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"""Unit tests for the range_trackers module."""

from __future__ import absolute_import

import logging
import unittest

from apache_beam.io.restriction_trackers import OffsetRange
from apache_beam.io.restriction_trackers import OffsetRestrictionTracker


class OffsetRangeTest(unittest.TestCase):

  def test_create(self):
    OffsetRange(0, 10)
    OffsetRange(10, 10)
    OffsetRange(10, 100)

    with self.assertRaises(ValueError):
      OffsetRange(10, 9)

  def test_split_respects_desired_num_splits(self):
    range = OffsetRange(10, 100)
    splits = list(range.split(desired_num_offsets_per_split=25))
    self.assertEqual(4, len(splits))
    self.assertIn(OffsetRange(10, 35), splits)
    self.assertIn(OffsetRange(35, 60), splits)
    self.assertIn(OffsetRange(60, 85), splits)
    self.assertIn(OffsetRange(85, 100), splits)

  def test_split_respects_min_num_splits(self):
    range = OffsetRange(10, 100)
    splits = list(range.split(desired_num_offsets_per_split=5,
                              min_num_offsets_per_split=25))
    self.assertEqual(3, len(splits))
    self.assertIn(OffsetRange(10, 35), splits)
    self.assertIn(OffsetRange(35, 60), splits)
    self.assertIn(OffsetRange(60, 100), splits)

  def test_split_no_small_split_at_end(self):
    range = OffsetRange(10, 90)
    splits = list(range.split(desired_num_offsets_per_split=25))
    self.assertEqual(3, len(splits))
    self.assertIn(OffsetRange(10, 35), splits)
    self.assertIn(OffsetRange(35, 60), splits)
    self.assertIn(OffsetRange(60, 90), splits)

  def test_split_at(self):
    range = OffsetRange(0, 10)
    cur, residual = range.split_at(5)
    self.assertEqual(cur, OffsetRange(0, 5))
    self.assertEqual(residual, OffsetRange(5, 10))


class OffsetRestrictionTrackerTest(unittest.TestCase):

  def test_try_claim(self):
    tracker = OffsetRestrictionTracker(OffsetRange(100, 200))
    self.assertEqual(OffsetRange(100, 200), tracker.current_restriction())
    self.assertTrue(tracker.try_claim(100))
    self.assertTrue(tracker.try_claim(150))
    self.assertTrue(tracker.try_claim(199))
    self.assertFalse(tracker.try_claim(200))

  def test_checkpoint_unstarted(self):
    tracker = OffsetRestrictionTracker(OffsetRange(100, 200))
    _, checkpoint = tracker.try_split(0)
    self.assertEqual(OffsetRange(100, 100), tracker.current_restriction())
    self.assertEqual(OffsetRange(100, 200), checkpoint)

  def test_checkpoint_just_started(self):
    tracker = OffsetRestrictionTracker(OffsetRange(100, 200))
    self.assertTrue(tracker.try_claim(100))
    _, checkpoint = tracker.try_split(0)
    self.assertEqual(OffsetRange(100, 101), tracker.current_restriction())
    self.assertEqual(OffsetRange(101, 200), checkpoint)

  def test_checkpoint_regular(self):
    tracker = OffsetRestrictionTracker(OffsetRange(100, 200))
    self.assertTrue(tracker.try_claim(105))
    self.assertTrue(tracker.try_claim(110))
    _, checkpoint = tracker.try_split(0)
    self.assertEqual(OffsetRange(100, 111), tracker.current_restriction())
    self.assertEqual(OffsetRange(111, 200), checkpoint)

  def test_checkpoint_claimed_last(self):
    tracker = OffsetRestrictionTracker(OffsetRange(100, 200))
    self.assertTrue(tracker.try_claim(105))
    self.assertTrue(tracker.try_claim(110))
    self.assertTrue(tracker.try_claim(199))
    checkpoint = tracker.try_split(0)
    self.assertEqual(OffsetRange(100, 200), tracker.current_restriction())
    self.assertEqual(None, checkpoint)

  def test_checkpoint_after_failed_claim(self):
    tracker = OffsetRestrictionTracker(OffsetRange(100, 200))
    self.assertTrue(tracker.try_claim(105))
    self.assertTrue(tracker.try_claim(110))
    self.assertTrue(tracker.try_claim(160))
    self.assertFalse(tracker.try_claim(240))

    _, checkpoint = tracker.try_split(0)
    self.assertTrue(OffsetRange(100, 161), tracker.current_restriction())
    self.assertTrue(OffsetRange(161, 200), checkpoint)

  def test_non_monotonic_claim(self):
    with self.assertRaises(ValueError):
      tracker = OffsetRestrictionTracker(OffsetRange(100, 200))
      self.assertTrue(tracker.try_claim(105))
      self.assertTrue(tracker.try_claim(110))
      self.assertTrue(tracker.try_claim(103))

  def test_claim_before_starting_range(self):
    with self.assertRaises(ValueError):
      tracker = OffsetRestrictionTracker(OffsetRange(100, 200))
      tracker.try_claim(90)

  def test_check_done_after_try_claim_past_end_of_range(self):
    tracker = OffsetRestrictionTracker(OffsetRange(100, 200))
    self.assertTrue(tracker.try_claim(150))
    self.assertTrue(tracker.try_claim(175))
    self.assertFalse(tracker.try_claim(220))
    tracker.check_done()

  def test_check_done_after_try_claim_past_end_of_range(self):
    tracker = OffsetRestrictionTracker(OffsetRange(100, 200))
    self.assertTrue(tracker.try_claim(150))
    self.assertTrue(tracker.try_claim(175))
    self.assertFalse(tracker.try_claim(200))
    tracker.check_done()

  def test_check_done_after_try_claim_right_before_end_of_range(self):
    tracker = OffsetRestrictionTracker(OffsetRange(100, 200))
    self.assertTrue(tracker.try_claim(150))
    self.assertTrue(tracker.try_claim(175))
    self.assertTrue(tracker.try_claim(199))
    tracker.check_done()

  def test_check_done_when_not_done(self):
    tracker = OffsetRestrictionTracker(OffsetRange(100, 200))
    self.assertTrue(tracker.try_claim(150))
    self.assertTrue(tracker.try_claim(175))

    with self.assertRaises(ValueError):
      tracker.check_done()

  def test_try_split(self):
    tracker = OffsetRestrictionTracker(OffsetRange(100, 200))
    tracker.try_claim(100)
    cur, residual = tracker.try_split(0.5)
    self.assertEqual(OffsetRange(100, 150), cur)
    self.assertEqual(OffsetRange(150, 200), residual)
    self.assertEqual(cur, tracker.current_restriction())


if __name__ == '__main__':
  logging.getLogger().setLevel(logging.INFO)
  unittest.main()
