firefox/testing/web-platform/tests/css/CSS2/generated-content/content-159-ref.html

<!DOCTYPE html>
<meta charset="utf-8">
<title>CSS Reference</title>
<style>
    div {
        border: 2px solid blue;
    }
</style>
<body>
    <p>Test passes if there are 3 quotes (" ' ") in the blue box.</p>
    <div>" ' "</div>
</body>