/*
* Copyright 2002-2014 the original author or authors.
*
* Licensed 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.springframework.util;
import org.junit.Rule;
import org.junit.Test;
import org.junit.rules.ExpectedException;
import org.springframework.util.backoff.BackOffExecution;
import org.springframework.util.backoff.ExponentialBackOff;
import static org.junit.Assert.*;
/**
*
* @author Stephane Nicoll
*/
public class ExponentialBackOffTests {
@Rule
public final ExpectedException thrown = ExpectedException.none();
@Test
public void defaultInstance() {
ExponentialBackOff backOff = new ExponentialBackOff();
BackOffExecution execution = backOff.start();
assertEquals(2000l, execution.nextBackOff());
assertEquals(3000l, execution.nextBackOff());
assertEquals(4500l, execution.nextBackOff());
}
@Test
public void simpleIncrease() {
ExponentialBackOff backOff = new ExponentialBackOff(100L, 2.0);
BackOffExecution execution = backOff.start();
assertEquals(100l, execution.nextBackOff());
assertEquals(200l, execution.nextBackOff());
assertEquals(400l, execution.nextBackOff());
assertEquals(800l, execution.nextBackOff());
}
@Test
public void fixedIncrease() {
ExponentialBackOff backOff = new ExponentialBackOff(100L, 1.0);
backOff.setMaxElapsedTime(300l);
BackOffExecution execution = backOff.start();
assertEquals(100l, execution.nextBackOff());
assertEquals(100l, execution.nextBackOff());
assertEquals(100l, execution.nextBackOff());
assertEquals(BackOffExecution.STOP, execution.nextBackOff());
}
@Test
public void maxIntervalReached() {
ExponentialBackOff backOff = new ExponentialBackOff(2000L, 2.0);
backOff.setMaxInterval(4000L);
BackOffExecution execution = backOff.start();
assertEquals(2000l, execution.nextBackOff());
assertEquals(4000l, execution.nextBackOff());
assertEquals(4000l, execution.nextBackOff()); // max reached
assertEquals(4000l, execution.nextBackOff());
}
@Test
public void maxAttemptsReached() {
ExponentialBackOff backOff = new ExponentialBackOff(2000L, 2.0);
backOff.setMaxElapsedTime(4000L);
BackOffExecution execution = backOff.start();
assertEquals(2000l, execution.nextBackOff());
assertEquals(4000l, execution.nextBackOff());
assertEquals(BackOffExecution.STOP, execution.nextBackOff()); // > 4 sec wait in total
}
@Test
public void startReturnDifferentInstances() {
ExponentialBackOff backOff = new ExponentialBackOff();
backOff.setInitialInterval(2000L);
backOff.setMultiplier(2.0);
backOff.setMaxElapsedTime(4000L);
BackOffExecution execution = backOff.start();
BackOffExecution execution2 = backOff.start();
assertEquals(2000l, execution.nextBackOff());
assertEquals(2000l, execution2.nextBackOff());
assertEquals(4000l, execution.nextBackOff());
assertEquals(4000l, execution2.nextBackOff());
assertEquals(BackOffExecution.STOP, execution.nextBackOff());
assertEquals(BackOffExecution.STOP, execution2.nextBackOff());
}
@Test
public void invalidInterval() {
ExponentialBackOff backOff = new ExponentialBackOff();
thrown.expect(IllegalArgumentException.class);
backOff.setMultiplier(0.9);
}
@Test
public void maxIntervalReachedImmediately() {
ExponentialBackOff backOff = new ExponentialBackOff(1000L, 2.0);
backOff.setMaxInterval(50L);
BackOffExecution execution = backOff.start();
assertEquals(50L, execution.nextBackOff());
assertEquals(50L, execution.nextBackOff());
}
@Test
public void toStringContent() {
ExponentialBackOff backOff = new ExponentialBackOff(2000L, 2.0);
BackOffExecution execution = backOff.start();
assertEquals("ExponentialBackOff{currentInterval=n/a, multiplier=2.0}", execution.toString());
execution.nextBackOff();
assertEquals("ExponentialBackOff{currentInterval=2000ms, multiplier=2.0}", execution.toString());
execution.nextBackOff();
assertEquals("ExponentialBackOff{currentInterval=4000ms, multiplier=2.0}", execution.toString());
}
}