move gotd fork into repo. (#111)

- update to latest telegram layer
- remove some references to fields in tg.Entities that don't exist in
the schema
- originally added here:
https://github.com/beeper/td/commit/820929062a2ba0104397bc01235ab58a9cff780e
  - referenced here
-
https://github.com/mautrix/telegramgo/commit/124f0967ed195b5a380c9bd02e170ada9710dde3
-
https://github.com/mautrix/telegramgo/commit/4205047aab2e0639217148b5d125bfaab668bd8e

pkg/gotd/mtproto/conn_test.go

@@ -0,0 +1,92 @@
+package mtproto
+
+import (
+	"context"
+	"crypto/md5"
+	"fmt"
+	"math/rand"
+	"os"
+	"path/filepath"
+	"strings"
+	"testing"
+	"time"
+
+	"github.com/stretchr/testify/assert"
+	"go.uber.org/zap"
+
+	"go.mau.fi/mautrix-telegram/pkg/gotd/bin"
+	"go.mau.fi/mautrix-telegram/pkg/gotd/crypto"
+	"go.mau.fi/mautrix-telegram/pkg/gotd/mt"
+	"go.mau.fi/mautrix-telegram/pkg/gotd/proto"
+	"go.mau.fi/mautrix-telegram/pkg/gotd/rpc"
+	"go.mau.fi/mautrix-telegram/pkg/gotd/tg"
+	"go.mau.fi/mautrix-telegram/pkg/gotd/tmap"
+)
+
+type testHandler func(msgID int64, seqNo int32, body bin.Encoder) (bin.Encoder, error)
+
+type testClientOption func(o Options)
+
+func newTestClient(h testHandler, opts ...testClientOption) *Conn {
+	var engine *rpc.Engine
+
+	engine = rpc.New(func(ctx context.Context, msgID int64, seqNo int32, in bin.Encoder) error {
+		if response, err := h(msgID, seqNo, in); err != nil {
+			engine.NotifyError(msgID, err)
+		} else {
+			var b bin.Buffer
+			if err := b.Encode(response); err != nil {
+				return err
+			}
+			return engine.NotifyResult(msgID, &b)
+		}
+		return nil
+	}, rpc.Options{})
+
+	opt := Options{
+		Logger:    zap.NewNop(),
+		Random:    rand.New(rand.NewSource(1)),
+		Key:       crypto.Key{}.WithID(),
+		MessageID: proto.NewMessageIDGen(time.Now),
+
+		engine: engine,
+	}
+	for _, o := range opts {
+		o(opt)
+	}
+
+	return New(nil, opt)
+}
+
+// newCorpusTracer will save incoming messages to corpus folder.
+//
+// Usage:
+//
+//	client.trace.OnMessage = newCorpusTracer(t)
+//
+// nolint: deadcode,unused // optional
+func newCorpusTracer(t testing.TB) func(b *bin.Buffer) {
+	types := tmap.New(
+		mt.TypesMap(),
+		tg.TypesMap(),
+		proto.TypesMap(),
+	)
+	dir := filepath.Join("..", "_fuzz", "handle_message", "corpus")
+
+	return func(b *bin.Buffer) {
+		id, _ := b.PeekID()
+		h := md5.Sum(b.Buf)
+		name := types.Get(id)
+		if name == "" {
+			name = "unknown"
+		}
+		if idx := strings.Index(name, "#"); idx > 0 {
+			// Removing type id from name.
+			name = name[:idx]
+		}
+		base := fmt.Sprintf("trace_%x_%s_%x",
+			id, name, h,
+		)
+		assert.NoError(t, os.WriteFile(filepath.Join(dir, base), b.Buf, 0600))
+	}
+}