feat: add simulation for nft module (#10522)

## Description Add nft module simulation and unit test,refer #9826  --- ### Author Checklist *All items are required. Please add a note to the item if the item is not applicable and please add links to any relevant follow up issues.* I have... - [ ] included the correct [type prefix](https://github.com/commitizen/conventional-commit-types/blob/v3.0.0/index.json) in the PR title - [ ] added `!` to the type prefix if API or client breaking change - [ ] targeted the correct branch (see [PR Targeting](https://github.com/cosmos/cosmos-sdk/blob/master/CONTRIBUTING.md#pr-targeting)) - [ ] provided a link to the relevant issue or specification - [ ] followed the guidelines for [building modules](https://github.com/cosmos/cosmos-sdk/blob/master/docs/building-modules) - [ ] included the necessary unit and integration [tests](https://github.com/cosmos/cosmos-sdk/blob/master/CONTRIBUTING.md#testing) - [ ] added a changelog entry to `CHANGELOG.md` - [ ] included comments for [documenting Go code](https://blog.golang.org/godoc) - [ ] updated the relevant documentation or specification - [ ] reviewed "Files changed" and left comments if necessary - [ ] confirmed all CI checks have passed ### Reviewers Checklist *All items are required. Please add a note if the item is not applicable and please add your handle next to the items reviewed if you only reviewed selected items.* I have... - [ ] confirmed the correct [type prefix](https://github.com/commitizen/conventional-commit-types/blob/v3.0.0/index.json) in the PR title - [ ] confirmed `!` in the type prefix if API or client breaking change - [ ] confirmed all author checklist items have been addressed - [ ] reviewed state machine logic - [ ] reviewed API design and naming - [ ] reviewed documentation is accurate - [ ] reviewed tests and test coverage - [ ] manually tested (if applicable)
2021-11-11 23:44:41 +08:00 · 2021-11-11 23:44:41 +08:00 · ba843a351c
parent b6d416d871
commit ba843a351c
8 changed files with 555 additions and 2 deletions
--- a/simapp/app.go
+++ b/simapp/app.go
@ -391,6 +391,7 @@ func NewSimApp(
 		params.NewAppModule(app.ParamsKeeper),
 		evidence.NewAppModule(app.EvidenceKeeper),
 		authzmodule.NewAppModule(appCodec, app.AuthzKeeper, app.AccountKeeper, app.BankKeeper, app.interfaceRegistry),
+		nftmodule.NewAppModule(appCodec, app.NFTKeeper, app.AccountKeeper, app.BankKeeper, app.interfaceRegistry),
 	)

 	app.sm.RegisterStoreDecoders()
--- a/x/nft/module/module.go
+++ b/x/nft/module/module.go
@ -3,6 +3,7 @@ package nft
 import (
 	"context"
 	"encoding/json"
+	"math/rand"

 	"github.com/gorilla/mux"
 	"github.com/grpc-ecosystem/grpc-gateway/runtime"
@ -15,15 +16,18 @@ import (
 	sdk "github.com/cosmos/cosmos-sdk/types"
 	sdkerrors "github.com/cosmos/cosmos-sdk/types/errors"
 	"github.com/cosmos/cosmos-sdk/types/module"
+	simtypes "github.com/cosmos/cosmos-sdk/types/simulation"

 	"github.com/cosmos/cosmos-sdk/x/nft"
 	"github.com/cosmos/cosmos-sdk/x/nft/client/cli"
 	"github.com/cosmos/cosmos-sdk/x/nft/keeper"
+	"github.com/cosmos/cosmos-sdk/x/nft/simulation"
 )

 var (
-	_ module.AppModule      = AppModule{}
-	_ module.AppModuleBasic = AppModuleBasic{}
+	_ module.AppModule           = AppModule{}
+	_ module.AppModuleBasic      = AppModuleBasic{}
+	_ module.AppModuleSimulation = AppModule{}
 )

 // AppModuleBasic defines the basic application module used by the nft module.
