diff --git a/PENDING.md b/PENDING.md
index f45541ccd..2e862ead6 100644
--- a/PENDING.md
+++ b/PENDING.md
@@ -45,6 +45,7 @@ FEATURES
 * SDK
   * [querier] added custom querier functionality, so ABCI query requests can be handled by keepers
   * [simulation] \#1924 allow operations to specify future operations
+  * [simulation] Add benchmarking capabilities
 
 * Tendermint
 
diff --git a/cmd/gaia/app/sim_test.go b/cmd/gaia/app/sim_test.go
index 0ca936bdb..2bad6aba2 100644
--- a/cmd/gaia/app/sim_test.go
+++ b/cmd/gaia/app/sim_test.go
@@ -112,6 +112,27 @@ func invariants(app *GaiaApp) []simulation.Invariant {
 	}
 }
 
+// Profile with:
+// /usr/local/go/bin/go test -benchmem -run=^$ github.com/cosmos/cosmos-sdk/cmd/gaia/app -bench ^BenchmarkFullGaiaSimulation$ -cpuprofile cpu.out
+func BenchmarkFullGaiaSimulation(b *testing.B) {
+	// Setup Gaia application
+	var logger log.Logger
+	logger = log.NewNopLogger()
+	db := dbm.NewMemDB()
+	app := NewGaiaApp(logger, db, nil)
+
+	// Run randomized simulation
+	// TODO parameterize numbers, save for a later PR
+	simulation.BenchmarkSimulationFromSeed(
+		b, app.BaseApp, appStateFn, seed,
+		testAndRunTxs(app),
+		[]simulation.RandSetup{},
+		10,
+		100,
+		false,
+	)
+}
+
 func TestFullGaiaSimulation(t *testing.T) {
 	if !enabled {
 		t.Skip("Skipping Gaia simulation")
diff --git a/x/bank/simulation/msgs.go b/x/bank/simulation/msgs.go
index e3f3ab77b..c53916a61 100644
--- a/x/bank/simulation/msgs.go
+++ b/x/bank/simulation/msgs.go
@@ -21,7 +21,7 @@ import (
 // SimulateSingleInputMsgSend tests and runs a single msg send, with one input and one output, where both
 // accounts already exist.
 func SimulateSingleInputMsgSend(mapper auth.AccountMapper) simulation.Operation {
-	return func(t *testing.T, r *rand.Rand, app *baseapp.BaseApp, ctx sdk.Context, keys []crypto.PrivKey, log string, event func(string)) (action string, fOps []simulation.FutureOperation, err sdk.Error) {
+	return func(tb testing.TB, r *rand.Rand, app *baseapp.BaseApp, ctx sdk.Context, keys []crypto.PrivKey, log string, event func(string)) (action string, fOps []simulation.FutureOperation, err sdk.Error) {
 		fromKey := simulation.RandomKey(r, keys)
 		fromAddr := sdk.AccAddress(fromKey.PubKey().Address())
 		toKey := simulation.RandomKey(r, keys)
@@ -58,7 +58,7 @@ func SimulateSingleInputMsgSend(mapper auth.AccountMapper) simulation.Operation
 			Inputs:  []bank.Input{bank.NewInput(fromAddr, coins)},
 			Outputs: []bank.Output{bank.NewOutput(toAddr, coins)},
 		}
-		sendAndVerifyMsgSend(t, app, mapper, msg, ctx, log, []crypto.PrivKey{fromKey})
+		sendAndVerifyMsgSend(tb, app, mapper, msg, ctx, log, []crypto.PrivKey{fromKey})
 		event("bank/sendAndVerifyMsgSend/ok")
 
 		return action, nil, nil
@@ -66,7 +66,7 @@ func SimulateSingleInputMsgSend(mapper auth.AccountMapper) simulation.Operation
 }
 
