Bucky/fix evidence halt (#34)

* consensus: createProposalBlock function

* blockExecutor.CreateProposalBlock

- factored out of consensus pkg into a method on blockExec
- new private interfaces for mempool ("txNotifier") and evpool with one function each
- consensus tests still require more mempool methods

* failing test for CreateProposalBlock

* Fix bug in include evidece into block

* evidence: change maxBytes to maxSize

* MaxEvidencePerBlock

- changed to return both the max number and the max bytes
- preparation for #2590

* changelog

* fix linter

* Fix from review

Co-Authored-By: ebuchman <ethan@coinculture.info>

CHANGELOG_PENDING.md

@@ -1,4 +1,4 @@
-## v0.29.0
+## v0.28.1
 
 *TBD*
 
@@ -21,3 +21,4 @@ Special thanks to external contributors on this release:
 ### IMPROVEMENTS:
 
 ### BUG FIXES:
+- [consensus] \#? Fix consensus halt from proposing blocks with too much evidence

consensus/mempool_test.go

@@ -10,6 +10,7 @@ import (
 
 	"github.com/tendermint/tendermint/abci/example/code"
 	abci "github.com/tendermint/tendermint/abci/types"
+	sm "github.com/tendermint/tendermint/state"
 	"github.com/tendermint/tendermint/types"
 )
 
@@ -17,12 +18,17 @@ func init() {
 	config = ResetConfig("consensus_mempool_test")
 }
 
+// for testing
+func assertMempool(txn txNotifier) sm.Mempool {
+	return txn.(sm.Mempool)
+}
+
 func TestMempoolNoProgressUntilTxsAvailable(t *testing.T) {
 	config := ResetConfig("consensus_mempool_txs_available_test")
 	config.Consensus.CreateEmptyBlocks = false
 	state, privVals := randGenesisState(1, false, 10)
 	cs := newConsensusStateWithConfig(config, state, privVals[0], NewCounterApplication())
-	cs.mempool.EnableTxsAvailable()
+	assertMempool(cs.txNotifier).EnableTxsAvailable()
 	height, round := cs.Height, cs.Round
 	newBlockCh := subscribe(cs.eventBus, types.EventQueryNewBlock)
 	startTestRound(cs, height, round)
@@ -40,7 +46,7 @@ func TestMempoolProgressAfterCreateEmptyBlocksInterval(t *testing.T) {
 	config.Consensus.CreateEmptyBlocksInterval = ensureTimeout
 	state, privVals := randGenesisState(1, false, 10)
 	cs := newConsensusStateWithConfig(config, state, privVals[0], NewCounterApplication())
-	cs.mempool.EnableTxsAvailable()
+	assertMempool(cs.txNotifier).EnableTxsAvailable()
 	height, round := cs.Height, cs.Round
 	newBlockCh := subscribe(cs.eventBus, types.EventQueryNewBlock)
 	startTestRound(cs, height, round)
@@ -55,7 +61,7 @@ func TestMempoolProgressInHigherRound(t *testing.T) {
 	config.Consensus.CreateEmptyBlocks = false
 	state, privVals := randGenesisState(1, false, 10)
 	cs := newConsensusStateWithConfig(config, state, privVals[0], NewCounterApplication())
-	cs.mempool.EnableTxsAvailable()
+	assertMempool(cs.txNotifier).EnableTxsAvailable()
 	height, round := cs.Height, cs.Round
 	newBlockCh := subscribe(cs.eventBus, types.EventQueryNewBlock)
 	newRoundCh := subscribe(cs.eventBus, types.EventQueryNewRound)
@@ -91,7 +97,7 @@ func deliverTxsRange(cs *ConsensusState, start, end int) {
 	for i := start; i < end; i++ {
 		txBytes := make([]byte, 8)
 		binary.BigEndian.PutUint64(txBytes, uint64(i))
-		err := cs.mempool.CheckTx(txBytes, nil)
+		err := assertMempool(cs.txNotifier).CheckTx(txBytes, nil)
 		if err != nil {
 			panic(fmt.Sprintf("Error after CheckTx: %v", err))
 		}
@@ -141,7 +147,7 @@ func TestMempoolRmBadTx(t *testing.T) {
 		// Try to send the tx through the mempool.
 		// CheckTx should not err, but the app should return a bad abci code
 		// and the tx should get removed from the pool
-		err := cs.mempool.CheckTx(txBytes, func(r *abci.Response) {
+		err := assertMempool(cs.txNotifier).CheckTx(txBytes, func(r *abci.Response) {
 			if r.GetCheckTx().Code != code.CodeTypeBadNonce {
 				t.Fatalf("expected checktx to return bad nonce, got %v", r)
 			}
@@ -153,7 +159,7 @@ func TestMempoolRmBadTx(t *testing.T) {
 