@ -159,3 +163,37 @@ func (am AppModule) BeginBlock(ctx sdk.Context, req abci.RequestBeginBlock) {}
 func (am AppModule) EndBlock(ctx sdk.Context, _ abci.RequestEndBlock) []abci.ValidatorUpdate {
 	return []abci.ValidatorUpdate{}
 }
+
+// ____________________________________________________________________________
+
+// AppModuleSimulation functions
+
+// GenerateGenesisState creates a randomized GenState of the nft module.
+func (AppModule) GenerateGenesisState(simState *module.SimulationState) {
+	simulation.RandomizedGenState(simState)
+}
+
+// ProposalContents returns all the nft content functions used to
+// simulate governance proposals.
+func (am AppModule) ProposalContents(simState module.SimulationState) []simtypes.WeightedProposalContent {
+	return nil
+}
+
+// RandomizedParams creates randomized nft param changes for the simulator.
+func (AppModule) RandomizedParams(r *rand.Rand) []simtypes.ParamChange {
+	return nil
+}
+
+// RegisterStoreDecoder registers a decoder for nft module's types
+func (am AppModule) RegisterStoreDecoder(sdr sdk.StoreDecoderRegistry) {
+	sdr[keeper.StoreKey] = simulation.NewDecodeStore(am.cdc)
+}
+
+// WeightedOperations returns the all the nft module operations with their respective weights.
+func (am AppModule) WeightedOperations(simState module.SimulationState) []simtypes.WeightedOperation {
+	return simulation.WeightedOperations(
+		am.registry,
+		simState.AppParams, simState.Cdc,
+		am.accountKeeper, am.bankKeeper, am.keeper,
+	)
+}
--- a/x/nft/simulation/decoder.go
+++ b/x/nft/simulation/decoder.go
@ -0,0 +1,45 @@
+package simulation
+
+import (
+	"bytes"
+	"fmt"
+
+	"github.com/cosmos/cosmos-sdk/codec"
+	sdk "github.com/cosmos/cosmos-sdk/types"
+	"github.com/cosmos/cosmos-sdk/types/kv"
+	"github.com/cosmos/cosmos-sdk/x/nft"
+	"github.com/cosmos/cosmos-sdk/x/nft/keeper"
+)
+
+// NewDecodeStore returns a decoder function closure that umarshals the KVPair's
+// Value to the corresponding nft type.
+func NewDecodeStore(cdc codec.Codec) func(kvA, kvB kv.Pair) string {
+	return func(kvA, kvB kv.Pair) string {
+		switch {
+		case bytes.Equal(kvA.Key[:1], keeper.ClassKey):
+			var classA, classB nft.Class
+			cdc.MustUnmarshal(kvA.Value, &classA)
+			cdc.MustUnmarshal(kvB.Value, &classB)
+			return fmt.Sprintf("%v\n%v", classA, classB)
+		case bytes.Equal(kvA.Key[:1], keeper.NFTKey):
+			var nftA, nftB nft.NFT
+			cdc.MustUnmarshal(kvA.Value, &nftA)
+			cdc.MustUnmarshal(kvB.Value, &nftB)
+			return fmt.Sprintf("%v\n%v", nftA, nftB)
+		case bytes.Equal(kvA.Key[:1], keeper.NFTOfClassByOwnerKey):
+			return fmt.Sprintf("%v\n%v", kvA.Value, kvB.Value)
+		case bytes.Equal(kvA.Key[:1], keeper.OwnerKey):
+			var ownerA, ownerB sdk.AccAddress
+			ownerA = sdk.AccAddress(kvA.Value)
+			ownerB = sdk.AccAddress(kvB.Value)
+			return fmt.Sprintf("%v\n%v", ownerA, ownerB)
+		case bytes.Equal(kvA.Key[:1], keeper.ClassTotalSupply):
+			var supplyA, supplyB uint64
+			supplyA = sdk.BigEndianToUint64(kvA.Value)
