refactor(libs/fraud): fraud tests overhaul (#2039)

The main goal here is to prepare everything for extraction. There was a cyclic dependency and dependence on ExtendedHeader inside of fraud, which blocked the extraction. This patch fixes this in conjunction with cleanings for testing utilities and actual tests.

List of other notable changes:
-  Updates go-header and
	- migrates to the new API for testing in header
- Restructures fraud pkg and extract fraud.Service and related logic into sub pkg fraudserv
	- Keeping only interface definitions inside of the root fraud
- Extracts testing utilities into fraudtest
- Adds sprinkles of documentation

gossip_score.go → fraudserv/gossip_score.go

@@ -1,4 +1,4 @@
-package fraud
+package fraudserv
 
 import (
 	"math"

helpers.go → fraudserv/helpers.go

@@ -1,4 +1,4 @@
-package fraud
+package fraudserv
 
 import (
 	"context"
@@ -7,6 +7,8 @@ import (
 	pubsub "github.com/libp2p/go-libp2p-pubsub"
 	"github.com/libp2p/go-libp2p/core/peer"
 	"github.com/libp2p/go-libp2p/core/protocol"
+
+	"github.com/celestiaorg/celestia-node/libs/fraud"
 )
 
 func PubsubTopicID(fraudType, networkID string) string {
@@ -17,8 +19,12 @@ func protocolID(networkID string) protocol.ID {
 	return protocol.ID(fmt.Sprintf("/%s/fraud/v0.0.1", networkID))
 }
 
-func join(p *pubsub.PubSub, proofType ProofType, networkID string,
-	validate func(context.Context, ProofType, peer.ID, *pubsub.Message) pubsub.ValidationResult) (*pubsub.Topic, error) {
+func join(
+	p *pubsub.PubSub,
+	proofType fraud.ProofType,
+	networkID string,
+	validate func(context.Context, fraud.ProofType, peer.ID, *pubsub.Message) pubsub.ValidationResult,
+) (*pubsub.Topic, error) {
 	topic := PubsubTopicID(proofType.String(), networkID)
 	log.Infow("joining topic", "id", topic)
 	t, err := p.Join(topic)

requester.go → fraudserv/requester.go

@@ -1,4 +1,4 @@
-package fraud
+package fraudserv
 
 import (
 	"context"
@@ -9,7 +9,7 @@ import (
 
 	"github.com/celestiaorg/go-libp2p-messenger/serde"
 
-	pb "github.com/celestiaorg/celestia-node/libs/fraud/pb"
+	pb "github.com/celestiaorg/celestia-node/libs/fraud/fraudserv/pb"
 )
 
 const (

service.go → fraudserv/service.go

@@ -1,4 +1,4 @@
-package fraud
+package fraudserv
 
 import (
 	"bytes"
@@ -9,12 +9,21 @@ import (
 	"sync"
 
 	"github.com/ipfs/go-datastore"
+	logging "github.com/ipfs/go-log/v2"
 	pubsub "github.com/libp2p/go-libp2p-pubsub"
 	"github.com/libp2p/go-libp2p/core/host"
 	"github.com/libp2p/go-libp2p/core/peer"
+	"go.opentelemetry.io/otel"
 	"go.opentelemetry.io/otel/attribute"
 	"go.opentelemetry.io/otel/codes"
 	"go.opentelemetry.io/otel/trace"
+
+	"github.com/celestiaorg/celestia-node/libs/fraud"
+)
+
+var (
+	log    = logging.Logger("fraudserv")
+	tracer = otel.Tracer("fraudserv")
 )
 
 // fraudRequests is the amount of external requests that will be tried to get fraud proofs from
@@ -30,14 +39,14 @@ type ProofService struct {
 	cancel context.CancelFunc
 
 	topicsLk sync.RWMutex
-	topics   map[ProofType]*pubsub.Topic
+	topics   map[fraud.ProofType]*pubsub.Topic
 
 	storesLk sync.RWMutex
-	stores   map[ProofType]datastore.Datastore
+	stores   map[fraud.ProofType]datastore.Datastore
 
 	pubsub *pubsub.PubSub
 	host   host.Host
-	getter headerFetcher
+	getter fraud.HeaderFetcher
 	ds     datastore.Datastore
 
 	syncerEnabled bool
@@ -46,7 +55,7 @@ type ProofService struct {
 func NewProofService(
 	p *pubsub.PubSub,
 	host host.Host,
-	getter headerFetcher,
+	getter fraud.HeaderFetcher,
 	ds datastore.Datastore,
 	syncerEnabled bool,
 	networkID string,
@@ -55,16 +64,16 @@ func NewProofService(
 		pubsub:        p,
 		host:          host,
 		getter:        getter,
-		topics:        make(map[ProofType]*pubsub.Topic),
-		stores:        make(map[ProofType]datastore.Datastore),
+		topics:        make(map[fraud.ProofType]*pubsub.Topic),
+		stores:        make(map[fraud.ProofType]datastore.Datastore),
 		ds:            ds,
 		networkID:     networkID,
 		syncerEnabled: syncerEnabled,
 	}
 }
 
