Resolve Redis Client Connection Issue in Integration Test

- Resolves a race condition where a client instance is closed
  before it can be used by another test

persistence-modules/redis/src/main/java/com/baeldung/redis_scan/client/RedisClient.java

@@ -145,5 +145,10 @@ public class RedisClient {
             log.error("Exception caught in flushAll", ex);
         }
     }
+    
+    public void destroyInstance() {
+        jedisPool = null;
+        instance = null;
+    }
 
 }

persistence-modules/redis/src/test/java/com/baeldung/redis_scan/NaiveApproachIntegrationTest.java

@@ -25,13 +25,14 @@ public class NaiveApproachIntegrationTest {
         s.close();
 
         redisServer = new RedisServer(port);
-        redisServer.start();
     }
 
     @AfterClass
     public static void destroy() {
-        if (redisServer.isActive())
+        if (redisServer.isActive()) {
             redisServer.stop();
+            redisClient.destroyInstance();
+        }
     }
 
     @Before

persistence-modules/redis/src/test/java/com/baeldung/redis_scan/ScanStrategyIntegrationTest.java

@@ -32,13 +32,14 @@ public class ScanStrategyIntegrationTest {
         s.close();
 
         redisServer = new RedisServer(port);
-        redisServer.start();
     }
 
     @AfterClass
     public static void destroy() {
-        if (redisServer.isActive())
+        if (redisServer.isActive()) {
             redisServer.stop();
+            redisClient.destroyInstance();
+        }
     }
 
     @Before