+			supplyB = sdk.BigEndianToUint64(kvB.Value)
+			return fmt.Sprintf("%v\n%v", supplyA, supplyB)
+		default:
+			panic(fmt.Sprintf("invalid nft key %X", kvA.Key))
+		}
+	}
+}
--- a/x/nft/simulation/decoder_test.go
+++ b/x/nft/simulation/decoder_test.go
@ -0,0 +1,84 @@
+package simulation_test
+
+import (
+	"fmt"
+	"testing"
+
+	"github.com/stretchr/testify/require"
+
+	"github.com/cosmos/cosmos-sdk/crypto/keys/ed25519"
+	"github.com/cosmos/cosmos-sdk/simapp"
+	sdk "github.com/cosmos/cosmos-sdk/types"
+	"github.com/cosmos/cosmos-sdk/types/kv"
+	"github.com/cosmos/cosmos-sdk/x/nft"
+	"github.com/cosmos/cosmos-sdk/x/nft/keeper"
+	"github.com/cosmos/cosmos-sdk/x/nft/simulation"
+)
+
+var (
+	ownerPk1   = ed25519.GenPrivKey().PubKey()
+	ownerAddr1 = sdk.AccAddress(ownerPk1.Address())
+)
+
+func TestDecodeStore(t *testing.T) {
+	cdc := simapp.MakeTestEncodingConfig().Codec
+	dec := simulation.NewDecodeStore(cdc)
+
+	class := nft.Class{
+		Id:          "ClassID",
+		Name:        "ClassName",
+		Symbol:      "ClassSymbol",
+		Description: "ClassDescription",
+		Uri:         "ClassURI",
+	}
+	classBz, err := cdc.Marshal(&class)
+	require.NoError(t, err)
+
+	nft := nft.NFT{
+		ClassId: "ClassID",
+		Id:      "NFTID",
+		Uri:     "NFTURI",
+	}
+	nftBz, err := cdc.Marshal(&nft)
+	require.NoError(t, err)
+
+	nftOfClassByOwnerValue := []byte{0x01}
+
+	totalSupply := 1
+	totalSupplyBz := sdk.Uint64ToBigEndian(1)
+
+	kvPairs := kv.Pairs{
+		Pairs: []kv.Pair{
+			{Key: []byte(keeper.ClassKey), Value: classBz},
+			{Key: []byte(keeper.NFTKey), Value: nftBz},
+			{Key: []byte(keeper.NFTOfClassByOwnerKey), Value: nftOfClassByOwnerValue},
+			{Key: []byte(keeper.OwnerKey), Value: ownerAddr1},
+			{Key: []byte(keeper.ClassTotalSupply), Value: totalSupplyBz},
+			{Key: []byte{0x99}, Value: []byte{0x99}},
+		},
+	}
+
+	tests := []struct {
+		name        string
+		expectErr   bool
+		expectedLog string
+	}{
+		{"Class", false, fmt.Sprintf("%v\n%v", class, class)},
+		{"NFT", false, fmt.Sprintf("%v\n%v", nft, nft)},
+		{"NFTOfClassByOwnerKey", false, fmt.Sprintf("%v\n%v", nftOfClassByOwnerValue, nftOfClassByOwnerValue)},
+		{"OwnerKey", false, fmt.Sprintf("%v\n%v", ownerAddr1, ownerAddr1)},
+		{"ClassTotalSupply", false, fmt.Sprintf("%v\n%v", totalSupply, totalSupply)},
+		{"other", true, ""},
+	}
+
+	for i, tt := range tests {
+		i, tt := i, tt
+		t.Run(tt.name, func(t *testing.T) {
+			if tt.expectErr {
+				require.Panics(t, func() { dec(kvPairs.Pairs[i], kvPairs.Pairs[i]) }, tt.name)
+			} else {
+				require.Equal(t, tt.expectedLog, dec(kvPairs.Pairs[i], kvPairs.Pairs[i]), tt.name)
+			}
+		})
+	}
+}
--- a/x/nft/simulation/genesis.go
+++ b/x/nft/simulation/genesis.go
@ -0,0 +1,67 @@
+package simulation
+
+import (
+	"math/rand"
+
+	"github.com/cosmos/cosmos-sdk/types/module"
+	simtypes "github.com/cosmos/cosmos-sdk/types/simulation"
+	"github.com/cosmos/cosmos-sdk/x/nft"
+)
+
+// genClasses returns a slice of nft class.
