CSS text-overflow: ellipsis; not working?

.app a {  height: 18px;  width: 140px;  padding: 0;  overflow: hidden;  position: relative;  margin: 0 5px 0 5px;  text-align: center;  text-decoration: none;  text-overflow: ellipsis;  white-space: nowrap;  color: #000;}

<div class="app"><a href="">Test Test Test Test Test Test</a></div>