css/css-color/system-color-consistency.html

<!DOCTYPE html>
<meta charset="utf-8">
<title>CSS Color 4: System color consistency</title>
<link rel="author" title="Jan Keitel" href="mailto:jkeitel@google.com">
<link rel="help" href="https://www.w3.org/TR/css-color-4/#css-system-colors">
<meta name="assert" content="computed style of form elements is consistent with definition of system colors">
<script src="/resources/testharness.js"></script>
<script src="/resources/testharnessreport.js"></script>
<script src="/css/support/computed-testcommon.js"></script>
<div style="display: none">
  <div id="target"></div>
  <!-- Reference elements -->
  <!-- Buttons -->
  <div id="buttons">
    <button name="button"></button><input type="submit" name="submit button">
    <input type="reset" name="reset button"><input type="color" name="color picker">
  </div>
  <!-- Input elements -->
  <div id="fields">
    <input type="text" name="text field"><input type="password" name="password field">
    <input type="email" name="email field"><input type="number" name="number field">
    <input type="date" name="date field">
    <textarea name="text area"></textarea>
  </div>
  <mark id="mark">Marked text</mark>
  <!-- Link -->
  <a href="#" id="link">Link</a>
  <div id="canvas" style="color: CanvasText; background-color: Canvas">Canvas Colors</mark>
</div>
<script>
  function test_not_canvas(color, colorScheme) {
    test(function() {
      let target = document.getElementById("target");
      target.style.color = color;

      let canvas = document.getElementById("canvas");
      assert_not_equals(getComputedStyle(target).color, getComputedStyle(canvas).backgroundColor, `${color} should not match Canvas`);
    }, `${color} should not match Canvas in ${colorScheme} mode`);
  }

  ['light', 'dark'].forEach(colorScheme => {
    document.documentElement.style.colorScheme = colorScheme;

    // Buttons
    for (let element of document.getElementById("buttons").children) {
      style = getComputedStyle(element);
      test_computed_value('color', 'ButtonBorder', style.getPropertyValue('border-color'), `resolves to the same color as the border-color of a ${element.name} (${colorScheme})`);
      test_computed_value('color', 'ButtonFace', style.getPropertyValue('background-color'), `resolves to the same color as the background-color of a ${element.name} (${colorScheme})`);
      test_computed_value('color', 'ButtonText', style.getPropertyValue('color'), `resolves to the same color as text on a ${element.name} (${colorScheme})`);
    }

    // CanvasText
    style = getComputedStyle(document.getElementsByTagName('html')[0]);
    test_computed_value('color', 'CanvasText', style.getPropertyValue('color'), `has the same color as the color of the html element (${colorScheme})`);

    // Field and FieldText
    for (let element of document.getElementById("fields").children) {
      style = getComputedStyle(element);
      test_computed_value('color', 'Field', style.getPropertyValue('background-color'), `resolves to the same color as the background-color of a ${element.name} (${colorScheme})`);
      test_computed_value('color', 'FieldText', style.getPropertyValue('color'), `resolves to the same color as text on a ${element.name} (${colorScheme})`);
    }

    // Mark and MarkText
    style = getComputedStyle(document.getElementById('mark'));
    test_computed_value('color', 'Mark', style.getPropertyValue('background-color'), `has the same color as the background-color of a mark element (${colorScheme})`);
    test_computed_value('color', 'MarkText', style.getPropertyValue('color'), `has the same color as the color of a mark element (${colorScheme})`);

    // LinkText
    style = getComputedStyle(document.getElementById('link'));
    test_computed_value('color', 'LinkText', style.getPropertyValue('color'), `has the same color as the color of an anchor element (${colorScheme})`);

    // These colors are only text colors and do not have corresponding
    // backgrounds, so they should not match the canvas background (as
    // otherwise they'd be invisible)
    test_not_canvas("LinkText", colorScheme);
    test_not_canvas("ActiveText", colorScheme);
    test_not_canvas("VisitedText", colorScheme);
  });
</script>