neo-go/pkg/core/notary_test.go

package core

import (
	"bytes"
	"errors"
	"fmt"
	"math/rand"
	"path"
	"sync"
	"testing"
	"time"

	"github.com/nspcc-dev/neo-go/internal/testchain"
	"github.com/nspcc-dev/neo-go/pkg/config"
	"github.com/nspcc-dev/neo-go/pkg/config/netmode"
	"github.com/nspcc-dev/neo-go/pkg/core/block"
	"github.com/nspcc-dev/neo-go/pkg/core/blockchainer"
	"github.com/nspcc-dev/neo-go/pkg/core/mempool"
	"github.com/nspcc-dev/neo-go/pkg/core/native"
	"github.com/nspcc-dev/neo-go/pkg/core/transaction"
	"github.com/nspcc-dev/neo-go/pkg/crypto/hash"
	"github.com/nspcc-dev/neo-go/pkg/crypto/keys"
	"github.com/nspcc-dev/neo-go/pkg/io"
	"github.com/nspcc-dev/neo-go/pkg/network/payload"
	"github.com/nspcc-dev/neo-go/pkg/services/notary"
	"github.com/nspcc-dev/neo-go/pkg/smartcontract"
	"github.com/nspcc-dev/neo-go/pkg/smartcontract/trigger"
	"github.com/nspcc-dev/neo-go/pkg/util"
	"github.com/nspcc-dev/neo-go/pkg/vm/opcode"
	"github.com/nspcc-dev/neo-go/pkg/wallet"
	"github.com/stretchr/testify/require"
	"go.uber.org/zap/zaptest"
)

const notaryModulePath = "../services/notary/"

func getTestNotary(t *testing.T, bc *Blockchain, walletPath, pass string, onTx func(tx *transaction.Transaction) error) (*wallet.Account, *notary.Notary, *mempool.Pool) {
	mainCfg := config.P2PNotary{
		Enabled: true,
		UnlockWallet: config.Wallet{
			Path:     path.Join(notaryModulePath, walletPath),
			Password: pass,
		},
	}
	cfg := notary.Config{
		MainCfg: mainCfg,
		Chain:   bc,
		Log:     zaptest.NewLogger(t),
	}
	mp := mempool.New(10, 1, true)
	ntr, err := notary.NewNotary(cfg, mp, onTx)
	require.NoError(t, err)

	w, err := wallet.NewWalletFromFile(path.Join(notaryModulePath, walletPath))
	require.NoError(t, err)
	require.NoError(t, w.Accounts[0].Decrypt(pass))
	return w.Accounts[0], ntr, mp
}

func TestNotary(t *testing.T) {
	bc := newTestChain(t)
	var (
		nonce           uint32
		nvbDiffFallback uint32 = 20
	)

	mtx := sync.RWMutex{}
	completedTxes := make(map[util.Uint256]*transaction.Transaction)
	var unluckies []*payload.P2PNotaryRequest
	var (
		finalizeWithError bool
		choosy            bool
	)
	onTransaction := func(tx *transaction.Transaction) error {
		mtx.Lock()
		defer mtx.Unlock()
		if !choosy {
			if completedTxes[tx.Hash()] != nil {
				panic("transaction was completed twice")
			}
			if finalizeWithError {
				return errors.New("error while finalizing transaction")
			}
			completedTxes[tx.Hash()] = tx
			return nil
		}
		for _, unl := range unluckies {
			if tx.Hash().Equals(unl.FallbackTransaction.Hash()) {
				return errors.New("error while finalizing transaction")
			}
		}
		completedTxes[tx.Hash()] = tx
		return nil
	}

	acc1, ntr1, mp1 := getTestNotary(t, bc, "./testdata/notary1.json", "one", onTransaction)
	acc2, _, _ := getTestNotary(t, bc, "./testdata/notary2.json", "two", onTransaction)
	randomAcc, err := keys.NewPrivateKey()
	require.NoError(t, err)

