fix: simulations don't generate EVM transactions (#996)

* use SimAppChainId instead of the default cosmos-sdk simulation chainid

* implement custom RandomGenesisAccounts for auth module simulation

* use customized RandomGenesisAccounts

* generate random ethereum txs operations

* use sdk.DefaultBondDenom

* implement WeightedOperations

* fix self assignment

* use customized RandomAccounts to generate accounts with ethsecp256k1 private key

* RandomAccounts generate random accounts with ethsecp256k1 private key

* implement SimulateEthSimpleTransfer

* implement SimulateEthCreateContract

* refactor and implement operationSimulateEthCallContract as future operations of SimulateEthCreateContract

* Update app/app.go

Co-authored-by: Federico Kunze Küllmer <31522760+fedekunze@users.noreply.github.com>

* Update app/test_helpers.go

Co-authored-by: Federico Kunze Küllmer <31522760+fedekunze@users.noreply.github.com>

* Update x/evm/simulation/operations.go

Co-authored-by: Federico Kunze Küllmer <31522760+fedekunze@users.noreply.github.com>

* Update x/evm/simulation/operations.go

Co-authored-by: Federico Kunze Küllmer <31522760+fedekunze@users.noreply.github.com>

* Update app/test_helpers.go

Co-authored-by: Federico Kunze Küllmer <31522760+fedekunze@users.noreply.github.com>

* fix r.Read return only 1 result

* fix linter errors

* change SimulateContext to private

* return transferable amount immediately

* fix linter errors

* fix linter errors: append assign to different slice

* fix linter error: remove else block

* use gofumpt

* Update x/evm/simulation/operations.go

Co-authored-by: Federico Kunze Küllmer <31522760+fedekunze@users.noreply.github.com>

* Update x/evm/simulation/operations.go

Co-authored-by: Federico Kunze Küllmer <31522760+fedekunze@users.noreply.github.com>

* Update x/evm/simulation/operations.go

Co-authored-by: Federico Kunze Küllmer <31522760+fedekunze@users.noreply.github.com>

* Update x/evm/simulation/operations.go

Co-authored-by: Federico Kunze Küllmer <31522760+fedekunze@users.noreply.github.com>

* fix recipient typo

* add nosec comment to escape Potential hardcoded credentials check

* add comments

* use SimAppChainID as valid chainID

* do not specify genesis.json to create random genesis state for simulation

* sub estimateGas to avoid overflow

* correct RandomGenesisAccounts comments

Co-authored-by: Federico Kunze Küllmer <31522760+fedekunze@users.noreply.github.com>

* correct app/test_helpers.go comments

Co-authored-by: Federico Kunze Küllmer <31522760+fedekunze@users.noreply.github.com>

* remove NewTxConfig

* implement RegisterStoreDecoder

* remove WeightMsgEthCallContract and adjust weights

* use gofmt

* update godoc

* use types.DefaultEVMDenom in evm genesis params

Co-authored-by: Federico Kunze Küllmer <31522760+fedekunze@users.noreply.github.com>

* use types.DefaultEVMDenom

Co-authored-by: Federico Kunze Küllmer <31522760+fedekunze@users.noreply.github.com>

* update godoc

* Update x/evm/simulation/genesis.go

* replace evmdenom with bonddenom in AppStateFn

* fix AppStateFn

* fix lint error

* add ParamChanges for RandomizedParams

* rename app/test_helpers.go -> app/utils.go

* testing for RandomGenesisAccounts

* use cdc for marshaling

* lint

* changelog

* changelog 2

Co-authored-by: Federico Kunze Küllmer <31522760+fedekunze@users.noreply.github.com>
Co-authored-by: crypto-facs <84574577+crypto-facs@users.noreply.github.com>
Co-authored-by: Freddy Caceres <freddy.caceres@crypto.com>
Co-authored-by: Federico Kunze Küllmer <federico.kunze94@gmail.com>

CHANGELOG.md

@@ -45,12 +45,12 @@ Ref: https://keepachangelog.com/en/1.0.0/
 ### Bug Fixes
 
 * (rpc) [tharsis#1050](https://github.com/tharsis/ethermint/pull/1050) `eth_getBlockByNumber` fix on batch transactions
+* (app) [tharsis#658](https://github.com/tharsis/ethermint/issues/658) Support simulations for the EVM.
 
 ### API Breaking
 
 * (evm) [tharsis#1051](https://github.com/tharsis/ethermint/pull/1051) Context block height fix on TraceTx. Removes `tx_index` on `QueryTraceTxRequest` proto type.
 
-
 ## [v0.13.0] - 2022-04-05
 
 ### API Breaking

Makefile

@@ -342,10 +342,9 @@ test-sim-nondeterminism:
 	@go test -mod=readonly $(SIMAPP) -run TestAppStateDeterminism -Enabled=true \
 		-NumBlocks=100 -BlockSize=200 -Commit=true -Period=0 -v -timeout 24h
 
-test-sim-custom-genesis-fast:
+test-sim-random-genesis-fast:
 	@echo "Running custom genesis simulation..."
-	@echo "By default, ${HOME}/.$(ETHERMINT_DIR)/config/genesis.json will be used."
-	@go test -mod=readonly $(SIMAPP) -run TestFullAppSimulation -Genesis=${HOME}/.$(ETHERMINT_DIR)/config/genesis.json \
+	@go test -mod=readonly $(SIMAPP) -run TestFullAppSimulation \
 		-Enabled=true -NumBlocks=100 -BlockSize=200 -Commit=true -Seed=99 -Period=5 -v -timeout 24h
 
 test-sim-import-export: runsim
@@ -356,10 +355,9 @@ test-sim-after-import: runsim
 	@echo "Running application simulation-after-import. This may take several minutes..."
 	@$(BINDIR)/runsim -Jobs=4 -SimAppPkg=$(SIMAPP) -ExitOnFail 50 5 TestAppSimulationAfterImport
 
