add: decrement work counter error test

src/async_resolver/state_block.rs

@@ -155,8 +155,28 @@ mod state_block_tests {
         }
     }
 
+    #[test]
+    fn decrement_work_counter_error() {
+        let ip_addr = IpAddr::V4(Ipv4Addr::new(192, 168, 0, 1));
+        let port = 53;
+        let key = String::from("key");
+        let algorithm = String::from("algorithm");
+        let udp_connection = ClientUDPConnection::new_default(ip_addr, Duration::from_secs(100));
+        let tcp_connection = ClientTCPConnection::new_default(ip_addr, Duration::from_secs(100));
+        let info = ServerInfo::new(ip_addr, port, key, algorithm, udp_connection, tcp_connection);
 
+        let info_arc = Arc::new(info);
+        let servers = vec![info_arc];
 
+        let mut state_block = StateBlock::new(1, 2, servers);
+        assert_eq!(state_block.get_work_counter(), 1);
 
+        if let Ok(_) = state_block.decrement_work_counter() {
+            assert_eq!(state_block.get_work_counter(), 0);
+        }
 
+        if let Err(ResolverError::RetriesLimitExceeded) = state_block.decrement_work_counter() {
+            assert_eq!(state_block.get_work_counter(), 0);
+        }
+    }
 }