### Question:
ST_Loc extends STBase { public String parent() { int indexOf = loc.lastIndexOf('/'); if (indexOf == -1) { return ""; } return loc.substring(0, indexOf); } ST_Loc(String path); static ST_Loc getInstance(String loc); static ST_Loc getInstance(Element e); String getLoc(); ST_Loc setLoc(String loc); String[] split(); String parent(); String getFileName(); ST_Loc cat(String p2); ST_Loc cat(ST_Loc loc); boolean endWith(String suffix); @Override String toString();  }### Answer:
@Test void parent() { ST_Loc loc = new ST_Loc("Doc_9/Pages/Page_0/Content.xml"); assertEquals("Doc_9/Pages/Page_0", loc.parent()); loc = new ST_Loc("Content.xml"); assertEquals("", loc.parent()); }