-test-sim-custom-genesis-multi-seed: runsim
+test-sim-random-genesis-multi-seed: runsim
 	@echo "Running multi-seed custom genesis simulation..."
-	@echo "By default, ${HOME}/.$(ETHERMINT_DIR)/config/genesis.json will be used."
-	@$(BINDIR)/runsim -Genesis=${HOME}/.$(ETHERMINT_DIR)/config/genesis.json -SimAppPkg=$(SIMAPP) -ExitOnFail 400 5 TestFullAppSimulation
+	@$(BINDIR)/runsim -SimAppPkg=$(SIMAPP) -ExitOnFail 400 5 TestFullAppSimulation
 
 test-sim-multi-seed-long: runsim
 	@echo "Running long multi-seed application simulation. This may take awhile!"

app/app.go

@@ -536,7 +536,8 @@ func NewEthermintApp(
 	// NOTE: this is not required apps that don't use the simulator for fuzz testing
 	// transactions
 	app.sm = module.NewSimulationManager(
-		auth.NewAppModule(appCodec, app.AccountKeeper, authsims.RandomGenesisAccounts),
+		// Use custom RandomGenesisAccounts so that auth module could create random EthAccounts in genesis state when genesis.json not specified
+		auth.NewAppModule(appCodec, app.AccountKeeper, RandomGenesisAccounts),
 		bank.NewAppModule(appCodec, app.BankKeeper, app.AccountKeeper),
 		capability.NewAppModule(appCodec, *app.CapabilityKeeper),
 		gov.NewAppModule(appCodec, app.GovKeeper, app.AccountKeeper, app.BankKeeper),

app/simulation_test.go

@@ -15,7 +15,6 @@ import (
 	"github.com/cosmos/cosmos-sdk/simapp/params"
 	"github.com/cosmos/cosmos-sdk/store"
 	sdk "github.com/cosmos/cosmos-sdk/types"
-	simtypes "github.com/cosmos/cosmos-sdk/types/simulation"
 	authtypes "github.com/cosmos/cosmos-sdk/x/auth/types"
 	banktypes "github.com/cosmos/cosmos-sdk/x/bank/types"
 	capabilitytypes "github.com/cosmos/cosmos-sdk/x/capability/types"
@@ -72,6 +71,8 @@ func TestFullAppSimulation(t *testing.T) {
 	}
 	require.NoError(t, err, "simulation setup failed")
 
+	config.ChainID = SimAppChainID
+
 	defer func() {
 		db.Close()
 		require.NoError(t, os.RemoveAll(dir))
@@ -85,8 +86,8 @@ func TestFullAppSimulation(t *testing.T) {
 		t,
 		os.Stdout,
 		app.BaseApp,
-		simapp.AppStateFn(app.AppCodec(), app.SimulationManager()),
-		simtypes.RandomAccounts, // Replace with own random account function if using keys other than secp256k1
+		StateFn(app.AppCodec(), app.SimulationManager()),
+		RandomAccounts, // Replace with own random account function if using keys other than secp256k1
 		simapp.SimulationOperations(app, app.AppCodec(), config),
 		app.ModuleAccountAddrs(),
 		config,
@@ -110,6 +111,8 @@ func TestAppImportExport(t *testing.T) {
 	}
 	require.NoError(t, err, "simulation setup failed")
 
+	config.ChainID = SimAppChainID
+
 	defer func() {
 		db.Close()
 		require.NoError(t, os.RemoveAll(dir))
@@ -123,8 +126,8 @@ func TestAppImportExport(t *testing.T) {
 		t,
 		os.Stdout,
 		app.BaseApp,
-		simapp.AppStateFn(app.AppCodec(), app.SimulationManager()),
-		simtypes.RandomAccounts, // Replace with own random account function if using keys other than secp256k1
+		StateFn(app.AppCodec(), app.SimulationManager()),
+		RandomAccounts, // Replace with own random account function if using keys other than secp256k1
 		simapp.SimulationOperations(app, app.AppCodec(), config),
 		app.ModuleAccountAddrs(),
 		config,
@@ -163,8 +166,8 @@ func TestAppImportExport(t *testing.T) {
 	err = json.Unmarshal(exported.AppState, &genesisState)
 	require.NoError(t, err)
 
-	ctxA := app.NewContext(true, tmproto.Header{Height: app.LastBlockHeight()})
-	ctxB := newApp.NewContext(true, tmproto.Header{Height: app.LastBlockHeight()})
+	ctxA := app.NewContext(true, tmproto.Header{Height: app.LastBlockHeight(), ChainID: SimAppChainID})
+	ctxB := newApp.NewContext(true, tmproto.Header{Height: app.LastBlockHeight(), ChainID: SimAppChainID})
 	newApp.mm.InitGenesis(ctxB, app.AppCodec(), genesisState)
 	newApp.StoreConsensusParams(ctxB, exported.ConsensusParams)
 
@@ -210,6 +213,8 @@ func TestAppSimulationAfterImport(t *testing.T) {
 	}
 	require.NoError(t, err, "simulation setup failed")
 
