# Copyright 2015 The TensorFlow Authors. All Rights Reserved.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#     http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
# ==============================================================================
"""Tests the graph freezing tool."""
from __future__ import absolute_import
from __future__ import division
from __future__ import print_function

import os

import tensorflow as tf

from tensorflow.python.framework import test_util
from tensorflow.python.tools import freeze_graph


class FreezeGraphTest(test_util.TensorFlowTestCase):

  def testFreezeGraph(self):

    checkpoint_prefix = os.path.join(self.get_temp_dir(), "saved_checkpoint")
    checkpoint_state_name = "checkpoint_state"
    input_graph_name = "input_graph.pb"
    output_graph_name = "output_graph.pb"

    # We'll create an input graph that has a single variable containing 1.0,
    # and that then multiplies it by 2.
    with tf.Graph().as_default():
      variable_node = tf.Variable(1.0, name="variable_node")
      output_node = tf.mul(variable_node, 2.0, name="output_node")
      sess = tf.Session()
      init = tf.initialize_all_variables()
      sess.run(init)
      output = sess.run(output_node)
      self.assertNear(2.0, output, 0.00001)
      saver = tf.train.Saver()
      saver.save(sess, checkpoint_prefix, global_step=0,
                 latest_filename=checkpoint_state_name)
      tf.train.write_graph(sess.graph.as_graph_def(), self.get_temp_dir(),
                           input_graph_name)

    # We save out the graph to disk, and then call the const conversion
    # routine.
    input_graph_path = os.path.join(self.get_temp_dir(), input_graph_name)
    input_saver_def_path = ""
    input_binary = False
    input_checkpoint_path = checkpoint_prefix + "-0"
    output_node_names = "output_node"
    restore_op_name = "save/restore_all"
    filename_tensor_name = "save/Const:0"
    output_graph_path = os.path.join(self.get_temp_dir(), output_graph_name)
    clear_devices = False

    freeze_graph.freeze_graph(input_graph_path, input_saver_def_path,
                              input_binary, input_checkpoint_path,
                              output_node_names, restore_op_name,
                              filename_tensor_name, output_graph_path,
                              clear_devices, "")

    # Now we make sure the variable is now a constant, and that the graph still
    # produces the expected result.
    with tf.Graph().as_default():
      output_graph_def = tf.GraphDef()
      with open(output_graph_path, "rb") as f:
        output_graph_def.ParseFromString(f.read())
        _ = tf.import_graph_def(output_graph_def, name="")

      self.assertEqual(4, len(output_graph_def.node))
      for node in output_graph_def.node:
        self.assertNotEqual("Variable", node.op)

      with tf.Session() as sess:
        output_node = sess.graph.get_tensor_by_name("output_node:0")
        output = sess.run(output_node)
        self.assertNear(2.0, output, 0.00001)

if __name__ == "__main__":
  tf.test.main()