	bc.SetNotary(ntr1)
	bc.RegisterPostBlock(func(bc blockchainer.Blockchainer, pool *mempool.Pool, b *block.Block) {
		ntr1.PostPersist()
	})

	notaryNodes := keys.PublicKeys{acc1.PrivateKey().PublicKey(), acc2.PrivateKey().PublicKey()}
	bc.setNodesByRole(t, true, native.RoleP2PNotary, notaryNodes)

	createFallbackTx := func(requester *wallet.Account, mainTx *transaction.Transaction, nvbIncrement ...uint32) *transaction.Transaction {
		fallback := transaction.New(testchain.Network(), []byte{byte(opcode.RET)}, 2000_0000)
		fallback.Nonce = nonce
		nonce++
		fallback.SystemFee = 1_0000_0000
		fallback.ValidUntilBlock = bc.BlockHeight() + 50
		fallback.Signers = []transaction.Signer{
			{
				Account: bc.GetNotaryContractScriptHash(),
				Scopes:  transaction.None,
			},
			{
				Account: requester.PrivateKey().PublicKey().GetScriptHash(),
				Scopes:  transaction.None,
			},
		}
		nvb := bc.BlockHeight() + nvbDiffFallback
		if len(nvbIncrement) != 0 {
			nvb += nvbIncrement[0]
		}
		fallback.Attributes = []transaction.Attribute{
			{
				Type:  transaction.NotaryAssistedT,
				Value: &transaction.NotaryAssisted{NKeys: 0},
			},
			{
				Type:  transaction.NotValidBeforeT,
				Value: &transaction.NotValidBefore{Height: nvb},
			},
			{
				Type:  transaction.ConflictsT,
				Value: &transaction.Conflicts{Hash: mainTx.Hash()},
			},
		}
		fallback.Scripts = []transaction.Witness{
			{
				InvocationScript:   append([]byte{byte(opcode.PUSHDATA1), 64}, make([]byte, 64)...),
				VerificationScript: []byte{},
			},
		}
		requester.SignTx(fallback)
		return fallback
	}

	createStandardRequest := func(requesters []*wallet.Account, NVBincrements ...uint32) []*payload.P2PNotaryRequest {
		mainTx := *transaction.New(testchain.Network(), []byte{byte(opcode.RET)}, 11000000)
		mainTx.Nonce = nonce
		nonce++
		mainTx.SystemFee = 100000000
		mainTx.ValidUntilBlock = bc.BlockHeight() + 2*nvbDiffFallback
		signers := make([]transaction.Signer, len(requesters)+1)
		for i := range requesters {
			signers[i] = transaction.Signer{
				Account: requesters[i].PrivateKey().PublicKey().GetScriptHash(),
				Scopes:  transaction.None,
			}
		}
		signers[len(signers)-1] = transaction.Signer{
			Account: bc.GetNotaryContractScriptHash(),
			Scopes:  transaction.None,
		}
		mainTx.Signers = signers
		mainTx.Attributes = []transaction.Attribute{
			{
				Type:  transaction.NotaryAssistedT,
				Value: &transaction.NotaryAssisted{NKeys: uint8(len(requesters))},
			},
		}
		payloads := make([]*payload.P2PNotaryRequest, len(requesters))
		for i := range payloads {
			cp := mainTx
			main := &cp
			scripts := make([]transaction.Witness, len(requesters)+1)
			for j := range requesters {
				scripts[j].VerificationScript = requesters[j].PrivateKey().PublicKey().GetVerificationScript()
			}
			scripts[i].InvocationScript = append([]byte{byte(opcode.PUSHDATA1), 64}, requesters[i].PrivateKey().Sign(main.GetSignedPart())...)
			main.Scripts = scripts

			_ = main.Size() // for size update test

			var fallback *transaction.Transaction
			if len(NVBincrements) == len(requesters) {
				fallback = createFallbackTx(requesters[i], main, NVBincrements[i])
			} else {
				fallback = createFallbackTx(requesters[i], main)
			}

