TruncatedBinaryBackoffTest.java

// =================================================================================================
// Copyright 2011 Twitter, Inc.
// -------------------------------------------------------------------------------------------------
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this work except in compliance with the License.
// You may obtain a copy of the License in the LICENSE file, or 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 com.twitter.common.util;

import com.twitter.common.quantity.Amount;
import com.twitter.common.quantity.Time;
import org.junit.Test;

import static org.junit.Assert.assertEquals;
import static org.junit.Assert.assertFalse;
import static org.junit.Assert.assertTrue;

/**
 * @author John Sirois
 */
public class TruncatedBinaryBackoffTest {
  @Test(expected = NullPointerException.class)
  public void testNullInitialBackoffRejected() {
    new TruncatedBinaryBackoff(null, Amount.of(1L, Time.SECONDS));
  }

  @Test(expected = IllegalArgumentException.class)
  public void testZeroInitialBackoffRejected() {
    new TruncatedBinaryBackoff(Amount.of(0L, Time.SECONDS), Amount.of(1L, Time.SECONDS));
  }

  @Test(expected = IllegalArgumentException.class)
  public void testNegativeInitialBackoffRejected() {
    new TruncatedBinaryBackoff(Amount.of(-1L, Time.SECONDS), Amount.of(1L, Time.SECONDS));
  }

  @Test(expected = NullPointerException.class)
  public void testNullMaximumBackoffRejected() {
    new TruncatedBinaryBackoff(Amount.of(1L, Time.SECONDS), null);
  }

  @Test(expected = IllegalArgumentException.class)
  public void testMaximumBackoffLessThanInitialBackoffRejected() {
    new TruncatedBinaryBackoff(Amount.of(2L, Time.SECONDS), Amount.of(1L, Time.SECONDS));
  }

  @Test
  public void testCalculateBackoffMs() {
    TruncatedBinaryBackoff backoff =
        new TruncatedBinaryBackoff(Amount.of(1L, Time.MILLISECONDS),
            Amount.of(6L, Time.MILLISECONDS));

    try {
      backoff.calculateBackoffMs(-1L);
    } catch (IllegalArgumentException e) {
      // expected
    }

    assertEquals(1, backoff.calculateBackoffMs(0));
    assertEquals(2, backoff.calculateBackoffMs(1));
    assertEquals(4, backoff.calculateBackoffMs(2));
    assertEquals(6, backoff.calculateBackoffMs(4));
    assertEquals(6, backoff.calculateBackoffMs(8));
  }

  @Test
  public void testCalculateBackoffStop() {
    TruncatedBinaryBackoff backoff =
        new TruncatedBinaryBackoff(Amount.of(1L, Time.MILLISECONDS),
            Amount.of(6L, Time.MILLISECONDS), true);

    assertTrue(backoff.shouldContinue());
    assertEquals(1, backoff.calculateBackoffMs(0));
    assertTrue(backoff.shouldContinue());
    assertEquals(2, backoff.calculateBackoffMs(1));
    assertTrue(backoff.shouldContinue());
    assertEquals(4, backoff.calculateBackoffMs(2));
    assertTrue(backoff.shouldContinue());
    assertEquals(6, backoff.calculateBackoffMs(4));
    assertFalse(backoff.shouldContinue());
    assertEquals(6, backoff.calculateBackoffMs(8));
    assertFalse(backoff.shouldContinue());
  }
}