+func genClasses(r *rand.Rand, accounts []simtypes.Account) []*nft.Class {
+	classes := make([]*nft.Class, len(accounts)-1)
+	for i := 0; i < len(accounts)-1; i++ {
+		classes[i] = &nft.Class{
+			Id:          simtypes.RandStringOfLength(r, 10),
+			Name:        simtypes.RandStringOfLength(r, 10),
+			Symbol:      simtypes.RandStringOfLength(r, 10),
+			Description: simtypes.RandStringOfLength(r, 10),
+			Uri:         simtypes.RandStringOfLength(r, 10),
+		}
+	}
+	return classes
+}
+
+// genNFT returns a slice of nft.
+func genNFT(r *rand.Rand, classID string, accounts []simtypes.Account) []*nft.Entry {
+	entries := make([]*nft.Entry, len(accounts)-1)
+	for i := 0; i < len(accounts)-1; i++ {
+		owner := accounts[i]
+		entries[i] = &nft.Entry{
+			Owner: owner.Address.String(),
+			Nfts: []*nft.NFT{
+				{
+					ClassId: classID,
+					Id:      simtypes.RandStringOfLength(r, 10),
+					Uri:     simtypes.RandStringOfLength(r, 10),
+				},
+			},
+		}
+	}
+	return entries
+}
+
+// RandomizedGenState generates a random GenesisState for nft.
+func RandomizedGenState(simState *module.SimulationState) {
+	var classes []*nft.Class
+	simState.AppParams.GetOrGenerate(
+		simState.Cdc, "nft", &classes, simState.Rand,
+		func(r *rand.Rand) { classes = genClasses(r, simState.Accounts) },
+	)
+
+	var entries []*nft.Entry
+	simState.AppParams.GetOrGenerate(
+		simState.Cdc, "nft", &entries, simState.Rand,
+		func(r *rand.Rand) {
+			class := classes[r.Int63n(int64(len(classes)))]
+			entries = genNFT(r, class.Id, simState.Accounts)
+		},
+	)
+
+	nftGenesis := &nft.GenesisState{
+		Classes: classes,
+		Entries: entries,
+	}
+	simState.GenState[nft.ModuleName] = simState.Cdc.MustMarshalJSON(nftGenesis)
+}
--- a/x/nft/simulation/genesis_test.go
+++ b/x/nft/simulation/genesis_test.go
@ -0,0 +1,39 @@
+package simulation_test
+
+import (
+	"encoding/json"
+	"math/rand"
+	"testing"
+
+	"github.com/stretchr/testify/require"
+
+	"github.com/cosmos/cosmos-sdk/simapp"
+	"github.com/cosmos/cosmos-sdk/types/module"
+	simtypes "github.com/cosmos/cosmos-sdk/types/simulation"
+	"github.com/cosmos/cosmos-sdk/x/nft"
+	"github.com/cosmos/cosmos-sdk/x/nft/simulation"
+)
+
+func TestRandomizedGenState(t *testing.T) {
+	app := simapp.Setup(t, false)
+
+	s := rand.NewSource(1)
+	r := rand.New(s)
+
+	simState := module.SimulationState{
+		AppParams:    make(simtypes.AppParams),
+		Cdc:          app.AppCodec(),
+		Rand:         r,
+		NumBonded:    3,
+		Accounts:     simtypes.RandomAccounts(r, 3),
+		InitialStake: 1000,
+		GenState:     make(map[string]json.RawMessage),
+	}
+
+	simulation.RandomizedGenState(&simState)
+	var nftGenesis nft.GenesisState
+	simState.Cdc.MustUnmarshalJSON(simState.GenState[nft.ModuleName], &nftGenesis)
+
+	require.Len(t, nftGenesis.Classes, len(simState.Accounts)-1)
