public Path getRoot() {
        return root;
    }
@DisplayName("makes the root directory absolute if needed")
    @Test
    void rootIsAbsoluteDir() throws IOException {
        Path root = newTempDb();
        try {
            Path relative = root.getFileSystem().getPath("relative");
            Files.createDirectories(relative);
            FileSystemSnapshotDatabase db2 = new FileSystemSnapshotDatabase(relative,
                ArchiveNioSupports.combined());
            assertEquals(root.getFileSystem().getPath(".").toRealPath()
                .resolve(relative), db2.getRoot());
            Path absolute = root.resolve("absolute");
            Files.createDirectories(absolute);
            FileSystemSnapshotDatabase db3 = new FileSystemSnapshotDatabase(absolute,
                ArchiveNioSupports.combined());
            assertEquals(absolute, db3.getRoot());
        } finally {
            deleteTree(root);
        }
    }