def test_train_hooks_exist_in_get_hooks_fn(self, create_gan_model_fn):
    model = create_gan_model_fn()
    loss = train.gan_loss(model)

    g_opt = get_sync_optimizer()
    d_opt = get_sync_optimizer()
    train_ops = train.gan_train_ops(
        model,
        loss,
        g_opt,
        d_opt,
        summarize_gradients=True,
        colocate_gradients_with_ops=True)

    sequential_train_hooks = train.get_sequential_train_hooks()(train_ops)
    self.assertLen(sequential_train_hooks, 4)
    sync_opts = [
        hook._sync_optimizer for hook in sequential_train_hooks if
        isinstance(hook, sync_replicas_optimizer._SyncReplicasOptimizerHook)]
    self.assertLen(sync_opts, 2)
    self.assertSetEqual(frozenset(sync_opts), frozenset((g_opt, d_opt)))

    joint_train_hooks = train.get_joint_train_hooks()(train_ops)
    self.assertLen(joint_train_hooks, 5)
    sync_opts = [
        hook._sync_optimizer for hook in joint_train_hooks if
        isinstance(hook, sync_replicas_optimizer._SyncReplicasOptimizerHook)]
    self.assertLen(sync_opts, 2)
    self.assertSetEqual(frozenset(sync_opts), frozenset((g_opt, d_opt)))

  def test_unused_update_ops(self, create_gan_model_fn, provide_update_ops):
    model = create_gan_model_fn()
    loss = train.gan_loss(model)

    # Add generator and discriminator update ops.
    with variable_scope.variable_scope(model.generator_scope):
      gen_update_count = variable_scope.get_variable('gen_count', initializer=0)
      gen_update_op = gen_update_count.assign_add(1)
      ops.add_to_collection(ops.GraphKeys.UPDATE_OPS, gen_update_op)
    with variable_scope.variable_scope(model.discriminator_scope):
      dis_update_count = variable_scope.get_variable('dis_count', initializer=0)
      dis_update_op = dis_update_count.assign_add(1)
      ops.add_to_collection(ops.GraphKeys.UPDATE_OPS, dis_update_op)

    # Add an update op outside the generator and discriminator scopes.
    if provide_update_ops:
      kwargs = {
          'update_ops': [
              constant_op.constant(1.0), gen_update_op, dis_update_op
          ]
      }
    else:
      ops.add_to_collection(ops.GraphKeys.UPDATE_OPS, constant_op.constant(1.0))
      kwargs = {}

    g_opt = gradient_descent.GradientDescentOptimizer(1.0)
    d_opt = gradient_descent.GradientDescentOptimizer(1.0)

    with self.assertRaisesRegexp(ValueError, 'There are unused update ops:'):
      train.gan_train_ops(
          model, loss, g_opt, d_opt, check_for_unused_update_ops=True, **kwargs)
    train_ops = train.gan_train_ops(
        model, loss, g_opt, d_opt, check_for_unused_update_ops=False, **kwargs)

    with self.test_session(use_gpu=True) as sess:
      sess.run(variables.global_variables_initializer())
      self.assertEqual(0, gen_update_count.eval())
      self.assertEqual(0, dis_update_count.eval())

      train_ops.generator_train_op.eval()
      self.assertEqual(1, gen_update_count.eval())
      self.assertEqual(0, dis_update_count.eval())

      train_ops.discriminator_train_op.eval()
      self.assertEqual(1, gen_update_count.eval())
      self.assertEqual(1, dis_update_count.eval())

  def test_sync_replicas(self, create_gan_model_fn, create_global_step):
    model = create_gan_model_fn()
    loss = train.gan_loss(model)
    num_trainable_vars = len(variables_lib.get_trainable_variables())

    if create_global_step:
      gstep = variable_scope.get_variable(
          'custom_gstep', dtype=dtypes.int32, initializer=0, trainable=False)
      ops.add_to_collection(ops.GraphKeys.GLOBAL_STEP, gstep)

    g_opt = get_sync_optimizer()
    d_opt = get_sync_optimizer()
    train_ops = train.gan_train_ops(
        model, loss, generator_optimizer=g_opt, discriminator_optimizer=d_opt)
    self.assertIsInstance(train_ops, namedtuples.GANTrainOps)
    # No new trainable variables should have been added.
    self.assertLen(variables_lib.get_trainable_variables(), num_trainable_vars)

    # Sync hooks should be populated in the GANTrainOps.
    self.assertLen(train_ops.train_hooks, 2)
    for hook in train_ops.train_hooks:
      self.assertIsInstance(
          hook, sync_replicas_optimizer._SyncReplicasOptimizerHook)
    sync_opts = [hook._sync_optimizer for hook in train_ops.train_hooks]
    self.assertSetEqual(frozenset(sync_opts), frozenset((g_opt, d_opt)))

    g_sync_init_op = g_opt.get_init_tokens_op(num_tokens=1)
    d_sync_init_op = d_opt.get_init_tokens_op(num_tokens=1)

