bstringData(5, 0) })
    assert_throws_dom("IndexSizeError", function() { node.substringData(6, 0) })
    assert_throws_dom("IndexSizeError", function() { node.substringData(-1, 0) })
  }, type + ".substringData() with invalid offset")

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

    assert_equals(node.substringData(0, 1), "t")
    assert_equals(node.substringData(1, 1), "e")
    assert_equals(node.substringData(2, 1), "s")
    assert_equals(node.substringData(3, 1), "t