 		// check for the tx
 		for {
-			txs := cs.mempool.ReapMaxBytesMaxGas(int64(len(txBytes)), -1)
+			txs := assertMempool(cs.txNotifier).ReapMaxBytesMaxGas(int64(len(txBytes)), -1)
 			if len(txs) == 0 {
 				emptyMempoolCh <- struct{}{}
 				return

consensus/reactor_test.go

@@ -225,7 +225,7 @@ func TestReactorCreatesBlockWhenEmptyBlocksFalse(t *testing.T) {
 	defer stopConsensusNet(log.TestingLogger(), reactors, eventBuses)
 
 	// send a tx
-	if err := css[3].mempool.CheckTx([]byte{1, 2, 3}, nil); err != nil {
+	if err := assertMempool(css[3].txNotifier).CheckTx([]byte{1, 2, 3}, nil); err != nil {
 		//t.Fatal(err)
 	}
 
@@ -448,7 +448,7 @@ func waitForAndValidateBlock(t *testing.T, n int, activeVals map[string]struct{}
 		err := validateBlock(newBlock, activeVals)
 		assert.Nil(t, err)
 		for _, tx := range txs {
-			err := css[j].mempool.CheckTx(tx, nil)
+			err := assertMempool(css[j].txNotifier).CheckTx(tx, nil)
 			assert.Nil(t, err)
 		}
 	}, css)

consensus/replay_file.go

@@ -137,7 +137,7 @@ func (pb *playback) replayReset(count int, newStepCh chan interface{}) error {
 	pb.cs.Wait()
 
 	newCS := NewConsensusState(pb.cs.config, pb.genesisState.Copy(), pb.cs.blockExec,
-		pb.cs.blockStore, pb.cs.mempool, pb.cs.evpool)
+		pb.cs.blockStore, pb.cs.txNotifier, pb.cs.evpool)
 	newCS.SetEventBus(pb.cs.eventBus)
 	newCS.startForReplay()
 

consensus/replay_test.go

@@ -87,7 +87,7 @@ func sendTxs(cs *ConsensusState, ctx context.Context) {
 			return
 		default:
 			tx := []byte{byte(i)}
-			cs.mempool.CheckTx(tx, nil)
+			assertMempool(cs.txNotifier).CheckTx(tx, nil)
 			i++
 		}
 	}

consensus/state.go

@@ -57,6 +57,16 @@ func (ti *timeoutInfo) String() string {
 	return fmt.Sprintf("%v ; %d/%d %v", ti.Duration, ti.Height, ti.Round, ti.Step)
 }
 
+// interface to the mempool
+type txNotifier interface {
+	TxsAvailable() <-chan struct{}
+}
+
+// interface to the evidence pool
+type evidencePool interface {
+	AddEvidence(types.Evidence) error
+}
+
 // ConsensusState handles execution of the consensus algorithm.
 // It processes votes and proposals, and upon reaching agreement,
 // commits blocks to the chain and executes them against the application.
@@ -68,11 +78,18 @@ type ConsensusState struct {
 	config        *cfg.ConsensusConfig
 	privValidator types.PrivValidator // for signing votes
 
