test HTTP connection reuse with new zstd fix

tests/zstd.rs

@@ -296,6 +296,113 @@ async fn test_chunked_fragmented_multiple_frames_in_one_chunk() {
     assert!(start.elapsed() >= DELAY_BETWEEN_RESPONSE_PARTS - DELAY_MARGIN);
 }
 
+#[tokio::test]
+async fn test_connection_reuse_with_chunked_fragmented_multiple_frames_in_one_chunk() {
+    // Define constants for delay and timing margin
+    const DELAY_BETWEEN_RESPONSE_PARTS: tokio::time::Duration =
+        tokio::time::Duration::from_millis(1000); // 1-second delay
+    const DELAY_MARGIN: tokio::time::Duration = tokio::time::Duration::from_millis(50); // Margin for timing assertions
+
+    // We will record the peer addresses of each client request here
+    let peer_addrs = std::sync::Arc::new(std::sync::Mutex::new(Vec::<std::net::SocketAddr>::new()));
+    let peer_addrs_clone = peer_addrs.clone();
+
+    // Set up a low-level server (it will reuse existing client connection, executing callback for each client request)
+    let server = server::low_level_with_response(move |_raw_request, client_socket| {
+        let peer_addrs = peer_addrs_clone.clone();
+        Box::new(async move {
+            // Split RESPONSE_CONTENT into two parts
+            let mid = RESPONSE_CONTENT.len() / 2;
+            let part1 = &RESPONSE_CONTENT[0..mid];
+            let part2 = &RESPONSE_CONTENT[mid..];
+
+            // Compress each part separately to create two ZSTD frames
+            let compressed_part1 = zstd_compress(part1.as_bytes());
+            let compressed_part2 = zstd_compress(part2.as_bytes());
+
+            // Concatenate the frames into a single chunk's data
+            let chunk_data = [compressed_part1.as_slice(), compressed_part2.as_slice()].concat();
+
+            // Calculate the chunk size in bytes
+            let chunk_size = chunk_data.len();
+
+            // Prepare the initial response part: headers + chunk size
+            let headers = [
+                COMPRESSED_RESPONSE_HEADERS, // e.g., "HTTP/1.1 200 OK\r\nContent-Encoding: zstd\r\n"
+                b"Transfer-Encoding: chunked\r\n\r\n", // Indicate chunked encoding
+                format!("{:x}\r\n", chunk_size).as_bytes(), // Chunk size in hex
+            ]
+            .concat();
+
+            // Send headers + chunk size + chunk data
+            client_socket
+                .write_all([headers.as_slice(), &chunk_data].concat().as_slice())
+                .await
+                .expect("write_all failed");
+            client_socket.flush().await.expect("flush failed");
+
+            // Introduce a delay to simulate fragmentation
+            tokio::time::sleep(DELAY_BETWEEN_RESPONSE_PARTS).await;
+
+            peer_addrs
+                .lock()
+                .unwrap()
+                .push(client_socket.peer_addr().unwrap());
+
+            // Send chunk terminator + final chunk
+            client_socket
+                .write_all(b"\r\n0\r\n\r\n")
+                .await
+                .expect("write_all failed");
+            client_socket.flush().await.expect("flush failed");
+        })
+    });
+
+    let client = reqwest::Client::builder()
+        .pool_idle_timeout(std::time::Duration::from_secs(30))
+        .pool_max_idle_per_host(1)
+        .build()
+        .unwrap();
+
+    const NUMBER_OF_REQUESTS: usize = 5;
+
+    for _ in 0..NUMBER_OF_REQUESTS {
+        // Record the start time for delay verification
+        let start = tokio::time::Instant::now();
+
+        let res = client
+            .get(format!("http://{}/", server.addr()))
+            .send()
+            .await
+            .expect("Failed to get response");
+
+        // Verify the decompressed response matches the original content
+        assert_eq!(
+            res.text().await.expect("Failed to read text"),
+            RESPONSE_CONTENT
+        );
+        assert!(start.elapsed() >= DELAY_BETWEEN_RESPONSE_PARTS - DELAY_MARGIN);
+    }
+
+    drop(client);
+
+    // Check that all peer addresses are the same
+    let peer_addrs = peer_addrs.lock().unwrap();
+    assert_eq!(
+        peer_addrs.len(),
+        NUMBER_OF_REQUESTS,
+        "Expected {} peer addresses, but got {}",
+        NUMBER_OF_REQUESTS,
+        peer_addrs.len()
+    );
+    let first_addr = peer_addrs[0];
+    assert!(
+        peer_addrs.iter().all(|addr| addr == &first_addr),
+        "All peer addresses should be the same, but found differences: {:?}",
+        peer_addrs
+    );
+}
+
 #[tokio::test]
 async fn test_chunked_fragmented_response_1() {
     const DELAY_BETWEEN_RESPONSE_PARTS: tokio::time::Duration =