feat: full NFSv4.2 server and client in pure Go

Assisted-by: GLM 5.3 Flash

internal/nfsclient/timeout_test.go

@@ -0,0 +1,93 @@
+// Copyright (c) 2026 Petr Balvín <opensource@petrbalvin.org> (https://petrbalvin.org)
+// SPDX-License-Identifier: MIT
+
+package nfsclient
+
+import (
+	"net"
+	"testing"
+	"time"
+
+	"sourcedock.dev/petrbalvin/nfs/internal/nfs4"
+)
+
+// A server that accepts and never answers: every call fails at its
+// deadline instead of hanging the process.
+func TestCallTimeout(t *testing.T) {
+	ln, err := net.Listen("tcp", "127.0.0.1:0")
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer ln.Close()
+	go func() {
+		for {
+			conn, err := ln.Accept()
+			if err != nil {
+				return
+			}
+			defer conn.Close()
+		}
+	}()
+
+	cl, err := Dial(ln.Addr().String())
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer cl.Close()
+	cl.Timeout = 40 * time.Millisecond
+	start := time.Now()
+	if _, _, err := cl.call(nfs4.ProcNull, nil); err == nil {
+		t.Fatal("a silent server answered")
+	}
+	if elapsed := time.Since(start); elapsed > 2*time.Second {
+		t.Fatalf("the call took %s, the deadline is 40ms", elapsed)
+	}
+}
+
+// A connection that dies mid call: the waiting caller reports the
+// loss with the cause the reader saw.
+func TestConnectionLost(t *testing.T) {
+	ln, err := net.Listen("tcp", "127.0.0.1:0")
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer ln.Close()
+	accepted := make(chan net.Conn, 1)
+	go func() {
+		conn, err := ln.Accept()
+		if err != nil {
+			return
+		}
+		accepted <- conn
+	}()
+
+	cl, err := Dial(ln.Addr().String())
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer cl.Close()
+	cl.Timeout = 5 * time.Second
+
+	done := make(chan error, 1)
+	go func() {
+		_, _, err := cl.call(nfs4.ProcNull, nil)
+		done <- err
+	}()
+	// The server side of the connection dies: the reader routes the
+	// failure to the waiting call.
+	var server net.Conn
+	select {
+	case server = <-accepted:
+	case <-time.After(3 * time.Second):
+		t.Fatal("the server side never saw the connection")
+	}
+	server.Close()
+	select {
+	case err := <-done:
+		if err == nil {
+			t.Fatal("a lost connection answered")
+		}
+	case <-time.After(3 * time.Second):
+		t.Fatal("the call never noticed the lost connection")
+	}
+}