 // registerProofTopics registers proofTypes as pubsub topics to be joined.
-func (f *ProofService) registerProofTopics(proofTypes ...ProofType) error {
+func (f *ProofService) registerProofTopics(proofTypes ...fraud.ProofType) error {
 	for _, proofType := range proofTypes {
 		t, err := join(f.pubsub, proofType, f.networkID, f.processIncoming)
 		if err != nil {
@@ -81,7 +90,7 @@ func (f *ProofService) registerProofTopics(proofTypes ...ProofType) error {
 // if syncer is enabled.
 func (f *ProofService) Start(context.Context) error {
 	f.ctx, f.cancel = context.WithCancel(context.Background())
-	if err := f.registerProofTopics(registeredProofTypes()...); err != nil {
+	if err := f.registerProofTopics(fraud.Registered()...); err != nil {
 		return err
 	}
 	id := protocolID(f.networkID)
@@ -95,13 +104,13 @@ func (f *ProofService) Start(context.Context) error {
 }
 
 // Stop removes the stream handler and cancels the underlying ProofService
-func (f *ProofService) Stop(context.Context) error {
+func (f *ProofService) Stop(context.Context) (err error) {
 	f.host.RemoveStreamHandler(protocolID(f.networkID))
 	f.cancel()
-	return nil
+	return
 }
 
-func (f *ProofService) Subscribe(proofType ProofType) (_ Subscription, err error) {
+func (f *ProofService) Subscribe(proofType fraud.ProofType) (_ fraud.Subscription, err error) {
 	f.topicsLk.Lock()
 	defer f.topicsLk.Unlock()
 	t, ok := f.topics[proofType]
@@ -115,7 +124,7 @@ func (f *ProofService) Subscribe(proofType ProofType) (_ Subscription, err error
 	return &subscription{subs}, nil
 }
 
-func (f *ProofService) Broadcast(ctx context.Context, p Proof) error {
+func (f *ProofService) Broadcast(ctx context.Context, p fraud.Proof) error {
 	bin, err := p.MarshalBinary()
 	if err != nil {
 		return err
@@ -132,7 +141,7 @@ func (f *ProofService) Broadcast(ctx context.Context, p Proof) error {
 // processIncoming encompasses the logic for validating fraud proofs.
 func (f *ProofService) processIncoming(
 	ctx context.Context,
-	proofType ProofType,
+	proofType fraud.ProofType,
 	from peer.ID,
 	msg *pubsub.Message,
 ) pubsub.ValidationResult {
@@ -143,10 +152,10 @@ func (f *ProofService) processIncoming(
 
 	// unmarshal message to the Proof.
 	// Peer will be added to black list if unmarshalling fails.
-	proof, err := Unmarshal(proofType, msg.Data)
+	proof, err := fraud.Unmarshal(proofType, msg.Data)
 	if err != nil {
 		log.Errorw("unmarshalling failed", "err", err)
-		if !errors.Is(err, &errNoUnmarshaler{}) {
+		if !errors.Is(err, &fraud.ErrNoUnmarshaler{}) {
 			f.pubsub.BlacklistPeer(from)
 		}
 		span.RecordError(err)
@@ -201,7 +210,7 @@ func (f *ProofService) processIncoming(
 	return pubsub.ValidationAccept
 }
 
-func (f *ProofService) Get(ctx context.Context, proofType ProofType) ([]Proof, error) {
+func (f *ProofService) Get(ctx context.Context, proofType fraud.ProofType) ([]fraud.Proof, error) {
 	f.storesLk.Lock()
 	store, ok := f.stores[proofType]
 	if !ok {
@@ -214,7 +223,7 @@ func (f *ProofService) Get(ctx context.Context, proofType ProofType) ([]Proof, e
 }
 
 // put adds a fraud proof to the local storage.
-func (f *ProofService) put(ctx context.Context, proofType ProofType, hash string, data []byte) error {
+func (f *ProofService) put(ctx context.Context, proofType fraud.ProofType, hash string, data []byte) error {
 	f.storesLk.Lock()
 	store, ok := f.stores[proofType]
 	if !ok {
@@ -226,7 +235,7 @@ func (f *ProofService) put(ctx context.Context, proofType ProofType, hash string
 }
 
 // verifyLocal checks if a fraud proof has been stored locally.
-func (f *ProofService) verifyLocal(ctx context.Context, proofType ProofType, hash string, data []byte) bool {
+func (f *ProofService) verifyLocal(ctx context.Context, proofType fraud.ProofType, hash string, data []byte) bool {
 	f.storesLk.RLock()
 	storage, ok := f.stores[proofType]
 	f.storesLk.RUnlock()