+	config.ChainID = SimAppChainID
+
 	defer func() {
 		db.Close()
 		require.NoError(t, os.RemoveAll(dir))
@@ -223,8 +228,8 @@ func TestAppSimulationAfterImport(t *testing.T) {
 		t,
 		os.Stdout,
 		app.BaseApp,
-		simapp.AppStateFn(app.AppCodec(), app.SimulationManager()),
-		simtypes.RandomAccounts, // Replace with own random account function if using keys other than secp256k1
+		StateFn(app.AppCodec(), app.SimulationManager()),
+		RandomAccounts, // Replace with own random account function if using keys other than secp256k1
 		simapp.SimulationOperations(app, app.AppCodec(), config),
 		app.ModuleAccountAddrs(),
 		config,
@@ -264,6 +269,7 @@ func TestAppSimulationAfterImport(t *testing.T) {
 	require.Equal(t, appName, newApp.Name())
 
 	newApp.InitChain(abci.RequestInitChain{
+		ChainId:       SimAppChainID,
 		AppStateBytes: exported.AppState,
 	})
 
@@ -271,8 +277,8 @@ func TestAppSimulationAfterImport(t *testing.T) {
 		t,
 		os.Stdout,
 		newApp.BaseApp,
-		simapp.AppStateFn(app.AppCodec(), app.SimulationManager()),
-		simtypes.RandomAccounts, // Replace with own random account function if using keys other than secp256k1
+		StateFn(app.AppCodec(), app.SimulationManager()),
+		RandomAccounts, // Replace with own random account function if using keys other than secp256k1
 		simapp.SimulationOperations(newApp, newApp.AppCodec(), config),
 		app.ModuleAccountAddrs(),
 		config,
@@ -322,8 +328,8 @@ func TestAppStateDeterminism(t *testing.T) {
 				t,
 				os.Stdout,
 				app.BaseApp,
-				simapp.AppStateFn(app.AppCodec(), app.SimulationManager()),
-				simtypes.RandomAccounts, // Replace with own random account function if using keys other than secp256k1
+				StateFn(app.AppCodec(), app.SimulationManager()),
+				RandomAccounts, // Replace with own random account function if using keys other than secp256k1
 				simapp.SimulationOperations(app, app.AppCodec(), config),
 				app.ModuleAccountAddrs(),
 				config,

app/test_helpers.go

@@ -1,64 +0,0 @@
-package app
-
-import (
-	"encoding/json"
-	"time"
-
-	"github.com/cosmos/cosmos-sdk/simapp"
-	"github.com/tharsis/ethermint/encoding"
-
-	abci "github.com/tendermint/tendermint/abci/types"
-	"github.com/tendermint/tendermint/libs/log"
-	tmproto "github.com/tendermint/tendermint/proto/tendermint/types"
-	tmtypes "github.com/tendermint/tendermint/types"
-	dbm "github.com/tendermint/tm-db"
-)
-
-// DefaultConsensusParams defines the default Tendermint consensus params used in
-// EthermintApp testing.
-var DefaultConsensusParams = &abci.ConsensusParams{
-	Block: &abci.BlockParams{
-		MaxBytes: 200000,
-		MaxGas:   -1, // no limit
-	},
-	Evidence: &tmproto.EvidenceParams{
-		MaxAgeNumBlocks: 302400,
-		MaxAgeDuration:  504 * time.Hour, // 3 weeks is the max duration
-		MaxBytes:        10000,
-	},
-	Validator: &tmproto.ValidatorParams{
-		PubKeyTypes: []string{
-			tmtypes.ABCIPubKeyTypeEd25519,
-		},
-	},
-}
-
-// Setup initializes a new EthermintApp. A Nop logger is set in EthermintApp.
-func Setup(isCheckTx bool, patchGenesis func(*EthermintApp, simapp.GenesisState) simapp.GenesisState) *EthermintApp {
-	db := dbm.NewMemDB()
-	app := NewEthermintApp(log.NewNopLogger(), db, nil, true, map[int64]bool{}, DefaultNodeHome, 5, encoding.MakeConfig(ModuleBasics), simapp.EmptyAppOptions{})
-	if !isCheckTx {
-		// init chain must be called to stop deliverState from being nil
-		genesisState := NewDefaultGenesisState()
-		if patchGenesis != nil {
-			genesisState = patchGenesis(app, genesisState)
-		}
-
-		stateBytes, err := json.MarshalIndent(genesisState, "", " ")
-		if err != nil {
-			panic(err)
-		}
-
-		// Initialize the chain
-		app.InitChain(
-			abci.RequestInitChain{
-				ChainId:         "ethermint_9000-1",
-				Validators:      []abci.ValidatorUpdate{},
-				ConsensusParams: DefaultConsensusParams,
-				AppStateBytes:   stateBytes,
-			},
-		)
-	}
-
-	return app
-}

