lnwire: replace all wire msg tests with a single property-based test

This commit does away with all the old manual message equality tests
and replace it with a single property-based test that uses the
testing/quick package. This test uses a single scenario which MUST hold
for all the messages type and all possible messages generated for those
types. As a result we are able to do away with all the prior manually
generated test data as the fuzzer to scan the input space looking for a
message that violates the scenario.

lnwire/update_add_htlc_test.go

@@ -1,39 +0,0 @@
-package lnwire
-
-import (
-	"bytes"
-	"reflect"
-	"testing"
-
-	"github.com/roasbeef/btcutil"
-)
-
-func TestUpdateAddHTLCEncodeDecode(t *testing.T) {
-	// First create a new UPAH message.
-	addReq := &UpdateAddHTLC{
-		ChanID:      ChannelID(revHash),
-		ID:          99,
-		Expiry:      uint32(144),
-		Amount:      btcutil.Amount(123456000),
-		PaymentHash: revHash,
-	}
-	copy(addReq.OnionBlob[:], bytes.Repeat([]byte{23}, OnionPacketSize))
-
-	// Next encode the HTLCAR message into an empty bytes buffer.
-	var b bytes.Buffer
-	if err := addReq.Encode(&b, 0); err != nil {
-		t.Fatalf("unable to encode HTLCAddRequest: %v", err)
-	}
-
-	// Deserialize the encoded UPAH message into a new empty struct.
-	addReq2 := &UpdateAddHTLC{}
-	if err := addReq2.Decode(&b, 0); err != nil {
-		t.Fatalf("unable to decode HTLCAddRequest: %v", err)
-	}
-
-	// Assert equality of the two instances.
-	if !reflect.DeepEqual(addReq, addReq2) {
-		t.Fatalf("encode/decode error messages don't match %#v vs %#v",
-			addReq, addReq2)
-	}
-}