# Copyright 2017 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 for `tf.data.experimental.shuffle_and_repeat()`."""
from __future__ import absolute_import
from __future__ import division
from __future__ import print_function

import numpy as np

from tensorflow.python.data.experimental.ops import shuffle_ops
from tensorflow.python.data.kernel_tests import test_base
from tensorflow.python.data.ops import dataset_ops
from tensorflow.python.framework import errors
from tensorflow.python.framework import ops
from tensorflow.python.platform import test


class ShuffleAndRepeatTest(test_base.DatasetTestBase):

  def _build_ds(self, seed, count=5, num_elements=20):
    return dataset_ops.Dataset.range(num_elements).apply(
        shuffle_ops.shuffle_and_repeat(buffer_size=5, count=count, seed=seed))

  def _gen_outputs(self, ds_fn, num_outputs, verify_exhausted=True):
    get_next = ds_fn().make_one_shot_iterator().get_next()
    outputs = []
    with self.cached_session() as sess:
      for _ in range(num_outputs):
        outputs.append(sess.run(get_next))
      if verify_exhausted:
        with self.assertRaises(errors.OutOfRangeError):
          sess.run(get_next)
    return outputs

  def testCorrectOutput(self):
    output = self._gen_outputs(lambda: self._build_ds(10), 100)
    self.assertSequenceEqual(
        sorted(output), sorted(
            np.array([range(20) for _ in range(5)]).flatten()))
    for i in range(5):
      self.assertSequenceEqual(sorted(output[i * 20:(i + 1) * 20]), range(20))

  def testReshuffling(self):
    # Check that the output orders of different epochs are indeed different.
    output = self._gen_outputs(lambda: self._build_ds(10), 100)
    for i in range(4):
      epoch1 = output[i * 20:(i + 1) * 20]
      epoch2 = output[(i + 1) * 20:(i + 2) * 20]
      self.assertNotEqual(epoch1, epoch2)

  def testSameOrderForSameSeeds(self):
    output1 = self._gen_outputs(lambda: self._build_ds(10), 100)
    output2 = self._gen_outputs(lambda: self._build_ds(10), 100)
    self.assertEqual(output1, output2)

  def testDifferentOrderForDifferentSeeds(self):
    output1 = self._gen_outputs(lambda: self._build_ds(10), 100)
    output2 = self._gen_outputs(lambda: self._build_ds(20), 100)
    self.assertNotEqual(output1, output2)
    self.assertEqual(sorted(output1), sorted(output2))

  def testCountNone(self):
    output1 = self._gen_outputs(
        lambda: self._build_ds(10, count=None), 100, verify_exhausted=False)
    output2 = self._gen_outputs(
        lambda: self._build_ds(20, count=None), 100, verify_exhausted=False)
    self.assertNotEqual(output1, output2)
    self.assertEqual(sorted(output1), sorted(output2))

  def testCountMinusOne(self):
    output1 = self._gen_outputs(
        lambda: self._build_ds(10, count=-1), 100, verify_exhausted=False)
    output2 = self._gen_outputs(
        lambda: self._build_ds(20, count=-1), 100, verify_exhausted=False)
    self.assertNotEqual(output1, output2)
    self.assertEqual(sorted(output1), sorted(output2))

  def testInfiniteOutputs(self):
    # Asserting the iterator is exhausted after producing 100 items should fail.
    with self.assertRaises(AssertionError):
      self._gen_outputs(lambda: self._build_ds(10, count=None), 100)
    with self.assertRaises(AssertionError):
      self._gen_outputs(lambda: self._build_ds(10, count=-1), 100)

  def testInfiniteEmpty(self):
    with self.assertRaises(errors.OutOfRangeError):
      self._gen_outputs(lambda: self._build_ds(10, count=None, num_elements=0),
                        100)
    with self.assertRaises(errors.OutOfRangeError):
      self._gen_outputs(lambda: self._build_ds(10, count=-1, num_elements=0),
                        100)

  def testLargeBufferSize(self):
    with ops.Graph().as_default() as g:
      ds = dataset_ops.Dataset.range(20).apply(
          shuffle_ops.shuffle_and_repeat(buffer_size=21))
      get_next_op = ds.make_one_shot_iterator().get_next()
      with self.session(graph=g) as sess:
        sess.run(get_next_op)


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