+	require.Len(t, nftGenesis.Entries, len(simState.Accounts)-1)
+}
--- a/x/nft/simulation/operations.go
+++ b/x/nft/simulation/operations.go
@ -0,0 +1,164 @@
+package simulation
+
+import (
+	"math/rand"
+
+	"github.com/cosmos/cosmos-sdk/baseapp"
+	"github.com/cosmos/cosmos-sdk/codec"
+	cdctypes "github.com/cosmos/cosmos-sdk/codec/types"
+	"github.com/cosmos/cosmos-sdk/simapp/helpers"
+	simappparams "github.com/cosmos/cosmos-sdk/simapp/params"
+	sdk "github.com/cosmos/cosmos-sdk/types"
+	simtypes "github.com/cosmos/cosmos-sdk/types/simulation"
+	"github.com/cosmos/cosmos-sdk/x/nft"
+
+	"github.com/cosmos/cosmos-sdk/x/nft/keeper"
+
+	"github.com/cosmos/cosmos-sdk/x/simulation"
+)
+
+const (
+	// Simulation operation weights constants
+	OpWeightMsgSend = "op_weight_msg_send"
+)
+
+const (
+	// nft operations weights
+	WeightSend = 100
+)
+
+var (
+	TypeMsgSend = sdk.MsgTypeURL(&nft.MsgSend{})
+)
+
+// WeightedOperations returns all the operations from the module with their respective weights
+func WeightedOperations(
+	registry cdctypes.InterfaceRegistry,
+	appParams simtypes.AppParams,
+	cdc codec.JSONCodec,
+	ak nft.AccountKeeper,
+	bk nft.BankKeeper,
+	k keeper.Keeper) simulation.WeightedOperations {
+
+	var (
+		weightMsgSend int
+	)
+
+	appParams.GetOrGenerate(cdc, OpWeightMsgSend, &weightMsgSend, nil,
+		func(_ *rand.Rand) {
+			weightMsgSend = WeightSend
+		},
+	)
+
+	return simulation.WeightedOperations{
+		simulation.NewWeightedOperation(
+			weightMsgSend,
+			SimulateMsgSend(codec.NewProtoCodec(registry), ak, bk, k),
+		),
+	}
+}
+
+// SimulateMsgSend generates a MsgSend with random values.
+func SimulateMsgSend(
+	cdc *codec.ProtoCodec,
+	ak nft.AccountKeeper,
+	bk nft.BankKeeper,
+	k keeper.Keeper) simtypes.Operation {
+	return func(
+		r *rand.Rand, app *baseapp.BaseApp, ctx sdk.Context, accs []simtypes.Account, chainID string,
+	) (simtypes.OperationMsg, []simtypes.FutureOperation, error) {
+		sender, _ := simtypes.RandomAcc(r, accs)
+		receiver, _ := simtypes.RandomAcc(r, accs)
+
+		if sender.Address.Equals(receiver.Address) {
+			return simtypes.NoOpMsg(nft.ModuleName, TypeMsgSend, "sender and receiver are same"), nil, nil
+		}
+
+		senderAcc := ak.GetAccount(ctx, sender.Address)
+		spendableCoins := bk.SpendableCoins(ctx, sender.Address)
+		fees, err := simtypes.RandomFees(r, ctx, spendableCoins)
+		if err != nil {
+			return simtypes.NoOpMsg(nft.ModuleName, TypeMsgSend, err.Error()), nil, err
+		}
+
+		spendLimit := spendableCoins.Sub(fees)
+		if spendLimit == nil {
+			return simtypes.NoOpMsg(nft.ModuleName, TypeMsgSend, "spend limit is nil"), nil, nil
+		}
+
+		n, err := randNFT(ctx, r, k, senderAcc.GetAddress())
+		if err != nil {
+			return simtypes.NoOpMsg(nft.ModuleName, TypeMsgSend, err.Error()), nil, err
+		}
+
+		msg := &nft.MsgSend{
