Add doppel and tls packages

mtglib/internal/tls/init_test.go

@@ -0,0 +1,30 @@
+package tls
+
+import (
+	"encoding/binary"
+
+	"github.com/stretchr/testify/mock"
+)
+
+type WriterMock struct {
+	mock.Mock
+}
+
+func (m *WriterMock) Write(p []byte) (int, error) {
+	args := m.Called(p)
+	return args.Int(0), args.Error(1)
+}
+
+// makeTLSRecord builds a raw TLS record from hardcoded offsets:
+// type(1) + version(2, {3,3}) + length(2, big-endian) + payload.
+func MakeTLSRecord(recordType byte, payload []byte) []byte {
+	buf := make([]byte, 5+len(payload))
+
+	buf[0] = recordType
+	buf[1] = 3
+	buf[2] = 3
+	binary.BigEndian.PutUint16(buf[3:5], uint16(len(payload)))
+	copy(buf[5:], payload)
+
+	return buf
+}