add dhcp failing test

dhcpv4/dhcp_test.go

@@ -0,0 +1,66 @@
+package dhcpv4
+
+import (
+	"testing"
+)
+
+func TestClientServer(t *testing.T) {
+	svAddr := [4]byte{192, 168, 1, 1}
+	clAddr := svAddr
+	clAddr[3]++
+	var sv Server
+	var cl Client
+	err := cl.BeginRequest(123, RequestConfig{
+		RequestedAddr:      clAddr,
+		ClientHardwareAddr: [6]byte{1, 2, 3, 4, 5, 6},
+		Hostname:           "lneto",
+	})
+	if err != nil {
+		t.Fatal(err)
+	}
+	assertClState := func(state ClientState) {
+		t.Helper()
+		if state != cl.State() {
+			t.Errorf("want client state %s, got %s", state.String(), cl.State().String())
+		}
+	}
+	sv.Reset(svAddr, DefaultServerPort)
+	// CLIENT DISCOVER.
+	assertClState(StateInit)
+	var buf [1024]byte
+	n, err := cl.Encapsulate(buf[:], 0)
+	if err != nil {
+		t.Fatal(err)
+	} else if n == 0 {
+		t.Fatal("no data exchanged")
+	}
+	assertClState(StateSelecting)
+	err = sv.Demux(buf[:n], 0)
+	if err != nil {
+		t.Fatal(err)
+	}
+	// SERVER REPLY OFFER
+	n, err = sv.Encapsulate(buf[:], 0)
+	if err != nil {
+		t.Fatal(err)
+	} else if n == 0 {
+		t.Fatal("no data exchanged")
+	}
+	err = cl.Demux(buf[:n], 0)
+	if err != nil {
+		t.Fatal(err)
+	}
+	assertClState(StateRequesting)
+
+	// CLIENT SEND OUT ACK.
+	n, err = cl.Encapsulate(buf[:], 0)
+	if err != nil {
+		t.Fatal(err)
+	} else if n == 0 {
+		t.Fatal("no data exchanged")
+	}
+	err = sv.Demux(buf[:n], 0)
+	if err != nil {
+		t.Fatal(err)
+	}
+}