", evaluate("complement(black)"))
    assert_equal("black", evaluate("complement($color: black)"))
  end

  def tets_complement_tests_types
    assert_error_message("\"foo\" is not a color for `complement'", "complement(\"foo\")")
  end

  def test_invert
    assert_equal("#112233", evaluate("invert(#edc)"))
    assert_equal("rgba(245, 235, 225, 0.5)", evaluate("invert(rgba(10, 20, 30, 0.5))"))
  end

  def test_invert_tests_types
    assert_error_message("\"foo\" is not a color for `invert'", "invert(\"foo\")")
  end

  def test_unquote
    assert_equal('foo', evaluate('unquote("foo")'))
    assert_equal('foo', evaluate('unquote(foo)'))
    assert_equal('foo', evaluate('unquote($string: foo)'))
  end

  def test_quote
    assert_equal('"foo"', evaluate('quote(foo)'))
    assert_equal('"foo"', evaluate('quote("foo")'))
    assert_equal('"foo"', evaluate('quote($string: "foo")'))
  end

  def test_quote_tests_type
    assert_error_message("#ff0000 is not a string for `quote'", "quote(#f00)")
  end

  def test_user_defined_function
    assert_equal("I'm a user-defined string!", evaluate("user_defined()"))
  end

  def test_user_defined_function_with_preceding_underscore
    assert_equal("I'm another user-defined string!", evaluate("_preceding_underscore()"))
    assert_equal("I'm another user-defined string!", evaluate("-preceding-underscore()"))
  end

  def test_options_on_new_literals_fails
    assert_error_message(<<MSG, "call-options-on-new-literal()")
The #options attribute is not set on this Sass::Script::String.
  This error is probably occurring because #to_s was called
  on this literal within a custom Sass function without first
  setting the #option attribute.
MSG
  end

  def test_type_of
    assert_equal("string", evaluate("type-of(\"asdf\")"))
    assert_equal("string", evaluate("type-of(asdf)"))
    assert_equal("number", evaluate("type-of(1px)"))
    assert_equal("bool", evaluate("type-of(true)"))
    assert_equal("color", evaluate("type-of(#fff)"))
    assert_equal("color", evaluate("type-of($value: #fff)"))
  end

  def test_unit
    assert_equal(%Q{""}, evaluate("unit(100)"))
    assert_equal(%Q{"px"}, evaluate("unit(100px)"))
    assert_equal(%Q{"em*px"}, evaluate("unit(10px * 5em)"))
    assert_equal(%Q{"em*px"}, evaluate("unit(5em * 10px)"))
    assert_equal(%Q{"em*px/cm*rem"}, evaluate("unit(10px * 5em / 30cm / 1rem)"))
    assert_equal(%Q{"px"}, evaluate("unit($number: 100px)"))
    assert_error_message("#ff0000 is not a number for `unit'", "unit(#f00)")
  end

  def test_unitless
    assert_equal(%Q{true}, evaluate("unitless(100)"))
    assert_equal(%Q{false}, evaluate("unitless(100px)"))
    assert_equal(%Q{false}, evaluate("unitless($number: 100px)"))
    assert_error_message("#ff0000 is not a number for `unitless'", "unitless(#f00)")
  end

  def test_comparable
    assert_equal(%Q{true}, evaluate("comparable(2px, 1px)"))
    assert_equal(%Q{true}, evaluate("comparable(10cm, 3mm)"))
    assert_equal(%Q{false}, evaluate("comparable(100px, 3em)"))
    assert_equal(%Q{false}, evaluate("comparable($number-1: 100px, $number-2: 3em)"))
    assert_error_message("#ff0000 is not a number for `comparable'", "comparable(#f00, 1px)")
    assert_error_message("#ff0000 is not a number for `comparable'", "comparable(1px, #f00)")
  end

  def test_length
    assert_equal("5", evaluate("length(1 2 3 4 5)"))
    assert_equal("4", evaluate("length((foo, bar, baz, bip))"))
    assert_equal("3", evaluate("length((foo, bar, baz bip))"))
    assert_equal("3", evaluate("length((foo, bar, (baz, bip)))"))
    assert_equal("1", evaluate("length(#f00)"))
    assert_equal("0", evaluate("length(())"))
    assert_equal("4", evaluate("length(1 2 () 3)"))
  end