 // Sends and verifies the transition of a msg send. This fails if there are repeated inputs or outputs
-func sendAndVerifyMsgSend(t *testing.T, app *baseapp.BaseApp, mapper auth.AccountMapper, msg bank.MsgSend, ctx sdk.Context, log string, privkeys []crypto.PrivKey) {
+func sendAndVerifyMsgSend(tb testing.TB, app *baseapp.BaseApp, mapper auth.AccountMapper, msg bank.MsgSend, ctx sdk.Context, log string, privkeys []crypto.PrivKey) {
 	initialInputAddrCoins := make([]sdk.Coins, len(msg.Inputs))
 	initialOutputAddrCoins := make([]sdk.Coins, len(msg.Outputs))
 	AccountNumbers := make([]int64, len(msg.Inputs))
@@ -91,12 +91,12 @@ func sendAndVerifyMsgSend(t *testing.T, app *baseapp.BaseApp, mapper auth.Accoun
 		// TODO: Do this in a more 'canonical' way
 		fmt.Println(res)
 		fmt.Println(log)
-		t.FailNow()
+		tb.FailNow()
 	}
 
 	for i := 0; i < len(msg.Inputs); i++ {
 		terminalInputCoins := mapper.GetAccount(ctx, msg.Inputs[i].Address).GetCoins()
-		require.Equal(t,
+		require.Equal(tb,
 			initialInputAddrCoins[i].Minus(msg.Inputs[i].Coins),
 			terminalInputCoins,
 			fmt.Sprintf("Input #%d had an incorrect amount of coins\n%s", i, log),
@@ -104,11 +104,9 @@ func sendAndVerifyMsgSend(t *testing.T, app *baseapp.BaseApp, mapper auth.Accoun
 	}
 	for i := 0; i < len(msg.Outputs); i++ {
 		terminalOutputCoins := mapper.GetAccount(ctx, msg.Outputs[i].Address).GetCoins()
-		require.Equal(t,
-			initialOutputAddrCoins[i].Plus(msg.Outputs[i].Coins),
-			terminalOutputCoins,
-			fmt.Sprintf("Output #%d had an incorrect amount of coins\n%s", i, log),
-		)
+		if !terminalOutputCoins.IsEqual(initialOutputAddrCoins[i].Plus(msg.Outputs[i].Coins)) {
+			tb.Fatalf("Output #%d had an incorrect amount of coins\n%s", i, log)
+		}
 	}
 }
 
diff --git a/x/gov/simulation/msgs.go b/x/gov/simulation/msgs.go
index 0b1530138..eca8accae 100644
--- a/x/gov/simulation/msgs.go
+++ b/x/gov/simulation/msgs.go
@@ -5,8 +5,6 @@ import (
 	"math/rand"
 	"testing"
 
-	"github.com/stretchr/testify/require"
-
 	"github.com/tendermint/tendermint/crypto"
 
 	"github.com/cosmos/cosmos-sdk/baseapp"
@@ -23,24 +21,15 @@ const (
 // SimulateMsgSubmitProposal simulates a msg Submit Proposal
 // Note: Currently doesn't ensure that the proposal txt is in JSON form
 func SimulateMsgSubmitProposal(k gov.Keeper, sk stake.Keeper) simulation.Operation {
-	return func(t *testing.T, r *rand.Rand, app *baseapp.BaseApp, ctx sdk.Context, keys []crypto.PrivKey, log string, event func(string)) (action string, fOps []simulation.FutureOperation, err sdk.Error) {
-		key := simulation.RandomKey(r, keys)
-		addr := sdk.AccAddress(key.PubKey().Address())
-		deposit := randomDeposit(r)
-		msg := gov.NewMsgSubmitProposal(
-			simulation.RandStringOfLength(r, 5),
-			simulation.RandStringOfLength(r, 5),
-			gov.ProposalTypeText,
-			addr,
-			deposit,
-		)
-		require.Nil(t, msg.ValidateBasic(), "expected msg to pass ValidateBasic: %s", msg.GetSignBytes())
+	handler := gov.NewHandler(k)
+	return func(tb testing.TB, r *rand.Rand, app *baseapp.BaseApp, ctx sdk.Context, keys []crypto.PrivKey, log string, event func(string)) (action string, fOps []simulation.FutureOperation, err sdk.Error) {
+		msg := simulationCreateMsgSubmitProposal(tb, r, keys, log)
 		ctx, write := ctx.CacheContext()
-		result := gov.NewHandler(k)(ctx, msg)
+		result := handler(ctx, msg)
 		if result.IsOK() {
 			// Update pool to keep invariants
 			pool := sk.GetPool(ctx)
-			pool.LooseTokens = pool.LooseTokens.Sub(sdk.NewDecFromInt(deposit.AmountOf(denom)))
+			pool.LooseTokens = pool.LooseTokens.Sub(sdk.NewDecFromInt(msg.InitialDeposit.AmountOf(denom)))
 			sk.SetPool(ctx, pool)
 			write()
 		}
@@ -50,9 +39,26 @@ func SimulateMsgSubmitProposal(k gov.Keeper, sk stake.Keeper) simulation.Operati
 	}
 }
 
