third_party/web_platform_tests/dom/nodes/CharacterData-appendData.html

<!DOCTYPE html>
<meta charset=utf-8>
<title>CharacterData.appendData</title>
<link rel=help href="https://dom.spec.whatwg.org/#dom-characterdata-appenddata">
<link rel=help href="https://dom.spec.whatwg.org/#dom-characterdata-data">
<script src="/resources/testharness.js"></script>
<script src="/resources/testharnessreport.js"></script>
<div id="log"></div>
<script>
function testNode(create, type) {
  test(function() {
    var node = create()
    assert_equals(node.data, "test")

    node.appendData("bar")
    assert_equals(node.data, "testbar")
  }, type + ".appendData('bar')")

  test(function() {
    var node = create()
    assert_equals(node.data, "test")

    node.appendData("")
    assert_equals(node.data, "test")
  }, type + ".appendData('')")

  test(function() {
    var node = create()
    assert_equals(node.data, "test")
    node.appendData(", append more 資料，測試資料");
    assert_equals(node.data, "test, append more 資料，測試資料");
    assert_equals(node.length, 25);
  }, type + ".appendData(non-ASCII)")

  test(function() {
    var node = create()
    assert_equals(node.data, "test")

    node.appendData(null)
    assert_equals(node.data, "testnull")
  }, type + ".appendData(null)")

  test(function() {
    var node = create()
    assert_equals(node.data, "test")

    node.appendData(undefined)
    assert_equals(node.data, "testundefined")
  }, type + ".appendData(undefined)")

  test(function() {
    var node = create()
    assert_equals(node.data, "test")

    node.appendData("", "bar")
    assert_equals(node.data, "test")
  }, type + ".appendData('', 'bar')")

  test(function() {
    var node = create()
    assert_equals(node.data, "test")

    assert_throws(new TypeError(), function() { node.appendData() });
    assert_equals(node.data, "test")
  }, type + ".appendData()")
}

testNode(function() { return document.createTextNode("test") }, "Text")
testNode(function() { return document.createComment("test") }, "Comment")
</script>