app/utils.go

@@ -0,0 +1,169 @@
+package app
+
+import (
+	"encoding/json"
+	"math/rand"
+	"time"
+
+	"github.com/cosmos/cosmos-sdk/codec"
+	"github.com/cosmos/cosmos-sdk/crypto/keys/secp256k1"
+	"github.com/cosmos/cosmos-sdk/simapp"
+	"github.com/cosmos/cosmos-sdk/types/module"
+	authtypes "github.com/cosmos/cosmos-sdk/x/auth/types"
+	stakingtypes "github.com/cosmos/cosmos-sdk/x/staking/types"
+
+	"github.com/tharsis/ethermint/encoding"
+	ethermint "github.com/tharsis/ethermint/types"
+	evmtypes "github.com/tharsis/ethermint/x/evm/types"
+
+	"github.com/cosmos/cosmos-sdk/crypto/keys/ed25519"
+	sdk "github.com/cosmos/cosmos-sdk/types"
+	simtypes "github.com/cosmos/cosmos-sdk/types/simulation"
+	"github.com/ethereum/go-ethereum/common"
+	"github.com/ethereum/go-ethereum/crypto"
+	abci "github.com/tendermint/tendermint/abci/types"
+	"github.com/tendermint/tendermint/libs/log"
+	tmproto "github.com/tendermint/tendermint/proto/tendermint/types"
+	tmtypes "github.com/tendermint/tendermint/types"
+	dbm "github.com/tendermint/tm-db"
+	"github.com/tharsis/ethermint/crypto/ethsecp256k1"
+)
+
+// DefaultConsensusParams defines the default Tendermint consensus params used in
+// EthermintApp testing.
+var DefaultConsensusParams = &abci.ConsensusParams{
+	Block: &abci.BlockParams{
+		MaxBytes: 200000,
+		MaxGas:   -1, // no limit
+	},
+	Evidence: &tmproto.EvidenceParams{
+		MaxAgeNumBlocks: 302400,
+		MaxAgeDuration:  504 * time.Hour, // 3 weeks is the max duration
+		MaxBytes:        10000,
+	},
+	Validator: &tmproto.ValidatorParams{
+		PubKeyTypes: []string{
+			tmtypes.ABCIPubKeyTypeEd25519,
+		},
+	},
+}
+
+// Setup initializes a new EthermintApp. A Nop logger is set in EthermintApp.
+func Setup(isCheckTx bool, patchGenesis func(*EthermintApp, simapp.GenesisState) simapp.GenesisState) *EthermintApp {
+	db := dbm.NewMemDB()
+	app := NewEthermintApp(log.NewNopLogger(), db, nil, true, map[int64]bool{}, DefaultNodeHome, 5, encoding.MakeConfig(ModuleBasics), simapp.EmptyAppOptions{})
+	if !isCheckTx {
+		// init chain must be called to stop deliverState from being nil
+		genesisState := NewDefaultGenesisState()
+		if patchGenesis != nil {
+			genesisState = patchGenesis(app, genesisState)
+		}
+
+		stateBytes, err := json.MarshalIndent(genesisState, "", " ")
+		if err != nil {
+			panic(err)
+		}
+
+		// Initialize the chain
+		app.InitChain(
+			abci.RequestInitChain{
+				ChainId:         "ethermint_9000-1",
+				Validators:      []abci.ValidatorUpdate{},
+				ConsensusParams: DefaultConsensusParams,
+				AppStateBytes:   stateBytes,
+			},
+		)
+	}
+
+	return app
+}
+
+// RandomGenesisAccounts is used by the auth module to create random genesis accounts in simulation when a genesis.json is not specified.
+// In contrast, the default auth module's RandomGenesisAccounts implementation creates only base accounts and vestings accounts.
+func RandomGenesisAccounts(simState *module.SimulationState) authtypes.GenesisAccounts {
+	emptyCodeHash := crypto.Keccak256(nil)
+	genesisAccs := make(authtypes.GenesisAccounts, len(simState.Accounts))
+	for i, acc := range simState.Accounts {
+		bacc := authtypes.NewBaseAccountWithAddress(acc.Address)
+
+		ethacc := &ethermint.EthAccount{
+			BaseAccount: bacc,
+			CodeHash:    common.BytesToHash(emptyCodeHash).String(),
+		}
+		genesisAccs[i] = ethacc
+	}
+
+	return genesisAccs
+}
+
+// RandomAccounts creates random accounts with an ethsecp256k1 private key
+// TODO: replace secp256k1.GenPrivKeyFromSecret() with similar function in go-ethereum
+func RandomAccounts(r *rand.Rand, n int) []simtypes.Account {
+	accs := make([]simtypes.Account, n)
+
+	for i := 0; i < n; i++ {
+		// don't need that much entropy for simulation
+		privkeySeed := make([]byte, 15)
+		_, _ = r.Read(privkeySeed)
+
+		prv := secp256k1.GenPrivKeyFromSecret(privkeySeed)
+		ethPrv := &ethsecp256k1.PrivKey{}
+		_ = ethPrv.UnmarshalAmino(prv.Bytes())
+		accs[i].PrivKey = ethPrv
+		accs[i].PubKey = accs[i].PrivKey.PubKey()
+		accs[i].Address = sdk.AccAddress(accs[i].PubKey.Address())
+
+		accs[i].ConsKey = ed25519.GenPrivKeyFromSecret(privkeySeed)
+	}
+
+	return accs
+}
+
+// StateFn returns the initial application state using a genesis or the simulation parameters.
+// It is a wrapper of simapp.AppStateFn to replace evm param EvmDenom with staking param BondDenom.
+func StateFn(cdc codec.JSONCodec, simManager *module.SimulationManager) simtypes.AppStateFn {
+	return func(r *rand.Rand, accs []simtypes.Account, config simtypes.Config,
+	) (appState json.RawMessage, simAccs []simtypes.Account, chainID string, genesisTimestamp time.Time) {
+		appStateFn := simapp.AppStateFn(cdc, simManager)
+		appState, simAccs, chainID, genesisTimestamp = appStateFn(r, accs, config)
+
+		rawState := make(map[string]json.RawMessage)
+		err := json.Unmarshal(appState, &rawState)
+		if err != nil {
+			panic(err)
+		}
+
+		stakingStateBz, ok := rawState[stakingtypes.ModuleName]
+		if !ok {
+			panic("staking genesis state is missing")
+		}
+
+		stakingState := new(stakingtypes.GenesisState)
+		cdc.MustUnmarshalJSON(stakingStateBz, stakingState)
+
+		// we should get the BondDenom and make it the evmdenom.
+		// thus simulation accounts could have positive amount of gas token.
+		bondDenom := stakingState.Params.BondDenom
+
+		evmStateBz, ok := rawState[evmtypes.ModuleName]
+		if !ok {
+			panic("staking genesis state is missing")
+		}
+
+		evmState := new(evmtypes.GenesisState)
+		cdc.MustUnmarshalJSON(evmStateBz, evmState)
+
+		// we should replace the EvmDenom with BondDenom
+		evmState.Params.EvmDenom = bondDenom
+
+		// change appState back
+		rawState[evmtypes.ModuleName] = cdc.MustMarshalJSON(evmState)
+
+		// replace appstate
+		appState, err = json.Marshal(rawState)
+		if err != nil {
+			panic(err)
+		}
+		return appState, simAccs, chainID, genesisTimestamp
+	}
+}