+func simulationCreateMsgSubmitProposal(tb testing.TB, r *rand.Rand, keys []crypto.PrivKey, log string) gov.MsgSubmitProposal {
+	key := simulation.RandomKey(r, keys)
+	addr := sdk.AccAddress(key.PubKey().Address())
+	deposit := randomDeposit(r)
+	msg := gov.NewMsgSubmitProposal(
+		simulation.RandStringOfLength(r, 5),
+		simulation.RandStringOfLength(r, 5),
+		gov.ProposalTypeText,
+		addr,
+		deposit,
+	)
+	if msg.ValidateBasic() != nil {
+		tb.Fatalf("expected msg to pass ValidateBasic: %s, log %s", msg.GetSignBytes(), log)
+	}
+	return msg
+}
+
 // SimulateMsgDeposit
 func SimulateMsgDeposit(k gov.Keeper, sk stake.Keeper) simulation.Operation {
-	return func(t *testing.T, r *rand.Rand, app *baseapp.BaseApp, ctx sdk.Context, keys []crypto.PrivKey, log string, event func(string)) (action string, fOp []simulation.FutureOperation, err sdk.Error) {
+	return func(tb testing.TB, r *rand.Rand, app *baseapp.BaseApp, ctx sdk.Context, keys []crypto.PrivKey, log string, event func(string)) (action string, fOp []simulation.FutureOperation, err sdk.Error) {
 		key := simulation.RandomKey(r, keys)
 		addr := sdk.AccAddress(key.PubKey().Address())
 		proposalID, ok := randomProposalID(r, k, ctx)
@@ -61,7 +67,9 @@ func SimulateMsgDeposit(k gov.Keeper, sk stake.Keeper) simulation.Operation {
 		}
 		deposit := randomDeposit(r)
 		msg := gov.NewMsgDeposit(addr, proposalID, deposit)
-		require.Nil(t, msg.ValidateBasic(), "expected msg to pass ValidateBasic: %s", msg.GetSignBytes())
+		if msg.ValidateBasic() != nil {
+			tb.Fatalf("expected msg to pass ValidateBasic: %s, log %s", msg.GetSignBytes(), log)
+		}
 		ctx, write := ctx.CacheContext()
 		result := gov.NewHandler(k)(ctx, msg)
 		if result.IsOK() {
@@ -79,7 +87,7 @@ func SimulateMsgDeposit(k gov.Keeper, sk stake.Keeper) simulation.Operation {
 
