1#!/usr/bin/env python
2# Copyright 2009 Google Inc. All Rights Reserved.
3#
4# Licensed under the Apache License, Version 2.0 (the "License");
5# you may not use this file except in compliance with the License.
6# You may obtain a copy of the License at
7#
8#      http://www.apache.org/licenses/LICENSE-2.0
9#
10# Unless required by applicable law or agreed to in writing, software
11# distributed under the License is distributed on an "AS IS" BASIS,
12# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13# See the License for the specific language governing permissions and
14# limitations under the License.
15
16"""Tests for the selector module."""
17
18__author__ = 'tstromberg@google.com (Thomas Stromberg)'
19
20import selectors
21import unittest
22
23
24
25class SelectorsTest(unittest.TestCase):
26  def testMaxRepeatCount(self):
27    self.assertEquals(selectors.MaxRepeatCount(range(1,10), 5),
28                      selectors.MAX_REPEAT)
29    self.assertEquals(selectors.MaxRepeatCount(range(1,10), 50),
30                      2**32)
31
32  def testRandomSelect(self):
33    elements = range(10)
34    result = selectors.RandomSelect(elements, 10)
35    self.assertEquals(len(result), 10)
36    self.assertNotEquals(result, range(10))
37
38  def testRandomSelectConstrained(self):
39    elements = range(5)
40    result = selectors.RandomSelect(elements, 10)
41    self.assertEquals(len(result), 10)
42    ones = [x for x in result if x == 1]
43    twos = [x for x in result if x == 2]
44    self.assertTrue(len(ones) <= selectors.MAX_REPEAT)
45    self.assertTrue(len(twos) <= selectors.MAX_REPEAT)
46
47  def testRandomSelectVeryConstrained(self):
48    """Test to make sure we don't infinite loop if count > len(elements)*3"""
49    elements = range(2)
50    result = selectors.RandomSelect(elements, 20)
51    self.assertEquals(len(result), 20)
52    ones = [x for x in result if x == 1]
53    twos = [x for x in result if x == 2]
54    self.assertTrue(ones > selectors.MAX_REPEAT)
55    self.assertTrue(twos > selectors.MAX_REPEAT)
56
57  def testWeightedDistribution(self):
58    """Ensure that a weighted distribution is indeed weighted."""
59    elements = range(20)
60    result = selectors.WeightedDistribution(elements, 10)
61    self.assertEquals(len(result), 10)
62    zeros = [x for x in result if x == 0]
63    ones = [x for x in result if x == 1]
64    low = [x for x in result if x < 3]
65    mid = [x for x in result if x > 7 and x < 13]
66    high = [x for x in result if x > 17]
67    self.assertTrue(len(zeros) <= selectors.MAX_REPEAT)
68    self.assertTrue(len(ones) <= selectors.MAX_REPEAT)
69    self.assertTrue(len(low) >= 3)
70    self.assertTrue(len(mid) <= 3)
71    self.assertTrue(len(high) <= 2)
72
73  def testChuckSelect(self):
74    elements = range(10000)
75    result = selectors.ChunkSelect(elements, 5)
76    self.assertEquals(len(result), 5)
77    # Make sure our segment is a subset
78    self.assertTrue(set(result).issubset(set(elements)))
79
80    # Make sure our segment is contiguous
81    self.assertEquals(result, range(result[0], result[0]+5))
82
83
84    result2 = selectors.ChunkSelect(elements, 5)
85    self.assertEquals(len(result), 5)
86    self.assertNotEquals(result, result2)
87
88
89  def testChunkSelectConstrained(self):
90    """Make sure we aren't inventing bogus data."""
91    elements = range(20)
92    result = selectors.ChunkSelect(elements, 25)
93    self.assertEquals(len(result), 20)
94    self.assertEquals(elements, result)
95
96
97
98if __name__ == '__main__':
99  unittest.main()
100