Add new obfuscation package

mtglib/internal/obfuscation/obfuscator_fuzz_test.go

@@ -0,0 +1,63 @@
+package obfuscation_test
+
+import (
+	"bytes"
+	"testing"
+
+	"github.com/9seconds/mtg/v2/internal/testlib"
+	"github.com/9seconds/mtg/v2/mtglib"
+	"github.com/9seconds/mtg/v2/mtglib/internal/obfuscation"
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/mock"
+)
+
+func FuzzClientServerHandshakes(f *testing.F) {
+	f.Add(int16(1), make([]byte, mtglib.SecretKeyLength))
+
+	f.Fuzz(func(t *testing.T, dc int16, data []byte) {
+		if dc <= 0 {
+			dc = 1
+		}
+
+		client := obfuscation.Obfuscator{
+			Secret: data,
+		}
+		server := client
+
+		clientToServerBuf := &bytes.Buffer{}
+
+		writeConnMock := &testlib.EssentialsConnMock{}
+		writeConnMock.
+			On("Write", mock.AnythingOfType("[]uint8")).
+			Once().
+			Return(64, nil).
+			Run(func(args mock.Arguments) {
+				arg := args.Get(0).([]byte)
+				n, err := clientToServerBuf.Write(arg)
+				assert.Equal(t, 64, n)
+				assert.NoError(t, err)
+			})
+
+		readConnMock := &testlib.EssentialsConnMock{}
+		readConnMock.
+			On("Read", mock.AnythingOfType("[]uint8")).
+			Once().
+			Return(64, nil).
+			Run(func(args mock.Arguments) {
+				arg := args.Get(0).([]byte)
+				n, err := clientToServerBuf.Read(arg)
+				assert.Equal(t, 64, n)
+				assert.NoError(t, err)
+			})
+
+		_, err := client.SendHandshake(writeConnMock, int(dc))
+		assert.NoError(t, err)
+
+		readDc, _, err := server.ReadHandshake(readConnMock)
+		assert.NoError(t, err)
+		assert.EqualValues(t, dc, readDc)
+
+		writeConnMock.AssertExpectations(t)
+		readConnMock.AssertExpectations(t)
+	})
+}