app/utils_test.go

@@ -0,0 +1,55 @@
+package app
+
+import (
+	"math/rand"
+	"testing"
+
+	"github.com/stretchr/testify/require"
+
+	"github.com/cosmos/cosmos-sdk/types/module"
+	"github.com/cosmos/cosmos-sdk/x/auth"
+	authkeeper "github.com/cosmos/cosmos-sdk/x/auth/keeper"
+	authtypes "github.com/cosmos/cosmos-sdk/x/auth/types"
+	paramstypes "github.com/cosmos/cosmos-sdk/x/params/types"
+
+	ethermint "github.com/tharsis/ethermint/types"
+
+	"github.com/cosmos/cosmos-sdk/simapp"
+	sdk "github.com/cosmos/cosmos-sdk/types"
+)
+
+var maxTestingAccounts = 100
+var seed = int64(233)
+
+func TestRandomGenesisAccounts(t *testing.T) {
+	r := rand.New(rand.NewSource(seed))
+	accs := RandomAccounts(r, rand.Intn(maxTestingAccounts))
+
+	encodingConfig := MakeEncodingConfig()
+	appCodec := encodingConfig.Marshaler
+	cdc := encodingConfig.Amino
+
+	paramsKeeper := initParamsKeeper(appCodec, cdc, sdk.NewKVStoreKey(paramstypes.StoreKey), sdk.NewTransientStoreKey(paramstypes.StoreKey))
+	subSpace, find := paramsKeeper.GetSubspace(authtypes.ModuleName)
+	require.True(t, find)
+	accountKeeper := authkeeper.NewAccountKeeper(
+		appCodec, sdk.NewKVStoreKey(authtypes.StoreKey), subSpace, ethermint.ProtoAccount, maccPerms,
+	)
+	authModule := auth.NewAppModule(appCodec, accountKeeper, RandomGenesisAccounts)
+
+	genesisState := simapp.NewDefaultGenesisState(appCodec)
+	simState := &module.SimulationState{Accounts: accs, Cdc: appCodec, Rand: r, GenState: genesisState}
+	authModule.GenerateGenesisState(simState)
+
+	authStateBz, find := genesisState[authtypes.ModuleName]
+	require.True(t, find)
+
+	authState := new(authtypes.GenesisState)
+	appCodec.MustUnmarshalJSON(authStateBz, authState)
+	accounts, err := authtypes.UnpackAccounts(authState.Accounts)
+	require.NoError(t, err)
+	for _, acc := range accounts {
+		_, ok := acc.(ethermint.EthAccountI)
+		require.True(t, ok)
+	}
+}

x/evm/module.go

@@ -170,11 +170,13 @@ func (am AppModule) ExportGenesis(ctx sdk.Context, cdc codec.JSONCodec) json.Raw
 
 // RandomizedParams creates randomized evm param changes for the simulator.
 func (AppModule) RandomizedParams(r *rand.Rand) []simtypes.ParamChange {
-	return nil
+	return simulation.ParamChanges(r)
 }
 
 // RegisterStoreDecoder registers a decoder for evm module's types
-func (am AppModule) RegisterStoreDecoder(sdr sdk.StoreDecoderRegistry) {}
+func (am AppModule) RegisterStoreDecoder(sdr sdk.StoreDecoderRegistry) {
+	sdr[types.StoreKey] = simulation.NewDecodeStore()
+}
 
 // ProposalContents doesn't return any content functions for governance proposals.
 func (AppModule) ProposalContents(simState module.SimulationState) []simtypes.WeightedProposalContent {
@@ -188,5 +190,7 @@ func (AppModule) GenerateGenesisState(simState *module.SimulationState) {
 
 // WeightedOperations returns the all the evm module operations with their respective weights.
 func (am AppModule) WeightedOperations(simState module.SimulationState) []simtypes.WeightedOperation {
-	return nil
+	return simulation.WeightedOperations(
+		simState.AppParams, simState.Cdc, am.ak, am.keeper,
+	)
 }

x/evm/simulation/decoder.go

@@ -0,0 +1,31 @@
+package simulation
+
+import (
+	"bytes"
+	"fmt"
+
+	"github.com/cosmos/cosmos-sdk/types/kv"
+	"github.com/ethereum/go-ethereum/common"
+	"github.com/tharsis/ethermint/x/evm/types"
+)
+
+// NewDecodeStore returns a decoder function closure that unmarshals the KVPair's
+// Value to the corresponding evm type.
+func NewDecodeStore() func(kvA, kvB kv.Pair) string {
+	return func(kvA, kvB kv.Pair) string {
+		switch {
+		case bytes.Equal(kvA.Key[:1], types.KeyPrefixStorage):
+			storageHashA := common.BytesToHash(kvA.Value).Hex()
+			storageHashB := common.BytesToHash(kvB.Value).Hex()
+
+			return fmt.Sprintf("%v\n%v", storageHashA, storageHashB)
+		case bytes.Equal(kvA.Key[:1], types.KeyPrefixCode):
+			codeHashA := common.BytesToHash(kvA.Value).Hex()
+			codeHashB := common.BytesToHash(kvB.Value).Hex()
+
+			return fmt.Sprintf("%v\n%v", codeHashA, codeHashB)
+		default:
+			panic(fmt.Sprintf("invalid evm key prefix %X", kvA.Key[:1]))
+		}
+	}
+}

x/evm/simulation/genesis.go

@@ -3,18 +3,26 @@ package simulation
 import (
 	"encoding/json"
 	"fmt"
+	"math/rand"
 