-	// services for creating and executing blocks
-	blockExec  *sm.BlockExecutor
+	// store blocks and commits
 	blockStore sm.BlockStore
-	mempool    sm.Mempool
-	evpool     sm.EvidencePool
+
+	// create and execute blocks
+	blockExec *sm.BlockExecutor
+
+	// notify us if txs are available
+	txNotifier txNotifier
+
+	// add evidence to the pool
+	// when it's detected
+	evpool evidencePool
 
 	// internal state
 	mtx sync.RWMutex
@@ -128,15 +145,15 @@ func NewConsensusState(
 	state sm.State,
 	blockExec *sm.BlockExecutor,
 	blockStore sm.BlockStore,
-	mempool sm.Mempool,
-	evpool sm.EvidencePool,
+	txNotifier txNotifier,
+	evpool evidencePool,
 	options ...StateOption,
 ) *ConsensusState {
 	cs := &ConsensusState{
 		config:           config,
 		blockExec:        blockExec,
 		blockStore:       blockStore,
-		mempool:          mempool,
+		txNotifier:       txNotifier,
 		peerMsgQueue:     make(chan msgInfo, msgQueueSize),
 		internalMsgQueue: make(chan msgInfo, msgQueueSize),
 		timeoutTicker:    NewTimeoutTicker(),
@@ -484,7 +501,7 @@ func (cs *ConsensusState) updateToState(state sm.State) {
 	// If state isn't further out than cs.state, just ignore.
 	// This happens when SwitchToConsensus() is called in the reactor.
 	// We don't want to reset e.g. the Votes, but we still want to
-	// signal the new round step, because other services (eg. mempool)
+	// signal the new round step, because other services (eg. txNotifier)
 	// depend on having an up-to-date peer state!
 	if !cs.state.IsEmpty() && (state.LastBlockHeight <= cs.state.LastBlockHeight) {
 		cs.Logger.Info("Ignoring updateToState()", "newHeight", state.LastBlockHeight+1, "oldHeight", cs.state.LastBlockHeight+1)
@@ -599,7 +616,7 @@ func (cs *ConsensusState) receiveRoutine(maxSteps int) {
 		var mi msgInfo
 
 		select {
-		case <-cs.mempool.TxsAvailable():
+		case <-cs.txNotifier.TxsAvailable():
 			cs.handleTxsAvailable()
 		case mi = <-cs.peerMsgQueue:
 			cs.wal.Write(mi)
@@ -921,20 +938,8 @@ func (cs *ConsensusState) createProposalBlock() (block *types.Block, blockParts
 		return
 	}
 
-	maxBytes := cs.state.ConsensusParams.BlockSize.MaxBytes
-	maxGas := cs.state.ConsensusParams.BlockSize.MaxGas
-	// bound evidence to 1/10th of the block
-	evidence := cs.evpool.PendingEvidence(types.MaxEvidenceBytesPerBlock(maxBytes))
-	// Mempool validated transactions
-	txs := cs.mempool.ReapMaxBytesMaxGas(types.MaxDataBytes(
-		maxBytes,
-		cs.state.Validators.Size(),
-		len(evidence),
-	), maxGas)
 	proposerAddr := cs.privValidator.GetPubKey().Address()
-	block, parts := cs.state.MakeBlock(cs.Height, txs, commit, evidence, proposerAddr)
-
-	return block, parts
+	return cs.blockExec.CreateProposalBlock(cs.Height, cs.state, commit, proposerAddr)
 }
 
 // Enter: `timeoutPropose` after entering Propose.

evidence/pool.go

@@ -57,10 +57,10 @@ func (evpool *EvidencePool) PriorityEvidence() []types.Evidence {
 	return evpool.evidenceStore.PriorityEvidence()
 }
 
-// PendingEvidence returns uncommitted evidence up to maxBytes.
-// If maxBytes is -1, all evidence is returned.
-func (evpool *EvidencePool) PendingEvidence(maxBytes int64) []types.Evidence {
-	return evpool.evidenceStore.PendingEvidence(maxBytes)
+// PendingEvidence returns up to maxNum uncommitted evidence.
+// If maxNum is -1, all evidence is returned.
+func (evpool *EvidencePool) PendingEvidence(maxNum int64) []types.Evidence {
+	return evpool.evidenceStore.PendingEvidence(maxNum)
 }
 
