DecorrelatedJitterDelayTest.java

package com.lambdaworks.redis.resource;

import static org.assertj.core.api.Assertions.assertThat;

import java.util.concurrent.TimeUnit;

import org.junit.Test;

/**
 * @author Jongyeol Choi
 */
public class DecorrelatedJitterDelayTest {

    @Test(expected = IllegalArgumentException.class)
    public void shouldNotCreateIfLowerBoundIsNegative() throws Exception {
        Delay.decorrelatedJitter(-1, 100, 0, TimeUnit.MILLISECONDS);
    }

    @Test(expected = IllegalArgumentException.class)
    public void shouldNotCreateIfLowerBoundIsSameAsUpperBound() throws Exception {
        Delay.decorrelatedJitter(100, 100, 1, TimeUnit.MILLISECONDS);
    }

    @Test
    public void negativeAttemptShouldReturnZero() throws Exception {

        Delay delay = Delay.decorrelatedJitter().get();

        assertThat(delay.createDelay(-1)).isEqualTo(0);
    }

    @Test
    public void zeroShouldReturnZero() throws Exception {

        Delay delay = Delay.decorrelatedJitter().get();

        assertThat(delay.createDelay(0)).isEqualTo(0);
    }

    @Test
    public void testDefaultDelays() throws Exception {

        Delay delay = Delay.decorrelatedJitter().get();

        assertThat(delay.getTimeUnit()).isEqualTo(TimeUnit.MILLISECONDS);

        for (int i = 0; i < 1000; i++) {
            assertThat(delay.createDelay(1)).isBetween(0L, 1L);
            assertThat(delay.createDelay(2)).isBetween(0L, 3L);
            assertThat(delay.createDelay(3)).isBetween(0L, 9L);
            assertThat(delay.createDelay(4)).isBetween(0L, 27L);
            assertThat(delay.createDelay(5)).isBetween(0L, 81L);
            assertThat(delay.createDelay(6)).isBetween(0L, 243L);
            assertThat(delay.createDelay(7)).isBetween(0L, 729L);
            assertThat(delay.createDelay(8)).isBetween(0L, 2187L);
            assertThat(delay.createDelay(9)).isBetween(0L, 6561L);
            assertThat(delay.createDelay(10)).isBetween(0L, 19683L);
            assertThat(delay.createDelay(11)).isBetween(0L, 30000L);
            assertThat(delay.createDelay(Integer.MAX_VALUE)).isBetween(0L, 30000L);
        }
    }
}