chromium/third_party/blink/web_tests/editing/pasteboard/text-selection.html

<!DOCTYPE html>
<html>
<body oncopy="copy(event)" onpaste="paste(event)">
<div id="text">This file tests if text selection is causing oncopy event to get fired. This test requires DRT.</div>
<div id="console"></div>

<script src="../editing.js"></script>
<script>

var oncopyCounter = 0;

function log(text)
{
    var console = document.getElementById('console');
    console.appendChild(document.createTextNode(text));
    console.appendChild(document.createElement('br'));
}

function copy(ev)
{
    ++oncopyCounter;
}

function runTest() {
    if (!window.testRunner)
        return;
    testRunner.dumpAsText();

    log("Selecting text with mouse, no copy events should occur:");
    log("Event count: " + oncopyCounter)

    var text = document.getElementById("text")
    eventSender.mouseMoveTo(text.offsetLeft, text.offsetTop);
    eventSender.mouseDown();
    eventSender.mouseMoveTo(text.offsetLeft + text.offsetWidth, text.offsetTop);
    eventSender.mouseUp();

    log("Copying text, 1 copy event should occur:");
    
    copyCommand();
    log("Event count: " + oncopyCounter);
}

runTest();

</script>
</body>
</html>