 // State returns the current state of the evpool.

evidence/store.go

@@ -86,26 +86,26 @@ func (store *EvidenceStore) PriorityEvidence() (evidence []types.Evidence) {
 	return l
 }
 
-// PendingEvidence returns known uncommitted evidence up to maxBytes.
-// If maxBytes is -1, all evidence is returned.
-func (store *EvidenceStore) PendingEvidence(maxBytes int64) (evidence []types.Evidence) {
-	return store.listEvidence(baseKeyPending, maxBytes)
+// PendingEvidence returns up to maxNum known, uncommitted evidence.
+// If maxNum is -1, all evidence is returned.
+func (store *EvidenceStore) PendingEvidence(maxNum int64) (evidence []types.Evidence) {
+	return store.listEvidence(baseKeyPending, maxNum)
 }
 
-// listEvidence lists the evidence for the given prefix key up to maxBytes.
+// listEvidence lists up to maxNum pieces of evidence for the given prefix key.
 // It is wrapped by PriorityEvidence and PendingEvidence for convenience.
-// If maxBytes is -1, there's no cap on the size of returned evidence.
-func (store *EvidenceStore) listEvidence(prefixKey string, maxBytes int64) (evidence []types.Evidence) {
-	var bytes int64
+// If maxNum is -1, there's no cap on the size of returned evidence.
+func (store *EvidenceStore) listEvidence(prefixKey string, maxNum int64) (evidence []types.Evidence) {
+	var count int64
 	iter := dbm.IteratePrefix(store.db, []byte(prefixKey))
 	defer iter.Close()
 	for ; iter.Valid(); iter.Next() {
 		val := iter.Value()
 
-		if maxBytes > 0 && bytes+int64(len(val)) > maxBytes {
+		if count == maxNum {
 			return evidence
 		}
-		bytes += int64(len(val))
+		count++
 
 		var ei EvidenceInfo
 		err := cdc.UnmarshalBinaryBare(val, &ei)

evidence/wire.go

@@ -13,3 +13,8 @@ func init() {
 	cryptoAmino.RegisterAmino(cdc)
 	types.RegisterEvidences(cdc)
 }
+
+// For testing purposes only
+func RegisterMockEvidences() {
+	types.RegisterMockEvidences(cdc)
+}

node/node_test.go

@@ -15,10 +15,14 @@ import (
 	"github.com/tendermint/tendermint/abci/example/kvstore"
 	cfg "github.com/tendermint/tendermint/config"
 	"github.com/tendermint/tendermint/crypto/ed25519"
+	"github.com/tendermint/tendermint/evidence"
 	cmn "github.com/tendermint/tendermint/libs/common"
+	dbm "github.com/tendermint/tendermint/libs/db"
 	"github.com/tendermint/tendermint/libs/log"
+	mempl "github.com/tendermint/tendermint/mempool"
 	"github.com/tendermint/tendermint/p2p"
 	"github.com/tendermint/tendermint/privval"
+	"github.com/tendermint/tendermint/proxy"
 	sm "github.com/tendermint/tendermint/state"
 	"github.com/tendermint/tendermint/types"
 	tmtime "github.com/tendermint/tendermint/types/time"
@@ -192,3 +196,110 @@ func testFreeAddr(t *testing.T) string {
 