			_ = fallback.Size() // for size update test

			payloads[i] = &payload.P2PNotaryRequest{
				MainTransaction:     main,
				FallbackTransaction: fallback,
				Network:             netmode.UnitTestNet,
			}
		}
		return payloads
	}
	createMultisigRequest := func(m int, requesters []*wallet.Account) []*payload.P2PNotaryRequest {
		mainTx := *transaction.New(testchain.Network(), []byte{byte(opcode.RET)}, 11000000)
		mainTx.Nonce = nonce
		nonce++
		mainTx.SystemFee = 100000000
		mainTx.ValidUntilBlock = bc.BlockHeight() + 2*nvbDiffFallback
		pubs := make(keys.PublicKeys, len(requesters))
		for i, r := range requesters {
			pubs[i] = r.PrivateKey().PublicKey()
		}
		script, err := smartcontract.CreateMultiSigRedeemScript(m, pubs)
		require.NoError(t, err)
		mainTx.Signers = []transaction.Signer{
			{
				Account: hash.Hash160(script),
				Scopes:  transaction.None,
			},
			{
				Account: bc.GetNotaryContractScriptHash(),
				Scopes:  transaction.None,
			},
		}
		mainTx.Attributes = []transaction.Attribute{
			{
				Type:  transaction.NotaryAssistedT,
				Value: &transaction.NotaryAssisted{NKeys: uint8(len(requesters))},
			},
		}

		payloads := make([]*payload.P2PNotaryRequest, len(requesters))
		// we'll collect only m signatures out of n (so only m payloads are needed), but let's create payloads for all requesters (for the next tests)
		for i := range payloads {
			cp := mainTx
			main := &cp
			main.Scripts = []transaction.Witness{
				{
					InvocationScript:   append([]byte{byte(opcode.PUSHDATA1), 64}, requesters[i].PrivateKey().Sign(main.GetSignedPart())...),
					VerificationScript: script,
				},
				{}, // empty Notary witness
			}
			fallback := createFallbackTx(requesters[i], main)
			payloads[i] = &payload.P2PNotaryRequest{
				MainTransaction:     main,
				FallbackTransaction: fallback,
				Network:             netmode.UnitTestNet,
			}
		}
		return payloads
	}
	checkSigTx := func(t *testing.T, requests []*payload.P2PNotaryRequest, sentCount int, shouldComplete bool) {
		nKeys := len(requests)
		completedTx := completedTxes[requests[0].MainTransaction.Hash()]
		if sentCount == nKeys && shouldComplete {
			require.NotNil(t, completedTx, errors.New("main transaction expected to be completed"))
			require.Equal(t, nKeys+1, len(completedTx.Signers))
			require.Equal(t, nKeys+1, len(completedTx.Scripts))

			// check that tx size was updated
			require.Equal(t, io.GetVarSize(completedTx), completedTx.Size())

