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

win-nvim/tests/integration_test.rs

@@ -42,7 +42,6 @@ fn read_message(stdout: &mut std::process::ChildStdout) -> Option<Value> {
 
 #[test]
 fn test_mcp_initialization_and_tools_list() {
-    // Determine the path to the built binary.
     let mut nvim_exe = std::env::current_exe().unwrap();
     nvim_exe.pop();
     nvim_exe.pop();
@@ -58,6 +57,17 @@ fn test_mcp_initialization_and_tools_list() {
     let mut stdin = child.stdin.take().expect("Failed to open stdin");
     let mut stdout = child.stdout.take().expect("Failed to open stdout");
 
+    // 0. Test server/discover (probe)
+    let discover_req = json!({
+        "jsonrpc": "2.0",
+        "method": "server/discover",
+        "params": {},
+        "id": 0
+    });
+    send_message(&mut stdin, discover_req);
+    let discover_resp = read_message(&mut stdout).expect("Failed to read server/discover response");
+    assert_eq!(discover_resp["error"]["code"], -32601);
+
     // 1. Test Initialize
     let init_req = json!({
         "jsonrpc": "2.0",
@@ -73,7 +83,10 @@ fn test_mcp_initialization_and_tools_list() {
         "id": 1
     });
 
-    send_message(&mut stdin, init_req);
+    // Send initialize using JSONL format!
+    let s = serde_json::to_string(&init_req).unwrap();
+    stdin.write_all(format!("{}\n", s).as_bytes()).unwrap();
+    stdin.flush().unwrap();
     
     let init_resp = read_message(&mut stdout).expect("Failed to read initialize response");
     
@@ -102,11 +115,31 @@ fn test_mcp_initialization_and_tools_list() {
     let tools = tools_resp["result"]["tools"].as_array().expect("result.tools must be an array");
     assert!(!tools.is_empty(), "Server must expose at least one tool");
     
-    // Verify a specific tool exists
     let has_get_active_buffer = tools.iter().any(|t| t["name"] == "nvim_get_active_buffer");
     assert!(has_get_active_buffer, "Missing nvim_get_active_buffer tool");
 
-    // Kill the child process cleanly
+    // 3. Test negative scenario: tools/call when Neovim is not running
+    // Since Neovim is not guaranteed to be running on the test agent's system,
+    // calling a Neovim-specific tool should gracefully return a JSON-RPC error.
+    let call_req = json!({
+        "jsonrpc": "2.0",
+        "method": "tools/call",
+        "params": {
+            "name": "nvim_get_active_buffer",
+            "arguments": {}
+        },
+        "id": 3
+    });
+    
+    send_message(&mut stdin, call_req);
+    
+    let call_resp = read_message(&mut stdout).expect("Failed to read tools/call response");
+    
+    assert_eq!(call_resp["jsonrpc"], "2.0");
+    assert_eq!(call_resp["id"], 3);
+    assert!(call_resp.get("error").is_some(), "Expected an error response since Neovim shouldn't be running");
+    assert_eq!(call_resp["error"]["code"], -32603); // Internal Error
+
     child.kill().expect("Failed to kill child");
     child.wait().expect("Failed to wait on child");
 }