 	return fmt.Sprintf("127.0.0.1:%d", ln.Addr().(*net.TCPAddr).Port)
 }
+
+// create a proposal block using real and full
+// mempool and evidence pool and validate it.
+func TestCreateProposalBlock(t *testing.T) {
+	config := cfg.ResetTestRoot("node_create_proposal")
+	cc := proxy.NewLocalClientCreator(kvstore.NewKVStoreApplication())
+	proxyApp := proxy.NewAppConns(cc)
+	err := proxyApp.Start()
+	require.Nil(t, err)
+	defer proxyApp.Stop()
+
+	logger := log.TestingLogger()
+
+	var height int64 = 1
+	state, stateDB := state(1, height)
+	maxBytes := 16384
+	state.ConsensusParams.BlockSize.MaxBytes = int64(maxBytes)
+	proposerAddr, _ := state.Validators.GetByIndex(0)
+
+	// Make Mempool
+	memplMetrics := mempl.PrometheusMetrics("node_test")
+	mempool := mempl.NewMempool(
+		config.Mempool,
+		proxyApp.Mempool(),
+		state.LastBlockHeight,
+		mempl.WithMetrics(memplMetrics),
+		mempl.WithPreCheck(sm.TxPreCheck(state)),
+		mempl.WithPostCheck(sm.TxPostCheck(state)),
+	)
+	mempool.SetLogger(logger)
+
+	// Make EvidencePool
+	types.RegisterMockEvidencesGlobal()
+	evidence.RegisterMockEvidences()
+	evidenceDB := dbm.NewMemDB()
+	evidenceStore := evidence.NewEvidenceStore(evidenceDB)
+	evidencePool := evidence.NewEvidencePool(stateDB, evidenceStore)
+	evidencePool.SetLogger(logger)
+
+	// fill the evidence pool with more evidence
+	// than can fit in a block
+	minEvSize := 12
+	numEv := (maxBytes / types.MaxEvidenceBytesDenominator) / minEvSize
+	for i := 0; i < numEv; i++ {
+		ev := types.NewMockRandomGoodEvidence(1, proposerAddr, cmn.RandBytes(minEvSize))
+		err := evidencePool.AddEvidence(ev)
+		assert.NoError(t, err)
+	}
+
+	// fill the mempool with more txs
+	// than can fit in a block
+	txLength := 1000
+	for i := 0; i < maxBytes/txLength; i++ {
+		tx := cmn.RandBytes(txLength)
+		err := mempool.CheckTx(tx, nil)
+		assert.NoError(t, err)
+	}
+
+	blockExec := sm.NewBlockExecutor(
+		stateDB,
+		logger,
+		proxyApp.Consensus(),
+		mempool,
+		evidencePool,
+	)
+
+	commit := &types.Commit{}
+	block, _ := blockExec.CreateProposalBlock(
+		height,
+		state, commit,
+		proposerAddr,
+	)
+
+	err = blockExec.ValidateBlock(state, block)
+	assert.NoError(t, err)
+
+}
+
+func state(nVals int, height int64) (sm.State, dbm.DB) {
+	vals := make([]types.GenesisValidator, nVals)
+	for i := 0; i < nVals; i++ {
+		secret := []byte(fmt.Sprintf("test%d", i))
+		pk := ed25519.GenPrivKeyFromSecret(secret)
+		vals[i] = types.GenesisValidator{
+			pk.PubKey().Address(),
+			pk.PubKey(),
+			1000,
+			fmt.Sprintf("test%d", i),
+		}
+	}
+	s, _ := sm.MakeGenesisState(&types.GenesisDoc{
+		ChainID:    "test-chain",
+		Validators: vals,
+		AppHash:    nil,
+	})
+
+	// save validators to db for 2 heights
+	stateDB := dbm.NewMemDB()
+	sm.SaveState(stateDB, s)
+
+	for i := 1; i < int(height); i++ {
+		s.LastBlockHeight++
+		s.LastValidators = s.Validators.Copy()
+		sm.SaveState(stateDB, s)
+	}
+	return s, stateDB
+}

state/execution.go

@@ -29,7 +29,8 @@ type BlockExecutor struct {
 	// events
 	eventBus types.BlockEventPublisher
 
-	// update these with block results after commit
+	// manage the mempool lock during commit
+	// and update both with block results after commit.
 	mempool Mempool
 	evpool  EvidencePool
 
@@ -73,6 +74,31 @@ func (blockExec *BlockExecutor) SetEventBus(eventBus types.BlockEventPublisher)
 	blockExec.eventBus = eventBus
 }
 
