LayoutTests/plugins/unsupported-plugin.html

<!DOCTYPE html>
<html>
<body>
<script src= "../resources/testharness.js"></script>
<script src= "../resources/testharnessreport.js"></script>
<script>
if (window.testRunner)
    testRunner.setPluginSupportedMode("none");
</script>
<p>A console log message should appear stating the plugin is unsupported.</p>
<embed id="plugin" type="application/x-webkit-test-netscape"></embed>

<script>
var test = async_test("Testing unsupported plug-in");
test.step(() => {
    if (!window.internals) {
       test.done();
       return;
    }
    var counter = 0;
    setInterval(test.step_func(() => {
        assert_true(++counter < 20, "Test timed out");
        let text = internals.unavailablePluginReplacementText(plugin);
        if (!text)
            return;
        assert_equals(text, "Unsupported Plug-in");
        test.done();
    }), 50);
});
</script>
</body>
</html>