| /* |
| * Copyright (C) 2019, Matthias Sohn <matthias.sohn@sap.com> and others |
| * |
| * This program and the accompanying materials are made available under the |
| * terms of the Eclipse Distribution License v. 1.0 which is available at |
| * https://www.eclipse.org/org/documents/edl-v10.php. |
| * |
| * SPDX-License-Identifier: BSD-3-Clause |
| */ |
| package org.eclipse.jgit.util; |
| |
| import static org.junit.Assert.assertEquals; |
| import static org.junit.Assert.assertTrue; |
| |
| import org.junit.Test; |
| |
| public class StatsTest { |
| @Test |
| public void testStatsTrivial() { |
| Stats s = new Stats(); |
| s.add(1); |
| s.add(1); |
| s.add(1); |
| assertEquals(3, s.count()); |
| assertEquals(1.0, s.min(), 1E-6); |
| assertEquals(1.0, s.max(), 1E-6); |
| assertEquals(1.0, s.avg(), 1E-6); |
| assertEquals(0.0, s.var(), 1E-6); |
| assertEquals(0.0, s.stddev(), 1E-6); |
| } |
| |
| @Test |
| public void testStats() { |
| Stats s = new Stats(); |
| s.add(1); |
| s.add(2); |
| s.add(3); |
| s.add(4); |
| assertEquals(4, s.count()); |
| assertEquals(1.0, s.min(), 1E-6); |
| assertEquals(4.0, s.max(), 1E-6); |
| assertEquals(2.5, s.avg(), 1E-6); |
| assertEquals(1.666667, s.var(), 1E-6); |
| assertEquals(1.290994, s.stddev(), 1E-6); |
| } |
| |
| @Test |
| /** |
| * see |
| * https://en.wikipedia.org/wiki/Algorithms_for_calculating_variance#Example |
| */ |
| public void testStatsCancellationExample1() { |
| Stats s = new Stats(); |
| s.add(1E8 + 4); |
| s.add(1E8 + 7); |
| s.add(1E8 + 13); |
| s.add(1E8 + 16); |
| assertEquals(4, s.count()); |
| assertEquals(1E8 + 4, s.min(), 1E-6); |
| assertEquals(1E8 + 16, s.max(), 1E-6); |
| assertEquals(1E8 + 10, s.avg(), 1E-6); |
| assertEquals(30, s.var(), 1E-6); |
| assertEquals(5.477226, s.stddev(), 1E-6); |
| } |
| |
| @Test |
| /** |
| * see |
| * https://en.wikipedia.org/wiki/Algorithms_for_calculating_variance#Example |
| */ |
| public void testStatsCancellationExample2() { |
| Stats s = new Stats(); |
| s.add(1E9 + 4); |
| s.add(1E9 + 7); |
| s.add(1E9 + 13); |
| s.add(1E9 + 16); |
| assertEquals(4, s.count()); |
| assertEquals(1E9 + 4, s.min(), 1E-6); |
| assertEquals(1E9 + 16, s.max(), 1E-6); |
| assertEquals(1E9 + 10, s.avg(), 1E-6); |
| assertEquals(30, s.var(), 1E-6); |
| assertEquals(5.477226, s.stddev(), 1E-6); |
| } |
| |
| @Test |
| public void testNoValues() { |
| Stats s = new Stats(); |
| assertTrue(Double.isNaN(s.var())); |
| assertTrue(Double.isNaN(s.stddev())); |
| assertTrue(Double.isNaN(s.avg())); |
| assertTrue(Double.isNaN(s.min())); |
| assertTrue(Double.isNaN(s.max())); |
| s.add(42.3); |
| assertTrue(Double.isNaN(s.var())); |
| assertTrue(Double.isNaN(s.stddev())); |
| assertEquals(42.3, s.avg(), 1E-6); |
| assertEquals(42.3, s.max(), 1E-6); |
| assertEquals(42.3, s.min(), 1E-6); |
| s.add(42.3); |
| assertEquals(0, s.var(), 1E-6); |
| assertEquals(0, s.stddev(), 1E-6); |
| } |
| } |