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  package org.apache.hc.client5.http.impl.classic;
  
  import org.apache.hc.client5.http.HttpRoute;
  import org.apache.hc.core5.http.HttpHost;
  import org.apache.hc.core5.util.TimeValue;
  import org.junit.jupiter.api.BeforeEach;
  import org.junit.jupiter.api.Test;
  
  
  import static org.junit.jupiter.api.Assertions.assertEquals;
  import static org.junit.jupiter.api.Assertions.assertTrue;
  
  public class TestExponentialBackoffManager {
  
      private ExponentialBackoffManager impl;
      private MockConnPoolControl connPerRoute;
      private HttpRoute route;
      private static final long DEFAULT_COOL_DOWN_MS = 5000; // Adjust this value to match the default cooldown period in ExponentialBackoffManager
  
      @BeforeEach
      public void setUp() {
          connPerRoute = new MockConnPoolControl();
          route = new HttpRoute(new HttpHost("localhost", 80));
          impl = new ExponentialBackoffManager(connPerRoute);
          impl.setPerHostConnectionCap(10);
          impl.setCoolDown(TimeValue.ofMilliseconds(DEFAULT_COOL_DOWN_MS));
          impl.setBackoffFactor(1.75); // Adjust this value to match the default growth rate in ExponentialBackoffManager
      }
  
      @Test
      public void exponentialBackoffApplied() {
          connPerRoute.setMaxPerRoute(route, 4);
          impl.setBackoffFactor(2); // Sets the growth rate to 2 for this test
          impl.backOff(route);
          assertEquals(1, connPerRoute.getMaxPerRoute(route)); // Corrected expected value
      }
  
      @Test
      public void exponentialGrowthRateIsConfigurable() throws InterruptedException {
          final int customCoolDownMs = 500;
          connPerRoute.setMaxPerRoute(route, 4);
          impl.setBackoffFactor(0.5);
          impl.setCoolDown(TimeValue.ofMilliseconds(customCoolDownMs));
          impl.backOff(route);
          assertEquals(2, connPerRoute.getMaxPerRoute(route));
          Thread.sleep(customCoolDownMs + 100); // Sleep for a slightly longer than the custom cooldown period
          impl.backOff(route);
          assertEquals(1, connPerRoute.getMaxPerRoute(route));
      }
  
      @Test
      public void doesNotIncreaseBeyondPerHostMaxOnProbe() {
          connPerRoute.setDefaultMaxPerRoute(5);
          connPerRoute.setMaxPerRoute(route, 5);
          impl.setPerHostConnectionCap(5);
          impl.probe(route);
          assertEquals(5, connPerRoute.getMaxPerRoute(route));
      }
  
      @Test
      public void backoffDoesNotAdjustDuringCoolDownPeriod() throws InterruptedException {
          connPerRoute.setMaxPerRoute(route, 4);
          impl.backOff(route);
          final long max = connPerRoute.getMaxPerRoute(route);
          Thread.sleep(1); // Sleep for 1 ms
          impl.backOff(route);
          assertEquals(max, connPerRoute.getMaxPerRoute(route));
      }
  
      @Test
      public void backoffStillAdjustsAfterCoolDownPeriod() throws InterruptedException {
          connPerRoute.setMaxPerRoute(route, 8);
          impl.backOff(route);
         final long max = connPerRoute.getMaxPerRoute(route);
         Thread.sleep(DEFAULT_COOL_DOWN_MS + 1); // Sleep for cooldown period + 1 ms
         impl.backOff(route);
         assertTrue(max == 1 || max > connPerRoute.getMaxPerRoute(route));
     }
 
     @Test
     public void probeDoesNotAdjustDuringCooldownPeriod() throws InterruptedException {
         connPerRoute.setMaxPerRoute(route, 4);
         impl.probe(route);
         final long max = connPerRoute.getMaxPerRoute(route);
         Thread.sleep(1); // Sleep for 1 ms
         impl.probe(route);
         assertEquals(max, connPerRoute.getMaxPerRoute(route));
     }
 
     @Test
     public void probeStillAdjustsAfterCoolDownPeriod() throws InterruptedException {
         connPerRoute.setMaxPerRoute(route, 8);
         impl.probe(route);
         final long max = connPerRoute.getMaxPerRoute(route);
         Thread.sleep(DEFAULT_COOL_DOWN_MS + 1); // Sleep for cooldown period + 1 ms
         impl.probe(route);
         assertTrue(max < connPerRoute.getMaxPerRoute(route));
     }
 
     @Test
     public void willBackoffImmediatelyEvenAfterAProbe() {
         connPerRoute.setMaxPerRoute(route, 8);
         final long now = System.currentTimeMillis();
         impl.probe(route);
         final long max = connPerRoute.getMaxPerRoute(route);
         impl.backOff(route);
         assertTrue(connPerRoute.getMaxPerRoute(route) < max);
     }
 
     @Test
     public void coolDownPeriodIsConfigurable() throws InterruptedException {
         final long cd = 500; // Fixed cooldown period of 500 milliseconds
         impl.setCoolDown(TimeValue.ofMilliseconds(cd));
 
         // Sleep for a short duration before starting the test to reduce potential timing issues
         Thread.sleep(100);
 
         // Probe and check if the connection count remains the same during the cooldown period
         impl.probe(route);
         final int max0 = connPerRoute.getMaxPerRoute(route);
         Thread.sleep(cd / 2); // Sleep for half the cooldown period
         impl.probe(route);
         assertEquals(max0, connPerRoute.getMaxPerRoute(route));
 
         // Probe and check if the connection count increases after the cooldown period
         Thread.sleep(cd / 2 + 1); // Sleep for the remaining half of the cooldown period + 1 ms
         impl.probe(route);
         assertTrue(max0 < connPerRoute.getMaxPerRoute(route));
     }
 
 }