 	"github.com/cosmos/cosmos-sdk/types/module"
 
 	"github.com/tharsis/ethermint/x/evm/types"
 )
 
+// GenExtraEIPs randomly generates specific extra eips or not.
+func genExtraEIPs(r *rand.Rand) []int64 {
+	var extraEIPs []int64
+	if r.Uint32()%2 == 0 {
+		extraEIPs = []int64{1344, 1884, 2200, 2929, 3198, 3529}
+	}
+	return extraEIPs
+}
+
 // RandomizedGenState generates a random GenesisState for nft
 func RandomizedGenState(simState *module.SimulationState) {
-	params := types.NewParams(types.DefaultEVMDenom, true, true, types.DefaultChainConfig())
-	if simState.Rand.Uint32()%2 == 0 {
-		params = types.NewParams(types.DefaultEVMDenom, true, true, types.DefaultChainConfig(), 1344, 1884, 2200, 2929, 3198, 3529)
-	}
+	extraEIPs := genExtraEIPs(simState.Rand)
+	params := types.NewParams(types.DefaultEVMDenom, true, true, types.DefaultChainConfig(), extraEIPs...)
 	evmGenesis := types.NewGenesisState(params, []types.GenesisAccount{})
 
 	bz, err := json.MarshalIndent(evmGenesis, "", " ")