  def test_nth
    assert_equal("1", evaluate("nth(1 2 3, 1)"))
    assert_equal("2", evaluate("nth(1 2 3, 2)"))
    assert_equal("3", evaluate("nth((1, 2, 3), 3)"))
    assert_equal("foo", evaluate("nth(foo, 1)"))
    assert_equal("bar baz", evaluate("nth(foo (bar baz) bang, 2)"))
    assert_error_message("List index 0 must be greater than or equal to 1 for `nth'", "nth(foo, 0)")
    assert_error_message("List index -10 must be greater than or equal to 1 for `nth'", "nth(foo, -10)")
    assert_error_message("List index 1.5 must be an integer for `nth'", "nth(foo, 1.5)")
    assert_error_message("List index is 5 but list is only 4 items long for `nth'", "nth(1 2 3 4, 5)")
    assert_error_message("List index is 2 but list is only 1 item long for `nth'", "nth(foo, 2)")
    assert_error_message("List index is 1 but list has no items for `nth'", "nth((), 1)")
  end

  def test_join
    assert_equal("1 2 3", evaluate("join(1 2, 3)"))
    assert_equal("1 2 3", evaluate("join(1, 2 3)"))
    assert_equal("1 2 3 4", evaluate("join(1 2, 3 4)"))
    assert_equal("true", evaluate("(1 2 3 4) == join(1 2, 3 4)"))
    assert_equal("false", evaluate("(1 2 (3 4)) == join(1 2, 3 4)"))
    assert_equal("1, 2, 3", evaluate("join((1, 2), 3)"))
    assert_equal("1, 2, 3", evaluate("join(1, (2, 3))"))
    assert_equal("1, 2, 3, 4", evaluate("join((1, 2), (3, 4))"))
    assert_equal("true", evaluate("(1, 2, 3, 4) == join((1, 2), (3, 4))"))
    assert_equal("false", evaluate("(1, 2, (3, 4)) == join((1, 2), (3, 4))"))

    assert_equal("1 2", evaluate("join(1, 2)"))
    assert_equal("1 2 3 4", evaluate("join(1 2, (3, 4))"))
    assert_equal("1, 2, 3, 4", evaluate("join((1, 2), 3 4)"))

    assert_equal("1 2", evaluate("join(1, 2, auto)"))
    assert_equal("1, 2, 3, 4", evaluate("join(1 2, 3 4, comma)"))
    assert_equal("1 2 3 4", evaluate("join((1, 2), (3, 4), space)"))
    assert_equal("1, 2", evaluate("join(1, 2, comma)"))

    assert_equal("1 2", evaluate("join(1 2, ())"))
    assert_equal("1, 2", evaluate("join((1, 2), ())"))
    assert_equal("true", evaluate("(1 2) == join(1 2, ())"))
    assert_equal("true", evaluate("(1, 2) == join((1, 2), ())"))
    assert_equal("false", evaluate("(1 2 ()) == join(1 2, ())"))
    assert_equal("false", evaluate("(1, 2, ()) == join((1, 2), ())"))

    assert_equal("1 2", evaluate("join((), 1 2)"))
    assert_equal("1, 2", evaluate("join((), (1, 2))"))
    assert_equal("true", evaluate("(1 2) == join((), 1 2)"))
    assert_equal("true", evaluate("(1, 2) == join((), (1, 2))"))
    assert_equal("false", evaluate("(1 2 ()) == join((), 1 2)"))
    assert_equal("false", evaluate("(1, 2, ()) == join((), (1, 2))"))

    assert_error_message("Separator name must be space, comma, or auto for `join'", "join(1, 2, baboon)")
  end

  def test_append
    assert_equal("1 2 3", evaluate("append(1 2, 3)"))
    assert_equal("1 2 3 4", evaluate("append(1 2, 3 4)"))
    assert_equal("false", evaluate("(1 2 3 4) == append(1 2, 3 4)"))
    assert_equal("true", evaluate("(1 2 (3 4)) == append(1 2, 3 4)"))
    assert_equal("1, 2, 3", evaluate("append((1, 2), 3)"))
    assert_equal("1, 2, 3, 4", evaluate("append((1, 2), (3, 4))"))
    assert_equal("false", evaluate("(1, 2, 3, 4) == append((1, 2), (3, 4))"))
    assert_equal("true", evaluate("(1, 2, (3, 4)) == append((1, 2), (3, 4))"))