			interopCtx := bc.newInteropContext(trigger.Verification, bc.dao, nil, completedTx)
			for i, req := range requests {
				require.Equal(t, req.MainTransaction.Scripts[i], completedTx.Scripts[i])
				_, err := bc.verifyHashAgainstScript(completedTx.Signers[i].Account, &completedTx.Scripts[i], interopCtx, -1)
				require.NoError(t, err)
			}
			require.Equal(t, transaction.Witness{
				InvocationScript:   append([]byte{byte(opcode.PUSHDATA1), 64}, acc1.PrivateKey().Sign(requests[0].MainTransaction.GetSignedPart())...),
				VerificationScript: []byte{},
			}, completedTx.Scripts[nKeys])
		} else {
			require.Nil(t, completedTx, fmt.Errorf("main transaction shouldn't be completed: sent %d out of %d requests", sentCount, nKeys))
		}
	}
	checkMultisigTx := func(t *testing.T, nSigs int, requests []*payload.P2PNotaryRequest, sentCount int, shouldComplete bool) {
		completedTx := completedTxes[requests[0].MainTransaction.Hash()]
		if sentCount >= nSigs && shouldComplete {
			require.NotNil(t, completedTx, errors.New("main transaction expected to be completed"))
			require.Equal(t, 2, len(completedTx.Signers))
			require.Equal(t, 2, len(completedTx.Scripts))
			interopCtx := bc.newInteropContext(trigger.Verification, bc.dao, nil, completedTx)
			_, err := bc.verifyHashAgainstScript(completedTx.Signers[0].Account, &completedTx.Scripts[0], interopCtx, -1)
			require.NoError(t, err)
			require.Equal(t, transaction.Witness{
				InvocationScript:   append([]byte{byte(opcode.PUSHDATA1), 64}, acc1.PrivateKey().Sign(requests[0].MainTransaction.GetSignedPart())...),
				VerificationScript: []byte{},
			}, completedTx.Scripts[1])
			// check that only nSigs out of nKeys signatures are presented in the invocation script
			for i, req := range requests[:nSigs] {
				require.True(t, bytes.Contains(completedTx.Scripts[0].InvocationScript, req.MainTransaction.Scripts[0].InvocationScript), fmt.Errorf("signature from extra request #%d shouldn't be presented in the main tx", i))
			}
			// the rest (nKeys-nSigs) out of nKeys shouldn't be presented in the invocation script
			for i, req := range requests[nSigs:] {
				require.False(t, bytes.Contains(completedTx.Scripts[0].InvocationScript, req.MainTransaction.Scripts[0].InvocationScript), fmt.Errorf("signature from extra request #%d shouldn't be presented in the main tx", i))
			}
		} else {
			require.Nil(t, completedTx, fmt.Errorf("main transaction shouldn't be completed: sent %d out of %d requests", sentCount, nSigs))
		}
	}
	checkFallbackTxs := func(t *testing.T, requests []*payload.P2PNotaryRequest, shouldComplete bool) {
		for i, req := range requests {
			completedTx := completedTxes[req.FallbackTransaction.Hash()]
			if shouldComplete {
				require.NotNil(t, completedTx, fmt.Errorf("fallback transaction for request #%d expected to be completed", i))
				require.Equal(t, 2, len(completedTx.Signers))
				require.Equal(t, 2, len(completedTx.Scripts))
				require.Equal(t, transaction.Witness{
					InvocationScript:   append([]byte{byte(opcode.PUSHDATA1), 64}, acc1.PrivateKey().Sign(req.FallbackTransaction.GetSignedPart())...),
					VerificationScript: []byte{},
				}, completedTx.Scripts[0])

				// check that tx size was updated
				require.Equal(t, io.GetVarSize(completedTx), completedTx.Size())

				interopCtx := bc.newInteropContext(trigger.Verification, bc.dao, nil, completedTx)
				_, err := bc.verifyHashAgainstScript(completedTx.Signers[1].Account, &completedTx.Scripts[1], interopCtx, -1)
				require.NoError(t, err)
			} else {
				require.Nil(t, completedTx, fmt.Errorf("fallback transaction for request #%d shouldn't be completed", i))
			}
		}
	}
	checkCompleteStandardRequest := func(t *testing.T, nKeys int, shouldComplete bool, nvbIncrements ...uint32) []*payload.P2PNotaryRequest {
		requesters := make([]*wallet.Account, nKeys)
		for i := range requesters {
			requesters[i], _ = wallet.NewAccount()
		}

		requests := createStandardRequest(requesters, nvbIncrements...)
		sendOrder := make([]int, nKeys)
		for i := range sendOrder {
			sendOrder[i] = i
		}
		rand.Shuffle(nKeys, func(i, j int) {
			sendOrder[j], sendOrder[i] = sendOrder[i], sendOrder[j]
		})
		for i := range requests {
			ntr1.OnNewRequest(requests[sendOrder[i]])
			checkSigTx(t, requests, i+1, shouldComplete)
			completedCount := len(completedTxes)

