ExponentialRetryAlgorithmTest.java

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package com.google.api.gax.retrying;

import static com.google.common.truth.Truth.assertThat;
import static org.junit.Assert.assertEquals;
import static org.junit.Assert.assertFalse;
import static org.junit.Assert.assertTrue;

import com.google.api.gax.core.FakeApiClock;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.junit.runners.JUnit4;
import org.threeten.bp.Duration;

@RunWith(JUnit4.class)
public class ExponentialRetryAlgorithmTest {
  private final FakeApiClock clock = new FakeApiClock(0L);
  private final RetrySettings retrySettings =
      RetrySettings.newBuilder()
          .setMaxAttempts(6)
          .setInitialRetryDelay(Duration.ofMillis(1L))
          .setRetryDelayMultiplier(2.0)
          .setMaxRetryDelay(Duration.ofMillis(8L))
          .setInitialRpcTimeout(Duration.ofMillis(1L))
          .setJittered(false)
          .setRpcTimeoutMultiplier(2.0)
          .setMaxRpcTimeout(Duration.ofMillis(8L))
          .setTotalTimeout(Duration.ofMillis(200L))
          .build();
  private final ExponentialRetryAlgorithm algorithm =
      new ExponentialRetryAlgorithm(retrySettings, clock);

  @Test
  public void testCreateFirstAttempt() {
    TimedAttemptSettings attempt = algorithm.createFirstAttempt();

    // Checking only the most core values, to not make this test too implementation specific.
    assertEquals(0, attempt.getAttemptCount());
    assertEquals(0, attempt.getOverallAttemptCount());
    assertEquals(Duration.ZERO, attempt.getRetryDelay());
    assertEquals(Duration.ZERO, attempt.getRandomizedRetryDelay());
    assertEquals(Duration.ofMillis(1L), attempt.getRpcTimeout());
    assertEquals(Duration.ZERO, attempt.getRetryDelay());
  }

  @Test
  public void testCreateNextAttempt() {
    TimedAttemptSettings firstAttempt = algorithm.createFirstAttempt();
    TimedAttemptSettings secondAttempt = algorithm.createNextAttempt(firstAttempt);

    // Checking only the most core values, to not make this test too implementation specific.
    assertEquals(1, secondAttempt.getAttemptCount());
    assertEquals(1, secondAttempt.getOverallAttemptCount());
    assertEquals(Duration.ofMillis(1L), secondAttempt.getRetryDelay());
    assertEquals(Duration.ofMillis(1L), secondAttempt.getRandomizedRetryDelay());
    assertEquals(Duration.ofMillis(2L), secondAttempt.getRpcTimeout());

    TimedAttemptSettings thirdAttempt = algorithm.createNextAttempt(secondAttempt);
    assertEquals(2, thirdAttempt.getAttemptCount());
    assertEquals(Duration.ofMillis(2L), thirdAttempt.getRetryDelay());
    assertEquals(Duration.ofMillis(2L), thirdAttempt.getRandomizedRetryDelay());
    assertEquals(Duration.ofMillis(4L), thirdAttempt.getRpcTimeout());
  }

  @Test
  public void testTruncateToTotalTimeout() {
    RetrySettings timeoutSettings =
        retrySettings
            .toBuilder()
            .setInitialRpcTimeout(Duration.ofSeconds(4L))
            .setMaxRpcTimeout(Duration.ofSeconds(4L))
            .setTotalTimeout(Duration.ofSeconds(4L))
            .build();
    ExponentialRetryAlgorithm timeoutAlg = new ExponentialRetryAlgorithm(timeoutSettings, clock);

    TimedAttemptSettings firstAttempt = timeoutAlg.createFirstAttempt();
    TimedAttemptSettings secondAttempt = timeoutAlg.createNextAttempt(firstAttempt);
    assertThat(firstAttempt.getRpcTimeout()).isGreaterThan(secondAttempt.getRpcTimeout());

    TimedAttemptSettings thirdAttempt = timeoutAlg.createNextAttempt(secondAttempt);
    assertThat(secondAttempt.getRpcTimeout()).isGreaterThan(thirdAttempt.getRpcTimeout());
  }

  @Test
  public void testShouldRetryTrue() {
    TimedAttemptSettings attempt = algorithm.createFirstAttempt();
    for (int i = 0; i < 2; i++) {
      attempt = algorithm.createNextAttempt(attempt);
    }

    assertTrue(algorithm.shouldRetry(attempt));
  }

  @Test
  public void testShouldRetryFalseOnMaxAttempts() {
    TimedAttemptSettings attempt = algorithm.createFirstAttempt();
    for (int i = 0; i < 6; i++) {
      assertTrue(algorithm.shouldRetry(attempt));
      attempt = algorithm.createNextAttempt(attempt);
    }

    assertFalse(algorithm.shouldRetry(attempt));
  }

  @Test
  public void testShouldRetryFalseOnMaxTimeout() {
    TimedAttemptSettings attempt = algorithm.createFirstAttempt();
    for (int i = 0; i < 4; i++) {
      assertTrue(algorithm.shouldRetry(attempt));
      attempt = algorithm.createNextAttempt(attempt);
      clock.incrementNanoTime(Duration.ofMillis(50L).toNanos());
    }

    assertFalse(algorithm.shouldRetry(attempt));
  }
}