+			ClassId:  n.ClassId,
+			Id:       n.Id,
+			Sender:   senderAcc.GetAddress().String(),
+			Receiver: receiver.Address.String(),
+		}
+
+		txCfg := simappparams.MakeTestEncodingConfig().TxConfig
+		tx, err := helpers.GenTx(
+			txCfg,
+			[]sdk.Msg{msg},
+			fees,
+			helpers.DefaultGenTxGas,
+			chainID,
+			[]uint64{senderAcc.GetAccountNumber()},
+			[]uint64{senderAcc.GetSequence()},
+			sender.PrivKey,
+		)
+		if err != nil {
+			return simtypes.NoOpMsg(nft.ModuleName, TypeMsgSend, "unable to generate mock tx"), nil, err
+		}
+
+		_, _, err = app.SimDeliver(txCfg.TxEncoder(), tx)
+		if err != nil {
+			return simtypes.NoOpMsg(nft.ModuleName, sdk.MsgTypeURL(msg), "unable to deliver tx"), nil, err
+		}
+
+		return simtypes.NewOperationMsg(msg, true, "", cdc), nil, err
+	}
+}
+
+func randNFT(ctx sdk.Context, r *rand.Rand, k keeper.Keeper, minter sdk.AccAddress) (nft.NFT, error) {
+	c, err := randClass(ctx, r, k)
+	if err != nil {
+		return nft.NFT{}, err
+	}
+	ns := k.GetNFTsOfClassByOwner(ctx, c.Id, minter)
+	if len(ns) > 0 {
+		return ns[r.Intn(len(ns))], nil
+	}
+
+	n := nft.NFT{
+		ClassId: c.Id,
+		Id:      simtypes.RandStringOfLength(r, 10),
+		Uri:     simtypes.RandStringOfLength(r, 10),
+	}
+	err = k.Mint(ctx, n, minter)
+	if err != nil {
+		return nft.NFT{}, err
+	}
+	return n, nil
+}
+
+func randClass(ctx sdk.Context, r *rand.Rand, k keeper.Keeper) (nft.Class, error) {
+	classes := k.GetClasses(ctx)
+	if len(classes) == 0 {
+		c := nft.Class{
+			Id:          simtypes.RandStringOfLength(r, 10),
+			Name:        simtypes.RandStringOfLength(r, 10),
+			Symbol:      simtypes.RandStringOfLength(r, 10),
+			Description: simtypes.RandStringOfLength(r, 10),
+			Uri:         simtypes.RandStringOfLength(r, 10),
+		}
+		err := k.SaveClass(ctx, c)
+		if err != nil {
+			return nft.Class{}, err
+		}
+		return c, nil
+	}
+	return *classes[r.Intn(len(classes))], nil
+}
--- a/x/nft/simulation/operations_test.go
+++ b/x/nft/simulation/operations_test.go
@ -0,0 +1,115 @@
+package simulation_test
+
+import (
+	"math/rand"
+	"testing"
+	"time"
+
+	"github.com/stretchr/testify/suite"
+
+	abci "github.com/tendermint/tendermint/abci/types"
+	tmproto "github.com/tendermint/tendermint/proto/tendermint/types"
+
+	"github.com/cosmos/cosmos-sdk/codec"
+	"github.com/cosmos/cosmos-sdk/simapp"
+	sdk "github.com/cosmos/cosmos-sdk/types"
+	simtypes "github.com/cosmos/cosmos-sdk/types/simulation"
+	"github.com/cosmos/cosmos-sdk/x/bank/testutil"
+	"github.com/cosmos/cosmos-sdk/x/nft"
+	"github.com/cosmos/cosmos-sdk/x/nft/simulation"
+)
+
+type SimTestSuite struct {
+	suite.Suite
+
+	ctx sdk.Context
+	app *simapp.SimApp
+}
+
+func (suite *SimTestSuite) SetupTest() {
+	checkTx := false
+	app := simapp.Setup(suite.T(), checkTx)
+	suite.app = app