			// check that the same request won't be processed twice
			ntr1.OnNewRequest(requests[sendOrder[i]])
			checkSigTx(t, requests, i+1, shouldComplete)
			require.Equal(t, completedCount, len(completedTxes))
		}
		return requests
	}
	checkCompleteMultisigRequest := func(t *testing.T, nSigs int, nKeys int, shouldComplete bool) []*payload.P2PNotaryRequest {
		requesters := make([]*wallet.Account, nKeys)
		for i := range requesters {
			requesters[i], _ = wallet.NewAccount()
		}
		requests := createMultisigRequest(nSigs, requesters)
		sendOrder := make([]int, nKeys)
		for i := range sendOrder {
			sendOrder[i] = i
		}
		rand.Shuffle(nKeys, func(i, j int) {
			sendOrder[j], sendOrder[i] = sendOrder[i], sendOrder[j]
		})

		var submittedRequests []*payload.P2PNotaryRequest
		// sent only nSigs (m out of n) requests - it should be enough to complete min tx
		for i := 0; i < nSigs; i++ {
			submittedRequests = append(submittedRequests, requests[sendOrder[i]])

			ntr1.OnNewRequest(requests[sendOrder[i]])
			checkMultisigTx(t, nSigs, submittedRequests, i+1, shouldComplete)

			// check that the same request won't be processed twice
			ntr1.OnNewRequest(requests[sendOrder[i]])
			checkMultisigTx(t, nSigs, submittedRequests, i+1, shouldComplete)
		}

		// sent the rest (n-m) out of n requests: main tx is already collected, so only fallbacks should be applied
		completedCount := len(completedTxes)
		for i := nSigs; i < nKeys; i++ {
			submittedRequests = append(submittedRequests, requests[sendOrder[i]])

			ntr1.OnNewRequest(requests[sendOrder[i]])
			checkMultisigTx(t, nSigs, submittedRequests, i+1, shouldComplete)
			require.Equal(t, completedCount, len(completedTxes))
		}

		return submittedRequests
	}

	// OnNewRequest: missing account
	ntr1.UpdateNotaryNodes(keys.PublicKeys{randomAcc.PublicKey()})
	r := checkCompleteStandardRequest(t, 1, false)
	checkFallbackTxs(t, r, false)
	// set account back for the next tests
	ntr1.UpdateNotaryNodes(keys.PublicKeys{acc1.PrivateKey().PublicKey()})

	// OnNewRequest: signature request
	for _, i := range []int{1, 2, 3, 10} {
		r := checkCompleteStandardRequest(t, i, true)
		checkFallbackTxs(t, r, false)
	}

	// OnNewRequest: multisignature request
	r = checkCompleteMultisigRequest(t, 1, 1, true)
	checkFallbackTxs(t, r, false)
	r = checkCompleteMultisigRequest(t, 1, 2, true)
	checkFallbackTxs(t, r, false)
	r = checkCompleteMultisigRequest(t, 1, 3, true)
	checkFallbackTxs(t, r, false)
	r = checkCompleteMultisigRequest(t, 3, 3, true)
	checkFallbackTxs(t, r, false)
	r = checkCompleteMultisigRequest(t, 3, 4, true)
	checkFallbackTxs(t, r, false)
	r = checkCompleteMultisigRequest(t, 3, 10, true)
	checkFallbackTxs(t, r, false)

	// PostPersist: missing account
	finalizeWithError = true
	r = checkCompleteStandardRequest(t, 1, false)
	checkFallbackTxs(t, r, false)
	finalizeWithError = false
	ntr1.UpdateNotaryNodes(keys.PublicKeys{randomAcc.PublicKey()})
	require.NoError(t, bc.AddBlock(bc.newBlock()))
	checkSigTx(t, r, 1, false)
	checkFallbackTxs(t, r, false)
	// set account back for the next tests
	ntr1.UpdateNotaryNodes(keys.PublicKeys{acc1.PrivateKey().PublicKey()})

