JCR-5230: improve diagnostics in IndexingQueueTest (#339)

Author: reschke

jackrabbit-core/src/test/java/org/apache/jackrabbit/core/query/lucene/IndexingQueueTest.java

@@ -150,7 +150,7 @@ public void testReaderUpToDate() throws Exception {
         try {
             FileUtil.delete(indexDir);
         } catch (IOException e) {
-            fail("Unable to delete index directory");
+            fail("Unable to delete index directory '" + indexDir + "': " + e.getMessage());
         }
 
         BlockingParser.unblock();

jackrabbit-data/src/main/java/org/apache/jackrabbit/core/fs/local/FileUtil.java

@@ -93,7 +93,7 @@ public static void delete(File f) throws IOException {
             }
         }
         if (!f.delete()) {
-            throw new IOException("Unable to delete " + f.getPath());
+            throw new IOException("Unable to delete '" + f.getPath() + "'");
         }
     }
 }