multi: move Input interface and related code

This commit is a step to split the lnwallet package. It puts the Input
interface and implementations in a separate package along with all their
dependencies from lnwallet.

input/txout_test.go

@@ -0,0 +1,46 @@
+package input
+
+import (
+	"bytes"
+	"reflect"
+	"testing"
+
+	"github.com/btcsuite/btcd/wire"
+)
+
+func TestTxOutSerialization(t *testing.T) {
+	txo := wire.TxOut{
+		Value: 1e7,
+		PkScript: []byte{
+			0x41, // OP_DATA_65
+			0x04, 0xd6, 0x4b, 0xdf, 0xd0, 0x9e, 0xb1, 0xc5,
+			0xfe, 0x29, 0x5a, 0xbd, 0xeb, 0x1d, 0xca, 0x42,
+			0x81, 0xbe, 0x98, 0x8e, 0x2d, 0xa0, 0xb6, 0xc1,
+			0xc6, 0xa5, 0x9d, 0xc2, 0x26, 0xc2, 0x86, 0x24,
+			0xe1, 0x81, 0x75, 0xe8, 0x51, 0xc9, 0x6b, 0x97,
+			0x3d, 0x81, 0xb0, 0x1c, 0xc3, 0x1f, 0x04, 0x78,
+			0x34, 0xbc, 0x06, 0xd6, 0xd6, 0xed, 0xf6, 0x20,
+			0xd1, 0x84, 0x24, 0x1a, 0x6a, 0xed, 0x8b, 0x63,
+			0xa6, // 65-byte signature
+			0xac, // OP_CHECKSIG
+		},
+	}
+
+	var buf bytes.Buffer
+
+	if err := writeTxOut(&buf, &txo); err != nil {
+		t.Fatalf("unable to serialize txout: %v", err)
+	}
+
+	var deserializedTxo wire.TxOut
+	if err := readTxOut(&buf, &deserializedTxo); err != nil {
+		t.Fatalf("unable to deserialize txout: %v", err)
+	}
+
+	if !reflect.DeepEqual(txo, deserializedTxo) {
+		t.Fatalf("original and deserialized txouts are different:\n"+
+			"original     : %+v\n"+
+			"deserialized : %+v\n",
+			txo, deserializedTxo)
+	}
+}