Begin work on full device<->device unit-test

To simulate a full interaction between two WireGuard
instances without networking, using dummy instances of the interfaces

endpoint_test.go

@@ -0,0 +1,48 @@
+package main
+
+import (
+	"math/rand"
+	"net"
+)
+
+type DummyEndpoint struct {
+	src [16]byte
+	dst [16]byte
+}
+
+func CreateDummyEndpoint() (*DummyEndpoint, error) {
+	var end DummyEndpoint
+	if _, err := rand.Read(end.src[:]); err != nil {
+		return nil, err
+	}
+	_, err := rand.Read(end.dst[:])
+	return &end, err
+}
+
+func (e *DummyEndpoint) ClearSrc() {}
+
+func (e *DummyEndpoint) SrcToString() string {
+	var addr net.UDPAddr
+	addr.IP = e.SrcIP()
+	addr.Port = 1000
+	return addr.String()
+}
+
+func (e *DummyEndpoint) DstToString() string {
+	var addr net.UDPAddr
+	addr.IP = e.DstIP()
+	addr.Port = 1000
+	return addr.String()
+}
+
+func (e *DummyEndpoint) SrcToBytes() []byte {
+	return e.src[:]
+}
+
+func (e *DummyEndpoint) DstIP() net.IP {
+	return e.dst[:]
+}
+
+func (e *DummyEndpoint) SrcIP() net.IP {
+	return e.src[:]
+}