    assert_equal("1 2", evaluate("append(1, 2)"))
    assert_equal("1 2 3, 4", evaluate("append(1 2, (3, 4))"))
    assert_equal("true", evaluate("(1 2 (3, 4)) == append(1 2, (3, 4))"))
    assert_equal("1, 2, 3 4", evaluate("append((1, 2), 3 4)"))
    assert_equal("true", evaluate("(1, 2, 3 4) == append((1, 2), 3 4)"))

    assert_equal("1 2", evaluate("append(1, 2, auto)"))
    assert_equal("1, 2, 3 4", evaluate("append(1 2, 3 4, comma)"))
    assert_equal("1 2 3, 4", evaluate("append((1, 2), (3, 4), space)"))
    assert_equal("1, 2", evaluate("append(1, 2, comma)"))

    assert_equal("1 2", evaluate("append(1 2, ())"))
    assert_equal("1, 2", evaluate("append((1, 2), ())"))
    assert_equal("true", evaluate("(1 2 ()) == append(1 2, ())"))
    assert_equal("true", evaluate("(1, 2, ()) == append((1, 2), ())"))

    assert_equal("1 2", evaluate("append((), 1 2)"))
    assert_equal("1, 2", evaluate("append((), (1, 2))"))
    assert_equal("false", evaluate("(1 2) == append((), 1 2)"))
    assert_equal("true", evaluate("(1 2) == nth(append((), 1 2), 1)"))

    assert_error_message("Separator name must be space, comma, or auto for `append'", "append(1, 2, baboon)")
  end

  def test_zip
    assert_equal("1 3 5, 2 4 6", evaluate("zip(1 2, 3 4, 5 6)"))
    assert_equal("1 4 7, 2 5 8", evaluate("zip(1 2 3, 4 5 6, 7 8)"))
  end

  def test_index
    assert_equal("1", evaluate("index(1px solid blue, 1px)"))
    assert_equal("2", evaluate("index(1px solid blue, solid)"))
    assert_equal("3", evaluate("index(1px solid blue, #00f)"))
    assert_equal("false", evaluate("index(1px solid blue, 1em)"))
    assert_equal("false", evaluate("index(1px solid blue, notfound)"))
  end

  def test_if
    assert_equal("1px", evaluate("if(true, 1px, 2px)"))
    assert_equal("2px", evaluate("if(false, 1px, 2px)"))
  end

  def test_keyword_args_rgb
    assert_equal(%Q{white}, evaluate("rgb($red: 255, $green: 255, $blue: 255)"))
  end

  def test_keyword_args_rgba
    assert_equal(%Q{rgba(255, 255, 255, 0.5)}, evaluate("rgba($red: 255, $green: 255, $blue: 255, $alpha: 0.5)"))
    assert_equal(%Q{rgba(255, 255, 255, 0.5)}, evaluate("rgba($color: #fff, $alpha: 0.5)"))
  end

  def test_keyword_args_rgba_with_extra_args
    assert_equal(%Q{rgba(255, 255, 255, 0.5)}, evaluate("rgba($red: 255, $green: 255, $blue: 255, $alpha: 0.5, $extra: error)"))
  rescue Sass::SyntaxError => e
    assert_equal("Function rgba doesn't take an argument named $extra", e.message)
  end

  def test_keyword_args_must_have_signature
    evaluate("no-kw-args($fake: value)")
  rescue Sass::SyntaxError => e
    assert_equal("Function no_kw_args doesn't support keyword arguments", e.message)
  end

  def test_keyword_args_with_missing_argument
    evaluate("rgb($red: 255, $green: 255)")
  rescue Sass::SyntaxError => e
    assert_equal("Function rgb requires an argument named $blue", e.message)
  end

  def test_only_var_args
    assert_equal "only-var-args(2px, 3px, 4px)", evaluate("only-var-args(1px, 2px, 3px)")
  end

  def test_only_kw_args
    assert_equal "only-kw-args(a, b, c)", evaluate("only-kw-args($a: 1, $b: 2, $c: 3)")
  end

  private

  def evaluate(value)
    Sass::Script::Parser.parse(value, 0, 0).perform(Sass::Environment.new).to_s
  end

  def perform(value)
    Sass::Script::Parser.parse(value, 0, 0).perform(Sass::Environment.new)
  end

  def assert_error_message(message, value)
    evaluate(value)
    flunk("Error message expected but not raised: #{message}")
  rescue Sass::SyntaxError => e
    assert_equal(message, e.message)
  end

end