x/evm/simulation/operations.go

@@ -0,0 +1,299 @@
+package simulation
+
+import (
+	"encoding/json"
+	"fmt"
+	"math/big"
+	"math/rand"
+	"time"
+
+	"github.com/cosmos/cosmos-sdk/baseapp"
+	"github.com/cosmos/cosmos-sdk/codec"
+	codectypes "github.com/cosmos/cosmos-sdk/codec/types"
+	sdk "github.com/cosmos/cosmos-sdk/types"
+	"github.com/cosmos/cosmos-sdk/types/module"
+	simtypes "github.com/cosmos/cosmos-sdk/types/simulation"
+	sdktx "github.com/cosmos/cosmos-sdk/types/tx"
+	"github.com/cosmos/cosmos-sdk/x/auth/tx"
+	"github.com/cosmos/cosmos-sdk/x/simulation"
+	"github.com/ethereum/go-ethereum/common"
+	"github.com/ethereum/go-ethereum/common/hexutil"
+	ethtypes "github.com/ethereum/go-ethereum/core/types"
+
+	"github.com/cosmos/cosmos-sdk/client"
+	cryptotypes "github.com/cosmos/cosmos-sdk/crypto/types"
+	"github.com/cosmos/cosmos-sdk/x/auth/signing"
+	"github.com/ethereum/go-ethereum/crypto"
+	"github.com/tharsis/ethermint/encoding"
+	"github.com/tharsis/ethermint/server/config"
+	"github.com/tharsis/ethermint/tests"
+	"github.com/tharsis/ethermint/x/evm/keeper"
+	"github.com/tharsis/ethermint/x/evm/types"
+)
+
+const (
+	/* #nosec */
+	OpWeightMsgEthSimpleTransfer = "op_weight_msg_eth_simple_transfer"
+	/* #nosec */
+	OpWeightMsgEthCreateContract = "op_weight_msg_eth_create_contract"
+	/* #nosec */
+	OpWeightMsgEthCallContract = "op_weight_msg_eth_call_contract"
+)
+
+const (
+	WeightMsgEthSimpleTransfer = 50
+	WeightMsgEthCreateContract = 50
+)
+
+var ErrNoEnoughBalance = fmt.Errorf("no enough balance")
+
+var maxWaitSeconds = 10
+
+type simulateContext struct {
+	context sdk.Context
+	bapp    *baseapp.BaseApp
+	rand    *rand.Rand
+	keeper  *keeper.Keeper
+}
+
+// WeightedOperations generate Two kinds of operations: SimulateEthSimpleTransfer, SimulateEthCreateContract.
+// Contract call operations work as the future operations of SimulateEthCreateContract.
+func WeightedOperations(
+	appParams simtypes.AppParams, cdc codec.JSONCodec, ak types.AccountKeeper, k *keeper.Keeper,
+) simulation.WeightedOperations {
+	var (
+		weightMsgEthSimpleTransfer int
+		weightMsgEthCreateContract int
+	)
+
+	appParams.GetOrGenerate(cdc, OpWeightMsgEthSimpleTransfer, &weightMsgEthSimpleTransfer, nil,
+		func(_ *rand.Rand) {
+			weightMsgEthSimpleTransfer = WeightMsgEthSimpleTransfer
+		},
+	)
+
+	appParams.GetOrGenerate(cdc, OpWeightMsgEthCreateContract, &weightMsgEthCreateContract, nil,
+		func(_ *rand.Rand) {
+			weightMsgEthCreateContract = WeightMsgEthCreateContract
+		},
+	)
+
+	return simulation.WeightedOperations{
+		simulation.NewWeightedOperation(
+			weightMsgEthSimpleTransfer,
+			SimulateEthSimpleTransfer(ak, k),
+		),
+		simulation.NewWeightedOperation(
+			weightMsgEthCreateContract,
+			SimulateEthCreateContract(ak, k),
+		),
+	}
+}
+
+// SimulateEthSimpleTransfer simulate simple eth account transferring gas token.
+// It randomly choose sender, recipient and transferable amount.
+// Other tx details like nonce, gasprice, gaslimit are calculated to get valid value.
+func SimulateEthSimpleTransfer(ak types.AccountKeeper, k *keeper.Keeper) simtypes.Operation {
+	return func(
+		r *rand.Rand, bapp *baseapp.BaseApp, ctx sdk.Context, accs []simtypes.Account, chainID string,
+	) (simtypes.OperationMsg, []simtypes.FutureOperation, error) {
+		simAccount, _ := simtypes.RandomAcc(r, accs)
+		var recipient simtypes.Account
+		if r.Intn(2) == 1 {
+			recipient, _ = simtypes.RandomAcc(r, accs)
+		} else {
+			recipient = simtypes.RandomAccounts(r, 1)[0]
+		}
+		from := common.BytesToAddress(simAccount.Address)
+		to := common.BytesToAddress(recipient.Address)
+
+		simulateContext := &simulateContext{ctx, bapp, r, k}
+
+		return SimulateEthTx(simulateContext, &from, &to, nil, (*hexutil.Bytes)(&[]byte{}), simAccount.PrivKey, nil)
+	}
+}
+
+// SimulateEthCreateContract simulate create an ERC20 contract.
+// It makes operationSimulateEthCallContract the future operations of SimulateEthCreateContract to ensure valid contract call.
+func SimulateEthCreateContract(ak types.AccountKeeper, k *keeper.Keeper) simtypes.Operation {
+	return func(
+		r *rand.Rand, bapp *baseapp.BaseApp, ctx sdk.Context, accs []simtypes.Account, chainID string,
+	) (simtypes.OperationMsg, []simtypes.FutureOperation, error) {
+		simAccount, _ := simtypes.RandomAcc(r, accs)
+
+		from := common.BytesToAddress(simAccount.Address)
+		nonce := k.GetNonce(ctx, from)
+
+		ctorArgs, err := types.ERC20Contract.ABI.Pack("", from, sdk.NewIntWithDecimal(1000, 18).BigInt())
+		if err != nil {
+			return simtypes.NoOpMsg(types.ModuleName, types.TypeMsgEthereumTx, "can not pack owner and supply"), nil, err
+		}
+		data := types.ERC20Contract.Bin
+		data = append(data, ctorArgs...)
+
+		simulateContext := &simulateContext{ctx, bapp, r, k}
+
+		fops := make([]simtypes.FutureOperation, 1)
+		whenCall := ctx.BlockHeader().Time.Add(time.Duration(r.Intn(maxWaitSeconds)+1) * time.Second)
+		contractAddr := crypto.CreateAddress(from, nonce)
+		var tokenReceipient simtypes.Account
+		if r.Intn(2) == 1 {
+			tokenReceipient, _ = simtypes.RandomAcc(r, accs)
+		} else {
+			tokenReceipient = simtypes.RandomAccounts(r, 1)[0]
+		}
+		receipientAddr := common.BytesToAddress(tokenReceipient.Address)
+		fops[0] = simtypes.FutureOperation{
+			BlockTime: whenCall,
+			Op:        operationSimulateEthCallContract(k, &contractAddr, &receipientAddr, nil),
+		}
+		return SimulateEthTx(simulateContext, &from, nil, nil, (*hexutil.Bytes)(&data), simAccount.PrivKey, fops)
+	}
+}
+
+// operationSimulateEthCallContract simulate calling an contract.
+// It is always calling an ERC20 contract.
+func operationSimulateEthCallContract(k *keeper.Keeper, contractAddr, to *common.Address, amount *big.Int) simtypes.Operation {
+	return func(
+		r *rand.Rand, bapp *baseapp.BaseApp, ctx sdk.Context, accs []simtypes.Account, chainID string,
+	) (simtypes.OperationMsg, []simtypes.FutureOperation, error) {
+		simAccount, _ := simtypes.RandomAcc(r, accs)
