LayoutTests/fast/forms/input-autofilled.html

<!DOCTYPE html>
<html>
<head>
    <style>
    input {
      color: #FFFFFF;
      background-color: #FFFFFF;
    }
    form:has(input:autofill) {
        background-color: green;
        color: white;
    }
    </style>
</head>
<body>
    This tests that foreground and background colors properly change for autofilled inputs.<br>
    <form name="form" id="form">
        <input type="text" id="input" value="Field value" />
    </form>
    <script src="../../resources/testharness.js"></script>
    <script src="../../resources/testharnessreport.js"></script>
    <script>
    test(() => {
        testElement(input);
    }, "Testing input style changing with UA stylesheet");
    test(() => {
        testElement(form);
    }, "Testing form style changing with :has() selector");

    function testElement(element) {
        let computedStyle = getComputedStyle(element);
        let originalForeground = computedStyle.color;
        let originalBackground = computedStyle.backgroundColor;

        if (window.internals)
            window.internals.setAutofilled(input, true);

        // Both the foreground and background colors should change when autofilled.
        computedStyle = getComputedStyle(element);
        assert_not_equals(computedStyle.color, originalForeground, "Text color should change when autofilled.");
        assert_not_equals(computedStyle.backgroundColor, originalBackground, "Background color should change when autofilled.")

        if (window.internals)
            window.internals.setAutofilled(input, false);

        // Colors should be restored.
        computedStyle = getComputedStyle(element);
        assert_equals(computedStyle.color, originalForeground, "Text color should be restored");
        assert_equals(computedStyle.backgroundColor, originalBackground, "Background color should be restored")
    }
    </script>
</body>
</html>