code: def test_update(self, tmp_dir, dvc, remote_worktree):
      (foo_stage,) = tmp_dir.dvc_gen("foo", "foo")
      (data_dir_stage,) = tmp_dir.dvc_gen(
          {
              "data_dir": {
                  "data_sub_dir": {"data_sub": "data_sub"},
                  "data": "data",
                  "empty": "",
              }
          }
      )
      dvc.push()
      orig_foo = foo_stage.reload().outs[0]
      orig_data_dir = data_dir_stage.reload().outs[0]
      (remote_worktree / "foo").write_text("bar")
      (remote_worktree / "data_dir" / "data").write_text("modified")
      (remote_worktree / "data_dir" / "new_data").write_text("new data")
  
      dvc.update(
          [str(tmp_dir / "foo.dvc"), str(tmp_dir / "data_dir.dvc")]
      )
      updated_foo = foo_stage.reload().outs[0]
      updated_data_dir = data_dir_stage.reload().outs[0]
  
      assert updated_foo.meta.version_id
      assert updated_foo.meta.version_id != orig_foo.meta.version_id
      updated_data_dir = data_dir_stage.reload().outs[0]
      orig_tree = orig_data_dir.get_obj()
      updated_tree = Tree.from_list(
          updated_data_dir.files, hash_name="md5"
      )
      assert orig_tree.get(
          ("data_sub_dir", "data_sub")
      ) == updated_tree.get(("data_sub_dir", "data_sub"))
      orig_meta, _ = orig_tree.get(("data",))
      updated_meta, _ = updated_tree.get(("data",))
      assert orig_meta.version_id
      assert updated_meta.version_id
      assert orig_meta.version_id != updated_meta.version_id
      meta, hash_info = updated_tree.get(("new_data",))
      assert meta
      assert hash_info
  
      assert (tmp_dir / "foo").read_text() == "bar"
      assert (tmp_dir / "data_dir" / "data").read_text() == "modified"
      assert (
          tmp_dir / "data_dir" / "new_data"
      ).read_text() == "new data"
  
      remove(dvc.cache.local.path)
      remove(tmp_dir / "foo")
      remove(tmp_dir / "data_dir")
      dvc.pull()
      assert (tmp_dir / "foo").read_text() == "bar"
      assert (tmp_dir / "data_dir" / "data").read_text() == "modified"
      assert (
          tmp_dir / "data_dir" / "new_data"
      ).read_text() == "new data"
  
file_path: dvc/dvc/testing/remote_tests.py
imports: import os
  import shutil
  import pytest
  from dvc.stage.cache import RunCacheNotSupported
  from dvc.utils.fs import remove
  from dvc_data.hashfile.tree import Tree
label_desc: Use image node_id 4 for calling the TestRemoteWorktree obj's underlying member method code with example usage: obj.test_update(tmp_dir, dvc, remote_worktree) without return types