refactor(mcp): strip sse fallback architecture in favor of pure websockets and fix nvim NDJSON bug

stub/tests/negative_scenarios.rs

@@ -0,0 +1,88 @@
+use std::process::Stdio;
+use std::time::{Duration, Instant};
+use tokio::process::Command;
+
+fn get_stub_exe() -> std::path::PathBuf {
+    let manifest_dir = std::path::PathBuf::from(env!("CARGO_MANIFEST_DIR"));
+    let debug_dir = manifest_dir.parent().unwrap().join("target").join("debug");
+    debug_dir.join(format!("mcp-memory-stub{}", std::env::consts::EXE_SUFFIX))
+}
+
+#[tokio::test]
+async fn test_stub_connection_refused() {
+    let _ = std::process::Command::new("cargo").arg("build").arg("--bin").arg("mcp-memory-stub").status();
+
+    let target = "http://127.0.0.1:49999";
+    
+    let start = Instant::now();
+    let mut child = Command::new(get_stub_exe())
+        .arg("--target")
+        .arg(target)
+        .stdin(Stdio::null()) // close stdin immediately to simulate EOF
+        .spawn()
+        .expect("Failed to execute stub");
+        
+    let res = tokio::time::timeout(Duration::from_secs(5), child.wait()).await;
+    let elapsed = start.elapsed();
+    
+    assert!(res.is_ok(), "Stub hung on connection refused! Took {:?}", elapsed);
+}
+
+#[tokio::test]
+async fn test_stub_handles_eof_cleanly() {
+    let _ = std::process::Command::new("cargo").arg("build").arg("--bin").arg("mcp-memory-stub").status();
+
+    let target = "http://127.0.0.1:49998";
+    
+    let mut child = Command::new(get_stub_exe())
+        .arg("--target")
+        .arg(target)
+        .stdin(Stdio::piped())
+        .stdout(Stdio::piped())
+        .stderr(Stdio::piped())
+        .spawn()
+        .expect("Failed to execute stub");
+        
+    if let Some(mut stdin) = child.stdin.take() {
+        use tokio::io::AsyncWriteExt;
+        let msg = "Content-Length: 51\r\n\r\n{\"jsonrpc\":\"2.0\",\"method\":\"tools/list\",\"params\":{},\"id\":1}";
+        stdin.write_all(msg.as_bytes()).await.unwrap();
+    } // stdin dropped here
+    
+    let start = Instant::now();
+    let res = tokio::time::timeout(Duration::from_secs(5), child.wait()).await;
+    let elapsed = start.elapsed();
+    
+    assert!(res.is_ok(), "Stub hung after EOF! Took {:?}", elapsed);
+}
+
+#[tokio::test]
+async fn test_stub_sse_fallback_failure() {
+    let _ = std::process::Command::new("cargo").arg("build").arg("--bin").arg("mcp-memory-stub").status();
+
+    let listener = tokio::net::TcpListener::bind("127.0.0.1:0").await.unwrap();
+    let local_addr = listener.local_addr().unwrap();
+    let target = format!("http://127.0.0.1:{}", local_addr.port());
+    
+    tokio::spawn(async move {
+        while let Ok((mut socket, _)) = listener.accept().await {
+            use tokio::io::AsyncReadExt;
+            let mut buf = [0; 1024];
+            let _ = socket.read(&mut buf).await;
+            drop(socket);
+        }
+    });
+
+    let start = Instant::now();
+    let mut child = Command::new(get_stub_exe())
+        .arg("--target")
+        .arg(target)
+        .stdin(Stdio::null()) 
+        .spawn()
+        .expect("Failed to execute stub");
+        
+    let res = tokio::time::timeout(Duration::from_secs(5), child.wait()).await;
+    let elapsed = start.elapsed();
+    
+    assert!(res.is_ok(), "Stub hung on fallback failure! Took {:?}", elapsed);
+}