Allow router to be shutdown for tests

controller/network/network.go

@@ -591,3 +591,20 @@ func (network *Network) GetServiceCache() Cache {
 type Cache interface {
 	RemoveFromCache(id string)
 }
+
+type MultipleErrors []error
+
+func (e MultipleErrors) Error() string {
+	if len(e) == 0 {
+		return "no errors occurred"
+	}
+	if len(e) == 1 {
+		return e[0].Error()
+	}
+	buf := strings.Builder{}
+	buf.WriteString("multiple errors occurred")
+	for idx, err := range e {
+		buf.WriteString(fmt.Sprintf(" %v: %v", idx, err))
+	}
+	return buf.String()
+}