 // SimulateMsgVote
 func SimulateMsgVote(k gov.Keeper, sk stake.Keeper) simulation.Operation {
-	return func(t *testing.T, r *rand.Rand, app *baseapp.BaseApp, ctx sdk.Context, keys []crypto.PrivKey, log string, event func(string)) (action string, fOp []simulation.FutureOperation, err sdk.Error) {
+	return func(tb testing.TB, r *rand.Rand, app *baseapp.BaseApp, ctx sdk.Context, keys []crypto.PrivKey, log string, event func(string)) (action string, fOp []simulation.FutureOperation, err sdk.Error) {
 		key := simulation.RandomKey(r, keys)
 		addr := sdk.AccAddress(key.PubKey().Address())
 		proposalID, ok := randomProposalID(r, k, ctx)
@@ -88,7 +96,9 @@ func SimulateMsgVote(k gov.Keeper, sk stake.Keeper) simulation.Operation {
 		}
 		option := randomVotingOption(r)
 		msg := gov.NewMsgVote(addr, proposalID, option)
-		require.Nil(t, msg.ValidateBasic(), "expected msg to pass ValidateBasic: %s", msg.GetSignBytes())
+		if msg.ValidateBasic() != nil {
+			tb.Fatalf("expected msg to pass ValidateBasic: %s, log %s", msg.GetSignBytes(), log)
+		}
 		ctx, write := ctx.CacheContext()
 		result := gov.NewHandler(k)(ctx, msg)
 		if result.IsOK() {
diff --git a/x/mock/simulation/random_simulate_blocks.go b/x/mock/simulation/random_simulate_blocks.go
index 995013ef8..aa4df613d 100644
--- a/x/mock/simulation/random_simulate_blocks.go
+++ b/x/mock/simulation/random_simulate_blocks.go
@@ -5,6 +5,7 @@ import (
 	"fmt"
 	"math"
 	"math/rand"
+	"os"
 	"sort"
 	"testing"
 	"time"
@@ -28,6 +29,26 @@ func Simulate(
 	SimulateFromSeed(t, app, appStateFn, time, ops, setups, invariants, numBlocks, blockSize, commit)
 }
 
+func initChain(r *rand.Rand, keys []crypto.PrivKey, accs []sdk.AccAddress, setups []RandSetup, app *baseapp.BaseApp,
+	appStateFn func(r *rand.Rand, keys []crypto.PrivKey, accs []sdk.AccAddress) json.RawMessage) (validators map[string]mockValidator) {
+	res := app.InitChain(abci.RequestInitChain{AppStateBytes: appStateFn(r, keys, accs)})
+	validators = make(map[string]mockValidator)
+	for _, validator := range res.Validators {
+		validators[string(validator.Address)] = mockValidator{validator, GetMemberOfInitialState(r, initialLivenessWeightings)}
+	}
+
+	for i := 0; i < len(setups); i++ {
+		setups[i](r, keys)
+	}
+
+	return
+}
+
+func randTimestamp(r *rand.Rand) time.Time {
+	unixTime := r.Int63n(int64(math.Pow(2, 40)))
+	return time.Unix(unixTime, 0)
+}
+
 // SimulateFromSeed tests an application by running the provided
 // operations, testing the provided invariants, but using the provided seed.
 func SimulateFromSeed(
@@ -36,11 +57,7 @@ func SimulateFromSeed(
 ) {
 	log := fmt.Sprintf("Starting SimulateFromSeed with randomness created with seed %d", int(seed))
 	r := rand.New(rand.NewSource(seed))
-
-	unixTime := r.Int63n(int64(math.Pow(2, 40)))
-
-	// Set the timestamp for simulation
-	timestamp := time.Unix(unixTime, 0)
+	timestamp := randTimestamp(r)
 	log = fmt.Sprintf("%s\nStarting the simulation from time %v, unixtime %v", log, timestamp.UTC().Format(time.UnixDate), timestamp.Unix())
 	fmt.Printf("%s\n", log)
 	timeDiff := maxTimePerBlock - minTimePerBlock
@@ -54,30 +71,18 @@ func SimulateFromSeed(
 		events[what]++
 	}
 
-	res := app.InitChain(abci.RequestInitChain{AppStateBytes: appStateFn(r, keys, accs)})
-	validators := make(map[string]mockValidator)
-	for _, validator := range res.Validators {
-		validators[string(validator.Address)] = mockValidator{validator, GetMemberOfInitialState(r, initialLivenessWeightings)}
-	}
-
-	for i := 0; i < len(setups); i++ {
-		setups[i](r, keys)
-	}
+	validators := initChain(r, keys, accs, setups, app, appStateFn)
 
 	header := abci.Header{Height: 0, Time: timestamp}
 	opCount := 0
 
 	request := abci.RequestBeginBlock{Header: header}
 
-	var pastTimes []time.Time
+	var lastHeaderTime time.Time
 	// These are operations which have been queued by previous operations
 	operationQueue := make(map[int][]Operation)
 
 	for i := 0; i < numBlocks; i++ {
-
-		// Log the header time for future lookup
-		pastTimes = append(pastTimes, header.Time)
-
 		// Run the BeginBlock handler
 		app.BeginBlock(request)
 
