/**
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you 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.
*/
package org.apache.hadoop.metrics2.util;
import org.junit.Test;
import static org.junit.Assert.*;
/**
* Test the running sample stat computation
*/
public class TestSampleStat {
private static final double EPSILON = 1e-42;
/**
* Some simple use cases
*/
@Test public void testSimple() {
SampleStat stat = new SampleStat();
assertEquals("num samples", 0, stat.numSamples());
assertEquals("mean", 0.0, stat.mean(), EPSILON);
assertEquals("variance", 0.0, stat.variance(), EPSILON);
assertEquals("stddev", 0.0, stat.stddev(), EPSILON);
assertEquals("min", SampleStat.MinMax.DEFAULT_MIN_VALUE, stat.min(), EPSILON);
assertEquals("max", SampleStat.MinMax.DEFAULT_MAX_VALUE, stat.max(), EPSILON);
stat.add(3);
assertEquals("num samples", 1L, stat.numSamples());
assertEquals("mean", 3.0, stat.mean(), EPSILON);
assertEquals("variance", 0.0, stat.variance(), EPSILON);
assertEquals("stddev", 0.0, stat.stddev(), EPSILON);
assertEquals("min", 3.0, stat.min(), EPSILON);
assertEquals("max", 3.0, stat.max(), EPSILON);
stat.add(2).add(1);
assertEquals("num samples", 3L, stat.numSamples());
assertEquals("mean", 2.0, stat.mean(), EPSILON);
assertEquals("variance", 1.0, stat.variance(), EPSILON);
assertEquals("stddev", 1.0, stat.stddev(), EPSILON);
assertEquals("min", 1.0, stat.min(), EPSILON);
assertEquals("max", 3.0, stat.max(), EPSILON);
stat.reset();
assertEquals("num samples", 0, stat.numSamples());
assertEquals("mean", 0.0, stat.mean(), EPSILON);
assertEquals("variance", 0.0, stat.variance(), EPSILON);
assertEquals("stddev", 0.0, stat.stddev(), EPSILON);
assertEquals("min", SampleStat.MinMax.DEFAULT_MIN_VALUE, stat.min(), EPSILON);
assertEquals("max", SampleStat.MinMax.DEFAULT_MAX_VALUE, stat.max(), EPSILON);
}
}