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  package org.apache.hc.client5.http.impl.classic;
  
  
  import static org.junit.jupiter.api.Assertions.assertEquals;
  import static org.junit.jupiter.api.Assertions.assertTrue;
  
  import java.time.Instant;
  import java.util.Map;
  
  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;
  
  class TestLinearBackoffManager {
  
      private LinearBackoffManager impl;
      private MockConnPoolControl connPerRoute;
      private HttpRoute route;
      private static final long DEFAULT_COOL_DOWN_MS = 10;
  
      @BeforeEach
      void setUp() {
          connPerRoute = new MockConnPoolControl();
          route = new HttpRoute(new HttpHost("localhost", 80));
          impl = new LinearBackoffManager(connPerRoute);
          impl.setCoolDown(TimeValue.ofMilliseconds(DEFAULT_COOL_DOWN_MS));
      }
  
      @Test
      void incrementsConnectionsOnBackoff() {
          final LinearBackoffManager impl = new LinearBackoffManager(connPerRoute);
          impl.setCoolDown(TimeValue.ofMilliseconds(DEFAULT_COOL_DOWN_MS)); // Set the cool-down period
          connPerRoute.setMaxPerRoute(route, 4);
          impl.backOff(route);
          assertEquals(5, connPerRoute.getMaxPerRoute(route));
      }
  
      @Test
      void decrementsConnectionsOnProbe() {
          connPerRoute.setMaxPerRoute(route, 4);
          impl.probe(route);
          assertEquals(3, connPerRoute.getMaxPerRoute(route));
      }
  
      @Test
      void backoffDoesNotAdjustDuringCoolDownPeriod() {
          // Arrange
          connPerRoute.setMaxPerRoute(route, 4);
          impl.backOff(route);
          final long max = connPerRoute.getMaxPerRoute(route);
  
          // Manipulate lastRouteBackoffs to simulate that not enough time has passed for the cooldown period
          final Map<HttpRoute, Instant> lastRouteBackoffs = impl.getLastRouteBackoffs();
          lastRouteBackoffs.put(route, Instant.now().minusMillis(DEFAULT_COOL_DOWN_MS - 1));
  
          // Act
          impl.backOff(route);
  
          // Assert
          assertEquals(max, connPerRoute.getMaxPerRoute(route));
      }
      @Test
      void backoffStillAdjustsAfterCoolDownPeriod() {
          // Arrange
          final LinearBackoffManager impl = new LinearBackoffManager(connPerRoute);
          impl.setCoolDown(TimeValue.ofMilliseconds(DEFAULT_COOL_DOWN_MS)); // Set the cool-down period
          connPerRoute.setMaxPerRoute(route, 4);
          impl.backOff(route);
          final int max1 = connPerRoute.getMaxPerRoute(route);
  
          // Manipulate lastRouteBackoffs to simulate that enough time has passed for the cooldown period
         final Map<HttpRoute, Instant> lastRouteBackoffs = impl.getLastRouteBackoffs();
         lastRouteBackoffs.put(route, Instant.now().minusMillis(DEFAULT_COOL_DOWN_MS + 1));
 
         // Act
         impl.backOff(route);
         final int max2 = connPerRoute.getMaxPerRoute(route);
 
         // Assert
         assertTrue(max2 > max1);
     }
 
     @Test
     void probeDoesNotAdjustDuringCooldownPeriod() {
         // Arrange
         connPerRoute.setMaxPerRoute(route, 4);
         impl.probe(route);
         final long max = connPerRoute.getMaxPerRoute(route);
 
         // Manipulate lastRouteProbes to simulate that not enough time has passed for the cooldown period
         final Map<HttpRoute, Instant> lastRouteProbes = impl.getLastRouteProbes();
         lastRouteProbes.put(route, Instant.now());
 
         // Act
         impl.probe(route);
 
         // Assert
         assertEquals(max, connPerRoute.getMaxPerRoute(route));
     }
 
     @Test
     void probeStillAdjustsAfterCoolDownPeriod() {
         // Arrange
         connPerRoute.setMaxPerRoute(route, 4);
         impl.probe(route);
 
         // Manipulate lastRouteProbes to simulate that enough time has passed for the cooldown period
         final Map<HttpRoute, Instant> lastRouteProbes = impl.getLastRouteProbes();
         lastRouteProbes.put(route, Instant.now().minusMillis(DEFAULT_COOL_DOWN_MS + 1));
 
         // Act
         impl.probe(route);
         final long newMax = connPerRoute.getMaxPerRoute(route);
 
         // Assert
         assertEquals(2, newMax); // The cap is set to 2 by default
     }
 
 
     @Test
     void testSetPerHostConnectionCap() {
         connPerRoute.setMaxPerRoute(route, 5);
         impl.setPerHostConnectionCap(10); // Set the cap to a higher value
         impl.backOff(route);
         assertEquals(6, connPerRoute.getMaxPerRoute(route));
     }
 
 
     public void probeUpdatesRemainingAttemptsIndirectly() {
         // Set initial max per route
         connPerRoute.setMaxPerRoute(route, 4);
 
         // Apply backOff twice
         impl.backOff(route);
 
         // Manipulate lastRouteBackoffs to simulate that enough time has passed for the cooldown period
         final Map<HttpRoute, Instant> lastRouteBackoffs = impl.getLastRouteBackoffs();
         lastRouteBackoffs.put(route, Instant.now().minusMillis(DEFAULT_COOL_DOWN_MS + 1));
 
         impl.backOff(route);
 
         // Ensure that connection pool size has increased
         assertEquals(6, connPerRoute.getMaxPerRoute(route));
 
         // Apply probe once
         impl.probe(route);
 
         // Manipulate lastRouteProbes to simulate that enough time has passed for the cooldown period
         final Map<HttpRoute, Instant> lastRouteProbes = impl.getLastRouteProbes();
         lastRouteProbes.put(route, Instant.now().minusMillis(DEFAULT_COOL_DOWN_MS * 2));
 
         // Apply probe once more
         impl.probe(route);
 
         // Check that connection pool size has decreased once, indicating that the remaining attempts were updated
         assertEquals(5, connPerRoute.getMaxPerRoute(route));
     }
 
     @Test
     void linearIncrementTest() {
         final int initialMax = 4;
         connPerRoute.setMaxPerRoute(route, initialMax);
 
         // Manipulate lastRouteBackoffs to simulate that enough time has passed for the cooldown period
         final Map<HttpRoute, Instant> lastRouteBackoffs = impl.getLastRouteBackoffs();
 
         for (int i = 1; i <= 5; i++) {
             // Simulate that enough time has passed for the cooldown period
             lastRouteBackoffs.put(route, Instant.now().minusMillis(DEFAULT_COOL_DOWN_MS + 1));
 
             // Act
             impl.backOff(route);
 
             // Assert
             assertEquals(initialMax + i, connPerRoute.getMaxPerRoute(route));
         }
     }
 
 }