[client] Fix stale local records (#3776)

client/internal/dns/test/mock.go

@@ -0,0 +1,26 @@
+package test
+
+import (
+	"net"
+
+	"github.com/miekg/dns"
+)
+
+type MockResponseWriter struct {
+	WriteMsgFunc func(m *dns.Msg) error
+}
+
+func (rw *MockResponseWriter) WriteMsg(m *dns.Msg) error {
+	if rw.WriteMsgFunc != nil {
+		return rw.WriteMsgFunc(m)
+	}
+	return nil
+}
+
+func (rw *MockResponseWriter) LocalAddr() net.Addr       { return nil }
+func (rw *MockResponseWriter) RemoteAddr() net.Addr      { return nil }
+func (rw *MockResponseWriter) Write([]byte) (int, error) { return 0, nil }
+func (rw *MockResponseWriter) Close() error              { return nil }
+func (rw *MockResponseWriter) TsigStatus() error         { return nil }
+func (rw *MockResponseWriter) TsigTimersOnly(bool)       {}
+func (rw *MockResponseWriter) Hijack()                   {}