+// CreateProposalBlock calls state.MakeBlock with evidence from the evpool
+// and txs from the mempool. The max bytes must be big enough to fit the commit.
+// Up to 1/10th of the block space is allcoated for maximum sized evidence.
+// The rest is given to txs, up to the max gas.
+func (blockExec *BlockExecutor) CreateProposalBlock(
+	height int64,
+	state State, commit *types.Commit,
+	proposerAddr []byte,
+) (*types.Block, *types.PartSet) {
+
+	maxBytes := state.ConsensusParams.BlockSize.MaxBytes
+	maxGas := state.ConsensusParams.BlockSize.MaxGas
+
+	// Fetch a limited amount of valid evidence
+	maxNumEvidence, _ := types.MaxEvidencePerBlock(maxBytes)
+	evidence := blockExec.evpool.PendingEvidence(maxNumEvidence)
+
+	// Fetch a limited amount of valid txs
+	maxDataBytes := types.MaxDataBytes(maxBytes, state.Validators.Size(), len(evidence))
+	txs := blockExec.mempool.ReapMaxBytesMaxGas(maxDataBytes, maxGas)
+
+	return state.MakeBlock(height, txs, commit, evidence, proposerAddr)
+
+}
+
 // ValidateBlock validates the given block against the given state.
 // If the block is invalid, it returns an error.
 // Validation does not mutate state, but does require historical information from the stateDB,

state/validation.go

@@ -133,10 +133,11 @@ func validateBlock(stateDB dbm.DB, state State, block *types.Block) error {
 	}
 
 	// Limit the amount of evidence
-	maxEvidenceBytes := types.MaxEvidenceBytesPerBlock(state.ConsensusParams.BlockSize.MaxBytes)
-	evidenceBytes := int64(len(block.Evidence.Evidence)) * types.MaxEvidenceBytes
-	if evidenceBytes > maxEvidenceBytes {
-		return types.NewErrEvidenceOverflow(maxEvidenceBytes, evidenceBytes)
+	maxNumEvidence, _ := types.MaxEvidencePerBlock(state.ConsensusParams.BlockSize.MaxBytes)
+	numEvidence := int64(len(block.Evidence.Evidence))
+	if numEvidence > maxNumEvidence {
+		return types.NewErrEvidenceOverflow(maxNumEvidence, numEvidence)
+
 	}
 
 	// Validate all evidence.

state/validation_test.go

@@ -109,10 +109,9 @@ func TestValidateBlockEvidence(t *testing.T) {
 
 	// A block with too much evidence fails.
 	maxBlockSize := state.ConsensusParams.BlockSize.MaxBytes
-	maxEvidenceBytes := types.MaxEvidenceBytesPerBlock(maxBlockSize)
-	maxEvidence := maxEvidenceBytes / types.MaxEvidenceBytes
-	require.True(t, maxEvidence > 2)
-	for i := int64(0); i < maxEvidence; i++ {
+	maxNumEvidence, _ := types.MaxEvidencePerBlock(maxBlockSize)
+	require.True(t, maxNumEvidence > 2)
+	for i := int64(0); i < maxNumEvidence; i++ {
 		block.Evidence.Evidence = append(block.Evidence.Evidence, goodEvidence)
 	}
 	block.EvidenceHash = block.Evidence.Hash()

types/block.go

@@ -322,16 +322,17 @@ func MaxDataBytes(maxBytes int64, valsCount, evidenceCount int) int64 {
 }
 
