/** Test that an empty dir will be removed during cleaning. */
 @Test
 public void testCleanNotEmptyGrandParentDir() throws Exception {
   String expResult = "0c40ffacd15b0f66d5081a93407d3ff5e3c65a71";
   Path grandparent = rootDir.toPath().resolve("0c");
   Path parent = grandparent.resolve("40ffacd15b0f66d5081a93407d3ff5e3c65a71");
   Path other = grandparent.resolve("40ffacd15b0f66d5081a93407d3ff5e3c65a81");
   Files.createDirectories(other);
   Path expectedContent = parent.resolve("content");
   assertFalse(expectedContent + " shouldn't exist", Files.exists(expectedContent));
   assertFalse(parent + " shouldn't exist", Files.exists(parent));
   byte[] result;
   try (InputStream stream = getResourceAsStream("overlay.xhtml")) {
     assertThat(repository.hasContent(HashUtil.hexStringToByteArray(expResult)), is(false));
     result = repository.addContent(stream);
   }
   assertThat(result, is(notNullValue()));
   assertThat(HashUtil.bytesToHexString(result), is(expResult));
   assertThat(repository.hasContent(HashUtil.hexStringToByteArray(expResult)), is(true));
   assertTrue(expectedContent + " should have been created", Files.exists(expectedContent));
   assertTrue(parent + " should have been created", Files.exists(parent));
   repository.removeContent(new ContentReference("overlay.xhtml", expResult));
   assertFalse(repository.hasContent(HashUtil.hexStringToByteArray(expResult)));
   assertFalse(expectedContent + " should have been deleted", Files.exists(expectedContent));
   assertFalse(parent.toAbsolutePath() + " should have been deleted", Files.exists(parent));
   assertTrue(other + " should not have been deleted", Files.exists(other));
   assertTrue(grandparent + " should not have been deleted", Files.exists(grandparent));
   Path content = repository.getContent(result).getPhysicalFile().toPath();
   assertFalse(Files.exists(content));
 }
 /** Test of hasContent method, of class ContentRepository. */
 @Test
 public void testHasContent() throws Exception {
   String expResult = "0c40ffacd15b0f66d5081a93407d3ff5e3c65a71";
   try (InputStream stream = getResourceAsStream("overlay.xhtml")) {
     assertThat(repository.hasContent(HashUtil.hexStringToByteArray(expResult)), is(false));
     byte[] result = repository.addContent(stream);
     assertThat(result, is(notNullValue()));
     assertThat(HashUtil.bytesToHexString(result), is(expResult));
     assertThat(repository.hasContent(HashUtil.hexStringToByteArray(expResult)), is(true));
   }
 }