add tests

netdev_fake_test.go

@@ -0,0 +1,85 @@
+// TINYGO test helper: an in-memory fake netdever for exercising the
+// netdev-backed net APIs without real hardware/OS sockets.
+
+package net
+
+import (
+	"net/netip"
+	"testing"
+	"time"
+)
+
+// fakeNetdev embeds nopNetdev (whose methods all error) and overrides only
+// the calls a given test needs. Recorded fields let tests assert on how the
+// net package drove the device.
+type fakeNetdev struct {
+	nopNetdev
+
+	// GetHostByName control.
+	hostIP  netip.Addr
+	hostErr error
+
+	// Socket/Bind/Connect control + capture.
+	socketFD   int
+	socketErr  error
+	socketArgs [3]int
+	bindErr    error
+	bindAddr   netip.AddrPort
+	connectErr error
+
+	// Send/Recv control + capture.
+	sent     []byte // accumulates everything written via Send
+	sendErr  error
+	recvData []byte // returned (once) by Recv
+	recvErr  error
+
+	closedFDs []int
+}
+
+func (f *fakeNetdev) GetHostByName(name string) (netip.Addr, error) {
+	return f.hostIP, f.hostErr
+}
+
+func (f *fakeNetdev) Socket(domain, stype, protocol int) (int, error) {
+	f.socketArgs = [3]int{domain, stype, protocol}
+	return f.socketFD, f.socketErr
+}
+
+func (f *fakeNetdev) Bind(sockfd int, ip netip.AddrPort) error {
+	f.bindAddr = ip
+	return f.bindErr
+}
+
+func (f *fakeNetdev) Connect(sockfd int, host string, ip netip.AddrPort) error {
+	return f.connectErr
+}
+
+func (f *fakeNetdev) Send(sockfd int, buf []byte, flags int, deadline time.Time) (int, error) {
+	if f.sendErr != nil {
+		return -1, f.sendErr
+	}
+	f.sent = append(f.sent, buf...)
+	return len(buf), nil
+}
+
+func (f *fakeNetdev) Recv(sockfd int, buf []byte, flags int, deadline time.Time) (int, error) {
+	if f.recvErr != nil {
+		return -1, f.recvErr
+	}
+	n := copy(buf, f.recvData)
+	f.recvData = f.recvData[n:]
+	return n, nil
+}
+
+func (f *fakeNetdev) Close(sockfd int) error {
+	f.closedFDs = append(f.closedFDs, sockfd)
+	return nil
+}
+
+// withNetdev installs d as the package netdev for the duration of the test.
+func withNetdev(t *testing.T, d netdever) {
+	t.Helper()
+	old := netdev
+	netdev = d
+	t.Cleanup(func() { netdev = old })
+}