    # Check that update op is run properly.
    global_step = training_util.get_or_create_global_step()
    with self.test_session(use_gpu=True) as sess:
      variables.global_variables_initializer().run()
      variables.local_variables_initializer().run()

      g_opt.chief_init_op.run()
      d_opt.chief_init_op.run()

      gstep_before = global_step.eval()

      # Start required queue runner for SyncReplicasOptimizer.
      coord = coordinator.Coordinator()
      g_threads = g_opt.get_chief_queue_runner().create_threads(sess, coord)
      d_threads = d_opt.get_chief_queue_runner().create_threads(sess, coord)

      g_sync_init_op.run()
      d_sync_init_op.run()

      train_ops.generator_train_op.eval()
      # Check that global step wasn't incremented.
      self.assertEqual(gstep_before, global_step.eval())

      train_ops.discriminator_train_op.eval()
      # Check that global step wasn't incremented.
      self.assertEqual(gstep_before, global_step.eval())

      coord.request_stop()
      coord.join(g_threads + d_threads)

  def _test_run_helper(self, create_gan_model_fn):
    random_seed.set_random_seed(1234)
    model = create_gan_model_fn()
    loss = train.gan_loss(model)

    g_opt = gradient_descent.GradientDescentOptimizer(1.0)
    d_opt = gradient_descent.GradientDescentOptimizer(1.0)
    train_ops = train.gan_train_ops(model, loss, g_opt, d_opt)

    final_step = train.gan_train(
        train_ops,
        logdir='',
        hooks=[basic_session_run_hooks.StopAtStepHook(num_steps=2)])
    self.assertTrue(np.isscalar(final_step))
    self.assertEqual(2, final_step)

  def _test_output_type_helper(self, create_gan_model_fn):
    model = create_gan_model_fn()
    loss = train.gan_loss(model)

    g_opt = gradient_descent.GradientDescentOptimizer(1.0)
    d_opt = gradient_descent.GradientDescentOptimizer(1.0)
    train_ops = train.gan_train_ops(
        model,
        loss,
        g_opt,
        d_opt,
        summarize_gradients=True,
        colocate_gradients_with_ops=True)

    self.assertTrue(isinstance(train_ops, namedtuples.GANTrainOps))

  def test_patchgan(self, create_gan_model_fn):
    """Ensure that patch-based discriminators work end-to-end."""
    random_seed.set_random_seed(1234)
    model = create_gan_model_fn()
    loss = train.gan_loss(model)

    g_opt = gradient_descent.GradientDescentOptimizer(1.0)
    d_opt = gradient_descent.GradientDescentOptimizer(1.0)
    train_ops = train.gan_train_ops(model, loss, g_opt, d_opt)

    final_step = train.gan_train(
        train_ops,
        logdir='',
        hooks=[basic_session_run_hooks.StopAtStepHook(num_steps=2)])
    self.assertTrue(np.isscalar(final_step))
    self.assertEqual(2, final_step)

  def test_output_type(self, create_gan_model_fn):
    model = create_gan_model_fn()
    loss = train.gan_loss(model)

    g_opt = gradient_descent.GradientDescentOptimizer(1.0)
    d_opt = gradient_descent.GradientDescentOptimizer(1.0)
    train_ops = train.gan_train_ops(
        model,
        loss,
        g_opt,
        d_opt,
        summarize_gradients=True,
        colocate_gradients_with_ops=True)

    self.assertIsInstance(train_ops, namedtuples.GANTrainOps)

    # Make sure there are no training hooks populated accidentally.
    self.assertEmpty(train_ops.train_hooks)

  def test_is_chief_in_train_hooks(self, is_chief):
    """Make sure is_chief is propagated correctly to sync hooks."""
    model = create_gan_model()
    loss = train.gan_loss(model)
    g_opt = get_sync_optimizer()
    d_opt = get_sync_optimizer()
    train_ops = train.gan_train_ops(
        model,
        loss,
        g_opt,
        d_opt,
        is_chief=is_chief,
        summarize_gradients=True,
        colocate_gradients_with_ops=True)

    self.assertLen(train_ops.train_hooks, 2)
    for hook in train_ops.train_hooks:
      self.assertIsInstance(
          hook, sync_replicas_optimizer._SyncReplicasOptimizerHook)
    is_chief_list = [hook._is_chief for hook in train_ops.train_hooks]
    self.assertListEqual(is_chief_list, [is_chief, is_chief])