	// PostPersist: complete main transaction, signature request
	finalizeWithError = true
	requests := checkCompleteStandardRequest(t, 3, false)
	// check PostPersist with finalisation error
	finalizeWithError = true
	require.NoError(t, bc.AddBlock(bc.newBlock()))
	checkSigTx(t, requests, len(requests), false)
	// check PostPersist without finalisation error
	finalizeWithError = false
	require.NoError(t, bc.AddBlock(bc.newBlock()))
	checkSigTx(t, requests, len(requests), true)

	// PostPersist: complete main transaction, multisignature account
	finalizeWithError = true
	requests = checkCompleteMultisigRequest(t, 3, 4, false)
	checkFallbackTxs(t, requests, false)
	// check PostPersist with finalisation error
	finalizeWithError = true
	require.NoError(t, bc.AddBlock(bc.newBlock()))
	checkMultisigTx(t, 3, requests, len(requests), false)
	checkFallbackTxs(t, requests, false)
	// check PostPersist without finalisation error
	finalizeWithError = false
	require.NoError(t, bc.AddBlock(bc.newBlock()))
	checkMultisigTx(t, 3, requests, len(requests), true)
	checkFallbackTxs(t, requests, false)

	// PostPersist: complete fallback, signature request
	finalizeWithError = true
	requests = checkCompleteStandardRequest(t, 3, false)
	checkFallbackTxs(t, requests, false)
	// make fallbacks valid
	_, err = bc.genBlocks(int(nvbDiffFallback))
	require.NoError(t, err)
	// check PostPersist for valid fallbacks with finalisation error
	require.NoError(t, bc.AddBlock(bc.newBlock()))
	checkSigTx(t, requests, len(requests), false)
	checkFallbackTxs(t, requests, false)
	// check PostPersist for valid fallbacks without finalisation error
	finalizeWithError = false
	require.NoError(t, bc.AddBlock(bc.newBlock()))
	checkSigTx(t, requests, len(requests), false)
	checkFallbackTxs(t, requests, true)

	// PostPersist: complete fallback, multisignature request
	nSigs, nKeys := 3, 5
	// check OnNewRequest with finalization error
	finalizeWithError = true
	requests = checkCompleteMultisigRequest(t, nSigs, nKeys, false)
	checkFallbackTxs(t, requests, false)
	// make fallbacks valid
	_, err = bc.genBlocks(int(nvbDiffFallback))
	require.NoError(t, err)
	// check PostPersist for valid fallbacks with finalisation error
	require.NoError(t, bc.AddBlock(bc.newBlock()))
	checkMultisigTx(t, nSigs, requests, len(requests), false)
	checkFallbackTxs(t, requests, false)
	// check PostPersist for valid fallbacks without finalisation error
	finalizeWithError = false
	require.NoError(t, bc.AddBlock(bc.newBlock()))
	checkMultisigTx(t, nSigs, requests, len(requests), false)
	checkFallbackTxs(t, requests[:nSigs], true)
	// the rest of fallbacks should also be applied even if the main tx was already constructed by the moment they were sent
	checkFallbackTxs(t, requests[nSigs:], true)

	// PostPersist: partial fallbacks completion due to finalisation errors
	finalizeWithError = true
	requests = checkCompleteStandardRequest(t, 5, false)
	checkFallbackTxs(t, requests, false)
	// make fallbacks valid
	_, err = bc.genBlocks(int(nvbDiffFallback))
	require.NoError(t, err)
	// some of fallbacks should fail finalisation
	unluckies = []*payload.P2PNotaryRequest{requests[0], requests[4]}
	lucky := requests[1:4]
	choosy = true
	// check PostPersist for lucky fallbacks
	require.NoError(t, bc.AddBlock(bc.newBlock()))
	checkSigTx(t, requests, len(requests), false)
	checkFallbackTxs(t, lucky, true)
	checkFallbackTxs(t, unluckies, false)
	// reset finalisation function for unlucky fallbacks to finalise without an error
	choosy = false
	finalizeWithError = false
	// check PostPersist for unlucky fallbacks
	require.NoError(t, bc.AddBlock(bc.newBlock()))
	checkSigTx(t, requests, len(requests), false)
	checkFallbackTxs(t, lucky, true)
	checkFallbackTxs(t, unluckies, true)

