Typo fix.

Signed-off-by: Yury-Fridlyand <[email protected]>

java/client/src/test/java/glide/api/RedisClusterClientTest.java

@@ -123,7 +123,7 @@ private static class TestCommandManager extends CommandManager {
 
         public TestCommandManager(Response responseToReturn) {
             super(null);
-            response = responseToReturn;
+            response = responseToReturn != null ? responseToReturn : Response.newBuilder().build();
         }
 
         @Override