docstr: Test that checkpointer correctly calls save and restore based on time.
docstr_tok: ["Test","that","checkpointer","correctly","calls","save","and","restore","based","on","time","."]
code: def test_save_and_restore_time_based(self):
      """Test that checkpointer correctly calls save and restore based on time."""
  
      x = tf.Variable(0, dtype=tf.int32)
      directory = self.get_tempdir()
      checkpointer = tf2_savers.Checkpointer(
          objects_to_save={"x": x},
          time_delta_minutes=1.0,
          directory=directory,
      )
  
      with mock.patch.object(time, "time") as mock_time:
          mock_time.return_value = 0.0
          self.assertFalse(checkpointer.save())
  
          mock_time.return_value = 40.0
          self.assertFalse(checkpointer.save())
  
          mock_time.return_value = 70.0
          self.assertTrue(checkpointer.save())
      x.assign_add(1)
      checkpointer.restore()
      np.testing.assert_array_equal(x.numpy(), np.int32(0))
  
imports: import os
  import re
  import time
  from unittest import mock
  from acme import specs
  from acme.testing import test_utils
  from acme.tf import networks
  from acme.tf import savers
  from acme.tf import utils
  from acme.utils import paths
  import launchpad
  import numpy
  import sonnet
  import tensorflow
  import tree
  from absl.testing import absltest
label_desc: Use image node_id 3 for calling the CheckpointerTest obj's underlying member method code with example usage: obj.test_save_and_restore_time_based() without return types