docs: public static void containsAll(final Path expected, final Path actual) throws IOException {
  		final Assertion<Path> exists = existsIn(expected, actual);
  		if(Files.exists(expected)) {
  			walkFileTree(expected, new SimpleFileVisitor<Path>() {
  				@Override
  				public FileVisitResult visitFile(final Path file, final BasicFileAttributes attrs) throws IOException {
  					assertThat(file, exists);
  					return super.visitFile(file, attrs);
  				}
  			});
  		}
  	}