/**
* 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.mahout.cf.taste.impl.common;
import org.apache.mahout.cf.taste.impl.TasteTestCase;
import org.junit.Test;
public final class InvertedRunningAverageTest extends TasteTestCase {
@Test
public void testAverage() {
RunningAverage avg = new FullRunningAverage();
RunningAverage inverted = new InvertedRunningAverage(avg);
assertEquals(0, inverted.getCount());
avg.addDatum(1.0);
assertEquals(1, inverted.getCount());
assertEquals(-1.0, inverted.getAverage(), EPSILON);
avg.addDatum(2.0);
assertEquals(2, inverted.getCount());
assertEquals(-1.5, inverted.getAverage(), EPSILON);
}
@Test(expected = UnsupportedOperationException.class)
public void testUnsupported1() {
RunningAverage inverted = new InvertedRunningAverage(new FullRunningAverage());
inverted.addDatum(1.0);
}
@Test(expected = UnsupportedOperationException.class)
public void testUnsupported2() {
RunningAverage inverted = new InvertedRunningAverage(new FullRunningAverage());
inverted.changeDatum(1.0);
}
@Test(expected = UnsupportedOperationException.class)
public void testUnsupported3() {
RunningAverage inverted = new InvertedRunningAverage(new FullRunningAverage());
inverted.removeDatum(1.0);
}
@Test
public void testAverageAndStdDev() {
RunningAverageAndStdDev avg = new FullRunningAverageAndStdDev();
RunningAverageAndStdDev inverted = new InvertedRunningAverageAndStdDev(avg);
assertEquals(0, inverted.getCount());
avg.addDatum(1.0);
assertEquals(1, inverted.getCount());
assertEquals(-1.0, inverted.getAverage(), EPSILON);
avg.addDatum(2.0);
assertEquals(2, inverted.getCount());
assertEquals(-1.5, inverted.getAverage(), EPSILON);
assertEquals(Math.sqrt(2.0)/2.0, inverted.getStandardDeviation(), EPSILON);
}
@Test(expected = UnsupportedOperationException.class)
public void testAndStdDevUnsupported1() {
RunningAverage inverted = new InvertedRunningAverageAndStdDev(new FullRunningAverageAndStdDev());
inverted.addDatum(1.0);
}
@Test(expected = UnsupportedOperationException.class)
public void testAndStdDevUnsupported2() {
RunningAverage inverted = new InvertedRunningAverageAndStdDev(new FullRunningAverageAndStdDev());
inverted.changeDatum(1.0);
}
@Test(expected = UnsupportedOperationException.class)
public void testAndStdDevUnsupported3() {
RunningAverage inverted = new InvertedRunningAverageAndStdDev(new FullRunningAverageAndStdDev());
inverted.removeDatum(1.0);
}
}