# 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.Dataset.skip()`."""
from __future__ import absolute_import
from __future__ import division
from __future__ import print_function

import numpy as np

from tensorflow.python.data.kernel_tests import test_base
from tensorflow.python.data.ops import dataset_ops
from tensorflow.python.framework import test_util
from tensorflow.python.platform import test


@test_util.run_all_in_graph_and_eager_modes
class SkipTest(test_base.DatasetTestBase):

  def testSkipTensorDataset(self):
    components = (np.arange(10),)

    def do_test(count):
      dataset = dataset_ops.Dataset.from_tensor_slices(components).skip(count)
      self.assertEqual(
          [c.shape[1:] for c in components],
          [shape for shape in dataset_ops.get_legacy_output_shapes(dataset)])
      start_range = min(count, 10) if count != -1 else 10
      self.assertDatasetProduces(
          dataset,
          [tuple(components[0][i:i + 1]) for i in range(start_range, 10)])

    # Skip fewer than input size, we should skip
    # the first 4 elements and then read the rest.
    do_test(4)

    # Skip more than input size: get nothing.
    do_test(25)

    # Skip exactly input size.
    do_test(10)

    # Set -1 for 'count': skip the entire dataset.
    do_test(-1)

    # Skip nothing
    do_test(0)



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