	// PostPersist: different NVBs
	// check OnNewRequest with finalization error and different NVBs
	finalizeWithError = true
	requests = checkCompleteStandardRequest(t, 5, false, 1, 2, 3, 4, 5)
	checkFallbackTxs(t, requests, false)
	// generate blocks to reach the most earlier fallback's NVB
	_, err = bc.genBlocks(int(nvbDiffFallback))
	require.NoError(t, err)
	// check PostPersist for valid fallbacks without finalisation error
	finalizeWithError = false
	for i := range requests {
		require.NoError(t, bc.AddBlock(bc.newBlock()))
		checkSigTx(t, requests, len(requests), false)
		checkFallbackTxs(t, requests[:i+1], true)
		checkFallbackTxs(t, requests[i+1:], false)
	}

	// OnRequestRemoval: missing account
	// check OnNewRequest with finalization error
	finalizeWithError = true
	requests = checkCompleteStandardRequest(t, 4, false)
	checkFallbackTxs(t, requests, false)
	// make fallbacks valid and remove one fallback
	_, err = bc.genBlocks(int(nvbDiffFallback))
	require.NoError(t, err)
	ntr1.UpdateNotaryNodes(keys.PublicKeys{randomAcc.PublicKey()})
	ntr1.OnRequestRemoval(requests[3])
	// non of the fallbacks should be completed
	finalizeWithError = false
	require.NoError(t, bc.AddBlock(bc.newBlock()))
	checkSigTx(t, requests, len(requests), false)
	checkFallbackTxs(t, requests, false)
	// set account back for the next tests
	ntr1.UpdateNotaryNodes(keys.PublicKeys{acc1.PrivateKey().PublicKey()})

	// OnRequestRemoval: signature request, remove one fallback
	// check OnNewRequest with finalization error
	finalizeWithError = true
	requests = checkCompleteStandardRequest(t, 4, false)
	checkFallbackTxs(t, requests, false)
	// make fallbacks valid and remove one fallback
	_, err = bc.genBlocks(int(nvbDiffFallback))
	require.NoError(t, err)
	unlucky := requests[3]
	ntr1.OnRequestRemoval(unlucky)
	// rest of the fallbacks should be completed
	finalizeWithError = false
	require.NoError(t, bc.AddBlock(bc.newBlock()))
	checkSigTx(t, requests, len(requests), false)
	checkFallbackTxs(t, requests[:3], true)
	require.Nil(t, completedTxes[unlucky.FallbackTransaction.Hash()])

	// OnRequestRemoval: signature request, remove all fallbacks
	finalizeWithError = true
	requests = checkCompleteStandardRequest(t, 4, false)
	// remove all fallbacks
	_, err = bc.genBlocks(int(nvbDiffFallback))
	require.NoError(t, err)
	for i := range requests {
		ntr1.OnRequestRemoval(requests[i])
	}
	// then the whole request should be removed, i.e. there are no completed transactions
	finalizeWithError = false
	require.NoError(t, bc.AddBlock(bc.newBlock()))
	checkSigTx(t, requests, len(requests), false)
	checkFallbackTxs(t, requests, false)

	// OnRequestRemoval: signature request, remove unexisting fallback
	ntr1.OnRequestRemoval(requests[0])
	require.NoError(t, bc.AddBlock(bc.newBlock()))
	checkSigTx(t, requests, len(requests), false)
	checkFallbackTxs(t, requests, false)

