ectActual instanceof DOMRect);
    assert_not_equals(caretRectActual, caretPosition.getClientRect(), "CaretPosition.getClientRect() should return a new DOMRect every time");
    assert_equals(caretRectActual.x, caretRectExpected.x);
    assert_equals(caretRectActual.y, caretRectExpected.y);
    assert_equals(caretRectActual.width, 0, "Caret range should be collapsed");
    assert_equals(caretRectActual.height, caretRectExpected.height);
  }, "CaretRange.getClientRect() should return a DOMRect that matches o