| # Copyright 2014 The Chromium Authors. All rights reserved. |
| # Use of this source code is governed by a BSD-style license that can be |
| # found in the LICENSE file. |
| |
| import math |
| import unittest |
| |
| import math_utils |
| |
| |
| class MathUtilsTest(unittest.TestCase): |
| """Tests for mathematical utility functions.""" |
| |
| def testTruncatedMeanRaisesError(self): |
| """TruncatedMean should raise an error when passed an empty list.""" |
| with self.assertRaises(TypeError): |
| math_utils.TruncatedMean([], 0) |
| |
| def testMeanSingleNum(self): |
| """Tests the Mean function with a single number.""" |
| self.assertEqual(3.0, math_utils.Mean([3])) |
| |
| def testMeanShortList(self): |
| """Tests the Mean function with a short list.""" |
| self.assertEqual(0.5, math_utils.Mean([-3, 0, 1, 4])) |
| |
| def testMeanCompareAlternateImplementation(self): |
| """Tests Mean by comparing against an alternate implementation.""" |
| def AlternateMeanFunction(values): |
| """Simple arithmetic mean function.""" |
| return sum(values) / float(len(values)) |
| test_values_lists = [[1], [5, 6.5, 1.2, 3], [-3, 0, 1, 4], |
| [-3, -1, 0.12, 0.752, 3.33, 8, 16, 32, 439]] |
| for values in test_values_lists: |
| self.assertEqual( |
| AlternateMeanFunction(values), |
| math_utils.Mean(values)) |
| |
| def testRelativeChange(self): |
| """Tests the common cases for calculating relative change.""" |
| # The change is relative to the first value, regardless of which is bigger. |
| self.assertEqual(0.5, math_utils.RelativeChange(1.0, 1.5)) |
| self.assertEqual(0.5, math_utils.RelativeChange(2.0, 1.0)) |
| |
| def testRelativeChangeFromZero(self): |
| """Tests what happens when relative change from zero is calculated.""" |
| # If the first number is zero, then the result is not a number. |
| self.assertEqual(0, math_utils.RelativeChange(0, 0)) |
| self.assertTrue( |
| math.isnan(math_utils.RelativeChange(0, 1))) |
| self.assertTrue( |
| math.isnan(math_utils.RelativeChange(0, -1))) |
| |
| def testRelativeChangeWithNegatives(self): |
| """Tests that relative change given is always positive.""" |
| self.assertEqual(3.0, math_utils.RelativeChange(-1, 2)) |
| self.assertEqual(3.0, math_utils.RelativeChange(1, -2)) |
| self.assertEqual(1.0, math_utils.RelativeChange(-1, -2)) |
| |
| |
| if __name__ == '__main__': |
| unittest.main() |