<!DOCTYPE HTML> <html> <!-- https://bugzilla.mozilla.org/show_bug.cgi?id=513439 --> <head> <title>Test for Bug 513439</title> <script type="application/javascript" src="/tests/SimpleTest/SimpleTest.js"></script> <link rel="stylesheet" type="text/css" href="/tests/SimpleTest/test.css"/> </head> <body> <a target="_blank" href="https://bugzilla.mozilla.org/show_bug.cgi?id=513439">Mozilla Bug 513439</a> <p id="display"></p> <div id="content" style="display: none"> </div> <pre id="test"> <script type="application/javascript"> /** Test for Bug 513439 **/ SimpleTest.waitForExplicitFinish(); var domWindowUtils = SpecialPowers.DOMWindowUtils; SpecialPowers.pushPrefEnv({set: [["layout.css.devPixelsPerPx", "2"]]}, () => { is(domWindowUtils.screenPixelsPerCSSPixel, 2, "devPixelsPerPx wasn't set correctly"); SpecialPowers.pushPrefEnv({set: [["layout.css.devPixelsPerPx", "1.5"]]}, () => { is(domWindowUtils.screenPixelsPerCSSPixel, 1.5, "devPixelsPerPx wasn't set correctly"); SimpleTest.finish(); }); }); </script> </pre> </body> </html>