 // MaxDataBytesUnknownEvidence returns the maximum size of block's data when
-// evidence count is unknown. MaxEvidenceBytesPerBlock will be used as the size
+// evidence count is unknown. MaxEvidencePerBlock will be used for the size
 // of evidence.
 //
 // XXX: Panics on negative result.
 func MaxDataBytesUnknownEvidence(maxBytes int64, valsCount int) int64 {
+	_, maxEvidenceBytes := MaxEvidencePerBlock(maxBytes)
 	maxDataBytes := maxBytes -
 		MaxAminoOverheadForBlock -
 		MaxHeaderBytes -
 		int64(valsCount)*MaxVoteBytes -
-		MaxEvidenceBytesPerBlock(maxBytes)
+		maxEvidenceBytes
 
 	if maxDataBytes < 0 {
 		panic(fmt.Sprintf(

types/evidence.go

@@ -36,8 +36,8 @@ func (err *ErrEvidenceInvalid) Error() string {
 
 // ErrEvidenceOverflow is for when there is too much evidence in a block.
 type ErrEvidenceOverflow struct {
-	MaxBytes int64
-	GotBytes int64
+	MaxNum int64
+	GotNum int64
 }
 
 // NewErrEvidenceOverflow returns a new ErrEvidenceOverflow where got > max.
@@ -47,7 +47,7 @@ func NewErrEvidenceOverflow(max, got int64) *ErrEvidenceOverflow {
 
 // Error returns a string representation of the error.
 func (err *ErrEvidenceOverflow) Error() string {
-	return fmt.Sprintf("Too much evidence: Max %d bytes, got %d bytes", err.MaxBytes, err.GotBytes)
+	return fmt.Sprintf("Too much evidence: Max %d, got %d", err.MaxNum, err.GotNum)
 }
 
 //-------------------------------------------
@@ -72,13 +72,23 @@ func RegisterEvidences(cdc *amino.Codec) {
 
 func RegisterMockEvidences(cdc *amino.Codec) {
 	cdc.RegisterConcrete(MockGoodEvidence{}, "tendermint/MockGoodEvidence", nil)
+	cdc.RegisterConcrete(MockRandomGoodEvidence{}, "tendermint/MockRandomGoodEvidence", nil)
 	cdc.RegisterConcrete(MockBadEvidence{}, "tendermint/MockBadEvidence", nil)
 }
 
-// MaxEvidenceBytesPerBlock returns the maximum evidence size per block -
-// 1/10th of the maximum block size.
-func MaxEvidenceBytesPerBlock(blockMaxBytes int64) int64 {
-	return blockMaxBytes / 10
+const (
+	MaxEvidenceBytesDenominator = 10
+)
+
+// MaxEvidencePerBlock returns the maximum number of evidences
+// allowed in the block and their maximum total size (limitted to 1/10th
+// of the maximum block size).
+// TODO: change to a constant, or to a fraction of the validator set size.
+// See https://github.com/tendermint/tendermint/issues/2590
+func MaxEvidencePerBlock(blockMaxBytes int64) (int64, int64) {
+	maxBytes := blockMaxBytes / MaxEvidenceBytesDenominator
+	maxNum := maxBytes / MaxEvidenceBytes
+	return maxNum, maxBytes
 }
 
 //-------------------------------------------
@@ -193,6 +203,25 @@ func (dve *DuplicateVoteEvidence) ValidateBasic() error {
 
 //-----------------------------------------------------------------
 
+// UNSTABLE
+type MockRandomGoodEvidence struct {
+	MockGoodEvidence
+	randBytes []byte
+}
+
+var _ Evidence = &MockRandomGoodEvidence{}
+
+// UNSTABLE
+func NewMockRandomGoodEvidence(height int64, address []byte, randBytes []byte) MockRandomGoodEvidence {
+	return MockRandomGoodEvidence{
+		MockGoodEvidence{height, address}, randBytes,
+	}
+}
+
+func (e MockRandomGoodEvidence) Hash() []byte {
+	return []byte(fmt.Sprintf("%d-%x", e.Height_, e.randBytes))
+}
+
 // UNSTABLE
 type MockGoodEvidence struct {
 	Height_  int64

types/wire.go

@@ -20,3 +20,8 @@ func RegisterBlockAmino(cdc *amino.Codec) {
 func GetCodec() *amino.Codec {
 	return cdc
 }
+
+// For testing purposes only
+func RegisterMockEvidencesGlobal() {
+	RegisterMockEvidences(cdc)
+}