core/src/test/java/io/grpc/internal/ExponentialBackoffPolicyTest.java

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package io.grpc.internal;

import static org.junit.Assert.assertEquals;
import static org.junit.Assert.assertNotNull;

import java.util.Random;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.junit.runners.JUnit4;

/**
 * Test for {@link ExponentialBackoffPolicy}.
 */
@RunWith(JUnit4.class)
public class ExponentialBackoffPolicyTest {
  private ExponentialBackoffPolicy policy = new ExponentialBackoffPolicy();
  private Random notRandom = new Random() {
    @Override
    public double nextDouble() {
      return .5;
    }
  };

  @Test
  public void maxDelayReached() {
    long maxBackoffMillis = 120 * 1000;
    policy.setMaxBackoffMillis(maxBackoffMillis)
        .setJitter(0)
        .setRandom(notRandom);
    for (int i = 0; i < 50; i++) {
      if (maxBackoffMillis == policy.nextBackoffMillis()) {
        return; // Success
      }
    }
    assertEquals("max delay not reached", maxBackoffMillis, policy.nextBackoffMillis());
  }

  @Test public void canProvide() {
    assertNotNull(new ExponentialBackoffPolicy.Provider().get());
  }
}