	// OnRequestRemoval: multisignature request, remove one fallback
	nSigs, nKeys = 3, 5
	// check OnNewRequest with finalization error
	finalizeWithError = true
	requests = checkCompleteMultisigRequest(t, nSigs, nKeys, false)
	checkMultisigTx(t, nSigs, requests, len(requests), false)
	checkFallbackTxs(t, requests, false)
	// make fallbacks valid and remove the last fallback
	_, err = bc.genBlocks(int(nvbDiffFallback))
	require.NoError(t, err)
	unlucky = requests[nSigs-1]
	ntr1.OnRequestRemoval(unlucky)
	// then (m-1) out of n fallbacks should be completed
	finalizeWithError = false
	require.NoError(t, bc.AddBlock(bc.newBlock()))
	checkMultisigTx(t, nSigs, requests, len(requests), false)
	checkFallbackTxs(t, requests[:nSigs-1], true)
	require.Nil(t, completedTxes[unlucky.FallbackTransaction.Hash()])
	//  the rest (n-(m-1)) out of n fallbacks should also be completed even if main tx has been collected by the moment they were sent
	checkFallbackTxs(t, requests[nSigs:], true)

	// OnRequestRemoval: multisignature request, remove all fallbacks
	finalizeWithError = true
	requests = checkCompleteMultisigRequest(t, nSigs, nKeys, false)
	// make fallbacks valid and then remove all of them
	_, err = bc.genBlocks(int(nvbDiffFallback))
	require.NoError(t, err)
	for i := range requests {
		ntr1.OnRequestRemoval(requests[i])
	}
	// then the whole request should be removed, i.e. there are no completed transactions
	finalizeWithError = false
	require.NoError(t, bc.AddBlock(bc.newBlock()))
	checkMultisigTx(t, nSigs, requests, len(requests), false)
	checkFallbackTxs(t, requests, false)

	// // OnRequestRemoval: multisignature request, remove unexisting fallbac, i.e. there still shouldn't be any completed transactions after this
	ntr1.OnRequestRemoval(requests[0])
	require.NoError(t, bc.AddBlock(bc.newBlock()))
	checkMultisigTx(t, nSigs, requests, len(requests), false)
	checkFallbackTxs(t, requests, false)

	// Subscriptions test
	mp1.RunSubscriptions()
	go ntr1.Run()
	t.Cleanup(func() {
		ntr1.Stop()
		mp1.StopSubscriptions()
	})
	finalizeWithError = false
	requester1, _ := wallet.NewAccount()
	requester2, _ := wallet.NewAccount()
	amount := int64(100_0000_0000)
	feer := NewNotaryFeerStub(bc)
	transferTokenFromMultisigAccountCheckOK(t, bc, bc.GetNotaryContractScriptHash(), bc.contracts.GAS.Hash, amount, requester1.PrivateKey().PublicKey().GetScriptHash(), int64(bc.BlockHeight()+50))
	checkBalanceOf(t, bc, bc.contracts.Notary.Hash, int(amount))
	transferTokenFromMultisigAccountCheckOK(t, bc, bc.GetNotaryContractScriptHash(), bc.contracts.GAS.Hash, amount, requester2.PrivateKey().PublicKey().GetScriptHash(), int64(bc.BlockHeight()+50))
	checkBalanceOf(t, bc, bc.contracts.Notary.Hash, int(2*amount))
	// create request for 2 standard signatures => main tx should be completed after the second request is added to the pool
	requests = createStandardRequest([]*wallet.Account{requester1, requester2})
	require.NoError(t, mp1.Add(requests[0].FallbackTransaction, feer, requests[0]))
	require.NoError(t, mp1.Add(requests[1].FallbackTransaction, feer, requests[1]))
	require.Eventually(t, func() bool {
		mtx.RLock()
		defer mtx.RUnlock()
		return completedTxes[requests[0].MainTransaction.Hash()] != nil
	}, time.Second, time.Millisecond)
	checkFallbackTxs(t, requests, false)
}