Verifying that symlink target may be absolute.

core/src/test/java/hudson/UtilTest.java

@@ -187,6 +187,14 @@ public class UtilTest {
             
             // JENKINS-12331: either a bug in createSymlink or this isn't supposed to work: 
             //assertTrue(Util.isSymlink(new File(d,"anotherDir/link")));
+
+            File external = File.createTempFile("something", "");
+            try {
+                Util.createSymlink(d, external.getAbsolutePath(), "outside", l);
+                assertEquals(external.getAbsolutePath(), Util.resolveSymlink(new File(d, "outside")));
+            } finally {
+                assertTrue(external.delete());
+            }
         } finally {
             Util.deleteRecursive(d);
         }