+	suite.ctx = app.BaseApp.NewContext(checkTx, tmproto.Header{})
+}
+
+func (suite *SimTestSuite) TestWeightedOperations() {
+	weightedOps := simulation.WeightedOperations(
+		suite.app.InterfaceRegistry(),
+		make(simtypes.AppParams),
+		suite.app.AppCodec(),
+		suite.app.AccountKeeper,
+		suite.app.BankKeeper, suite.app.NFTKeeper,
+	)
+
+	// setup 3 accounts
+	s := rand.NewSource(1)
+	r := rand.New(s)
+	accs := suite.getTestingAccounts(r, 3)
+
+	expected := []struct {
+		weight     int
+		opMsgRoute string
+		opMsgName  string
+	}{
+		{simulation.WeightSend, simulation.TypeMsgSend, simulation.TypeMsgSend},
+	}
+
+	for i, w := range weightedOps {
+		operationMsg, _, _ := w.Op()(r, suite.app.BaseApp, suite.ctx, accs, "")
+		// the following checks are very much dependent from the ordering of the output given
+		// by WeightedOperations. if the ordering in WeightedOperations changes some tests
+		// will fail
+		suite.Require().Equal(expected[i].weight, w.Weight(), "weight should be the same")
+		suite.Require().Equal(expected[i].opMsgRoute, operationMsg.Route, "route should be the same")
+		suite.Require().Equal(expected[i].opMsgName, operationMsg.Name, "operation Msg name should be the same")
+	}
+}
+
+func (suite *SimTestSuite) getTestingAccounts(r *rand.Rand, n int) []simtypes.Account {
+	accounts := simtypes.RandomAccounts(r, n)
+
+	initAmt := suite.app.StakingKeeper.TokensFromConsensusPower(suite.ctx, 200000)
+	initCoins := sdk.NewCoins(sdk.NewCoin("stake", initAmt))
+
+	// add coins to the accounts
+	for _, account := range accounts {
+		acc := suite.app.AccountKeeper.NewAccountWithAddress(suite.ctx, account.Address)
+		suite.app.AccountKeeper.SetAccount(suite.ctx, acc)
+		suite.Require().NoError(testutil.FundAccount(suite.app.BankKeeper, suite.ctx, account.Address, initCoins))
+	}
+
+	return accounts
+}
+
+func (suite *SimTestSuite) TestSimulateMsgSend() {
+	s := rand.NewSource(1)
+	r := rand.New(s)
+	accounts := suite.getTestingAccounts(r, 2)
+	blockTime := time.Now().UTC()
+	ctx := suite.ctx.WithBlockTime(blockTime)
+
+	// begin a new block
+	suite.app.BeginBlock(abci.RequestBeginBlock{
+		Header: tmproto.Header{
+			Height:  suite.app.LastBlockHeight() + 1,
+			AppHash: suite.app.LastCommitID().Hash,
+		},
+	})
+
+	// execute operation
+	registry := suite.app.InterfaceRegistry()
+	op := simulation.SimulateMsgSend(codec.NewProtoCodec(registry), suite.app.AccountKeeper, suite.app.BankKeeper, suite.app.NFTKeeper)
+	operationMsg, futureOperations, err := op(r, suite.app.BaseApp, ctx, accounts, "")
+	suite.Require().NoError(err)
+
+	var msg nft.MsgSend
+	suite.app.AppCodec().UnmarshalJSON(operationMsg.Msg, &msg)
+	suite.Require().True(operationMsg.OK)
+	suite.Require().Len(futureOperations, 0)
+
+}
+
+func TestSimTestSuite(t *testing.T) {
+	suite.Run(t, new(SimTestSuite))
+}