### Question:
UrlUtils { public static String addFirstSlash(String uri) { return StringUtils.prependSubstring(uri, "/"); }  static String trimSlashes(String string); static String getEncodedUrl(String url); static String removeFirstAndLastSlash(String uri); static String addFirstSlash(String uri); static String removeLastSlash(String uri); static String getHostIPAddress(String fqdn); static String getIpAddressFromUrl(String urlString);  }### Answer:
@Test public void addFirstSlash() { assertNull(UrlUtils.addFirstSlash(null)); String whiteSpace = " "; assertEquals("/", UrlUtils.addFirstSlash(whiteSpace)); String hasSlashes = " /blah/ "; assertEquals("/blah/", UrlUtils.addFirstSlash(hasSlashes)); }