content/base/test/test_meta_viewport4.html

<!DOCTYPE HTML>
<html>
<head>
  <meta charset="utf-8">
  <title>meta viewport test</title>
  <script type="application/javascript" src="/tests/SimpleTest/SimpleTest.js"></script>
  <link rel="stylesheet" type="text/css" href="/tests/SimpleTest/test.css"/>
  <meta name="viewport" content="initial-scale=1.0, user-scalable=no">
</head>
<body>
  <p>initial-scale=1.0, user-scalable=no</p>
  <script type="application/javascript;version=1.7">
    "use strict";

    SimpleTest.waitForExplicitFinish();

    let tests = [];

    tests.push(function test1() {
      SpecialPowers.pushPrefEnv({"set": [["browser.viewport.scaleRatio", 100]]},
        function() {
          let info = getViewportInfo(800, 480);
          is(info.defaultZoom, 1,     "initial zoom is set explicitly");
          is(info.width,       800,   "width fits the initial zoom level");
          is(info.height,      480,   "height fits the initial zoom level");
          is(info.autoSize,    true,  "initial-scale=1 enables autoSize");
          is(info.allowZoom,   false, "zooming is explicitly disabled");

          info = getViewportInfo(480, 800);
          is(info.defaultZoom, 1,     "initial zoom is still set explicitly");
          is(info.width,       480,   "width changes to match the displayWidth");
          is(info.height,      800,   "height changes to match the displayHeight");

          nextTest();
        });
    });

    tests.push(function test2() {
      SpecialPowers.pushPrefEnv({"set": [["browser.viewport.scaleRatio", 150]]},
        function() {
          let info = getViewportInfo(800, 480);
          is(info.defaultZoom, 1.5,   "initial zoom is adjusted for device pixel ratio");
          is(info.width,       533,   "width fits the initial zoom");
          is(info.height,      320,   "height fits the initial zoom");

          nextTest();
        });
    });

    function getViewportInfo(aDisplayWidth, aDisplayHeight) {
      let defaultZoom = {}, allowZoom = {}, minZoom = {}, maxZoom = {},
          width = {}, height = {}, autoSize = {};

      let cwu = SpecialPowers.getDOMWindowUtils(window);
      cwu.getViewportInfo(aDisplayWidth, aDisplayHeight, defaultZoom, allowZoom,
                          minZoom, maxZoom, width, height, autoSize);
      return {
        defaultZoom: defaultZoom.value,
        minZoom: minZoom.value,
        maxZoom: maxZoom.value,
        width: width.value,
        height: height.value,
        autoSize: autoSize.value,
        allowZoom: allowZoom.value
      };
    }

    function nextTest() {
      if (tests.length)
        (tests.shift())();
      else
        SimpleTest.finish();
    }
    addEventListener("load", nextTest);
  </script>
</body>
</html>