+
+		from := common.BytesToAddress(simAccount.Address)
+
+		ctorArgs, err := types.ERC20Contract.ABI.Pack("transfer", to, amount)
+		if err != nil {
+			return simtypes.NoOpMsg(types.ModuleName, types.TypeMsgEthereumTx, "can not pack method and args"), nil, err
+		}
+		data := types.ERC20Contract.Bin
+		data = append(data, ctorArgs...)
+
+		simulateContext := &simulateContext{ctx, bapp, r, k}
+
+		return SimulateEthTx(simulateContext, &from, contractAddr, nil, (*hexutil.Bytes)(&data), simAccount.PrivKey, nil)
+	}
+}
+
+// SimulateEthTx creates valid ethereum tx and pack it as cosmos tx, and deliver it.
+func SimulateEthTx(
+	ctx *simulateContext, from, to *common.Address, amount *big.Int, data *hexutil.Bytes, prv cryptotypes.PrivKey, fops []simtypes.FutureOperation,
+) (simtypes.OperationMsg, []simtypes.FutureOperation, error) {
+	ethTx, err := CreateRandomValidEthTx(ctx, from, nil, nil, data)
+	if err == ErrNoEnoughBalance {
+		return simtypes.NoOpMsg(types.ModuleName, types.TypeMsgEthereumTx, "no enough balance"), nil, nil
+	}
+	if err != nil {
+		return simtypes.NoOpMsg(types.ModuleName, types.TypeMsgEthereumTx, "can not create valid eth tx"), nil, err
+	}
+
+	txConfig := encoding.MakeConfig(module.NewBasicManager()).TxConfig
+	txBuilder := txConfig.NewTxBuilder()
+	signedTx, err := GetSignedTx(ctx, txBuilder, ethTx, prv)
+	if err != nil {
+		return simtypes.NoOpMsg(types.ModuleName, types.TypeMsgEthereumTx, "can not sign ethereum tx"), nil, err
+	}
+
+	_, _, err = ctx.bapp.Deliver(txConfig.TxEncoder(), signedTx)
+	if err != nil {
+		return simtypes.NoOpMsg(types.ModuleName, types.TypeMsgEthereumTx, "failed to deliver tx"), nil, err
+	}
+
+	return simtypes.OperationMsg{}, fops, nil
+}
+
+// CreateRandomValidEthTx create the ethereum tx with valid random values
+func CreateRandomValidEthTx(ctx *simulateContext, from, to *common.Address, amount *big.Int, data *hexutil.Bytes) (ethTx *types.MsgEthereumTx, err error) {
+	estimateGas, err := EstimateGas(ctx, from, to, data)
+	if err != nil {
+		return nil, err
+	}
+	gasLimit := estimateGas + uint64(ctx.rand.Intn(int(sdktx.MaxGasWanted-estimateGas)))
+	ethChainID := ctx.keeper.ChainID()
+	chainConfig := ctx.keeper.GetParams(ctx.context).ChainConfig.EthereumConfig(ethChainID)
+	gasPrice := ctx.keeper.BaseFee(ctx.context, chainConfig)
+	gasFeeCap := new(big.Int).Add(gasPrice, big.NewInt(int64(ctx.rand.Int())))
+	gasTipCap := big.NewInt(int64(ctx.rand.Int()))
+	nonce := ctx.keeper.GetNonce(ctx.context, *from)
+
+	if amount == nil {
+		amount, err = RandomTransferableAmount(ctx, *from, gasLimit, gasFeeCap)
+		if err != nil {
+			return nil, err
+		}
+	}
+
+	ethTx = types.NewTx(ethChainID, nonce, to, amount, gasLimit, gasPrice, gasFeeCap, gasTipCap, *data, nil)
+	ethTx.From = from.String()
+	return ethTx, nil
+}
+
+// EstimateGas estimates the gas used by quering the keeper.
+func EstimateGas(ctx *simulateContext, from, to *common.Address, data *hexutil.Bytes) (gas uint64, err error) {
+	args, err := json.Marshal(&types.TransactionArgs{To: to, From: from, Data: data})
+	if err != nil {
+		return 0, err
+	}
+
+	res, err := ctx.keeper.EstimateGas(sdk.WrapSDKContext(ctx.context), &types.EthCallRequest{
+		Args:   args,
+		GasCap: config.DefaultGasCap,
+	})
+	if err != nil {
+		return 0, err
+	}
+	return res.Gas, nil
+}
+
+// RandomTransferableAmount generates a random valid transferable amount.
+// Transferable amount is between the range [0, spendable), spendable = balance - gasFeeCap * GasLimit.
+func RandomTransferableAmount(ctx *simulateContext, address common.Address, gasLimit uint64, gasFeeCap *big.Int) (amount *big.Int, err error) {
+	balance := ctx.keeper.GetBalance(ctx.context, address)
+	feeLimit := new(big.Int).Mul(gasFeeCap, big.NewInt(int64(gasLimit)))
+	if (feeLimit.Cmp(balance)) > 0 {
+		return nil, ErrNoEnoughBalance
+	}
+	spendable := new(big.Int).Sub(balance, feeLimit)
+	if spendable.Cmp(big.NewInt(0)) == 0 {
+		amount = new(big.Int).Set(spendable)
+		return amount, nil
+	}
+	simAmount, err := simtypes.RandPositiveInt(ctx.rand, sdk.NewIntFromBigInt(spendable))
+	if err != nil {
+		return nil, err
+	}
+	amount = simAmount.BigInt()
+	return amount, nil
+}
+
+// GetSignedTx sign the ethereum tx and packs it as a signing.Tx .
+func GetSignedTx(ctx *simulateContext, txBuilder client.TxBuilder, msg *types.MsgEthereumTx, prv cryptotypes.PrivKey) (signedTx signing.Tx, err error) {
+	builder, ok := txBuilder.(tx.ExtensionOptionsTxBuilder)
+	if !ok {
+		return nil, fmt.Errorf("can not initiate ExtensionOptionsTxBuilder")
+	}
+	option, err := codectypes.NewAnyWithValue(&types.ExtensionOptionsEthereumTx{})
+	if err != nil {
+		return nil, err
+	}
+	builder.SetExtensionOptions(option)
+
+	if err := msg.Sign(ethtypes.LatestSignerForChainID(ctx.keeper.ChainID()), tests.NewSigner(prv)); err != nil {
+		return nil, err
+	}
+
+	if err = builder.SetMsgs(msg); err != nil {
+		return nil, err
+	}
+
+	txData, err := types.UnpackTxData(msg.Data)
+	if err != nil {
+		return nil, err
+	}
+
+	fees := sdk.NewCoins(sdk.NewCoin(ctx.keeper.GetParams(ctx.context).EvmDenom, sdk.NewIntFromBigInt(txData.Fee())))
+	builder.SetFeeAmount(fees)
+	builder.SetGasLimit(msg.GetGas())
+
+	signedTx = builder.GetTx()
+	return signedTx, nil
+}

x/evm/simulation/params.go

@@ -0,0 +1,28 @@
+package simulation
+
+// DONTCOVER
+
+import (
+	"fmt"
+	"math/rand"
+
+	simtypes "github.com/cosmos/cosmos-sdk/types/simulation"
+	"github.com/cosmos/cosmos-sdk/x/simulation"
+	"github.com/tharsis/ethermint/x/evm/types"
+)
+
+const (
+	keyExtraEIPs = "ExtraEIPs"
+)
+
+// ParamChanges defines the parameters that can be modified by param change proposals
+// on the simulation.
+func ParamChanges(r *rand.Rand) []simtypes.ParamChange {
+	return []simtypes.ParamChange{
+		simulation.NewSimParamChange(types.ModuleName, keyExtraEIPs,
+			func(r *rand.Rand) string {
+				return fmt.Sprintf("\"%d\"", genExtraEIPs(r))
+			},
+		),
+	}
+}