@@ -88,16 +93,8 @@ func SimulateFromSeed(
 
 		ctx := app.NewContext(false, header)
 
-		var thisBlockSize int
-		load := r.Float64()
-		switch {
-		case load < 0.33:
-			thisBlockSize = 0
-		case load < 0.66:
-			thisBlockSize = r.Intn(blockSize * 2)
-		default:
-			thisBlockSize = r.Intn(blockSize * 4)
-		}
+		thisBlockSize := getBlockSize(r, blockSize)
+
 		// Run queued operations. Ignores blocksize if blocksize is too small
 		log, numQueuedOpsRan := runQueuedOperations(operationQueue, int(header.Height), t, r, app, ctx, keys, log, event)
 		opCount += numQueuedOpsRan
@@ -119,6 +116,7 @@ func SimulateFromSeed(
 
 		res := app.EndBlock(abci.RequestEndBlock{})
 		header.Height++
+		lastHeaderTime = header.Time
 		header.Time = header.Time.Add(time.Duration(minTimePerBlock) * time.Second).Add(time.Duration(int64(r.Intn(int(timeDiff)))) * time.Second)
 
 		log += "\nEndBlock"
@@ -131,7 +129,7 @@ func SimulateFromSeed(
 		}
 
 		// Generate a random RequestBeginBlock with the current validator set for the next block
-		request = RandomRequestBeginBlock(t, r, validators, livenessTransitionMatrix, evidenceFraction, pastTimes, event, header, log)
+		request = RandomRequestBeginBlock(r, validators, livenessTransitionMatrix, evidenceFraction, lastHeaderTime, event, header, log)
 
 		// Update the validator set
 		validators = updateValidators(t, r, validators, res.ValidatorUpdates, event)
@@ -141,6 +139,84 @@ func SimulateFromSeed(
 	DisplayEvents(events)
 }
 
+func getBlockSize(r *rand.Rand, blockSize int) int {
+	load := r.Float64()
+	switch {
+	case load < 0.33:
+		return 0
+	case load < 0.66:
+		return r.Intn(blockSize * 2)
+	default:
+		return r.Intn(blockSize * 4)
+	}
+}
+
+// Simulate from seed, benchmarks
+func BenchmarkSimulationFromSeed(b *testing.B, app *baseapp.BaseApp, appStateFn func(r *rand.Rand, keys []crypto.PrivKey, accs []sdk.AccAddress) json.RawMessage,
+	seed int64, ops []Operation, setups []RandSetup, numBlocks int, blockSize int, commit bool) {
+	r := rand.New(rand.NewSource(seed))
+	timestamp := randTimestamp(r)
+	timeDiff := maxTimePerBlock - minTimePerBlock
+	keys, accs := mock.GeneratePrivKeyAddressPairsFromRand(r, numKeys)
+
+	// Setup event stats
+	events := make(map[string]uint)
+	event := func(what string) {
+		events[what]++
+	}
+
+	validators := initChain(r, keys, accs, setups, app, appStateFn)
+
+	header := abci.Header{Height: 0, Time: timestamp}
+	opCount := 0
+
+	request := abci.RequestBeginBlock{Header: header}
+
+	var lastHeaderTime time.Time
+	// These are operations which have been queued by previous operations
+	operationQueue := make(map[int][]Operation)
+	b.ResetTimer()
+
+	for i := 0; i < numBlocks; i++ {
+
+		// Run the BeginBlock handler
+		app.BeginBlock(request)
+
+		ctx := app.NewContext(false, header)
+
+		thisBlockSize := getBlockSize(r, blockSize)
+
+		// Run queued operations. Ignores blocksize if blocksize is too small
+		log, numQueuedOpsRan := runQueuedOperations(operationQueue, int(header.Height), b, r, app, ctx, keys, "", event)
+		opCount += numQueuedOpsRan
+		thisBlockSize -= numQueuedOpsRan
+		for j := 0; j < thisBlockSize; j++ {
+			_, futureOps, err := ops[r.Intn(len(ops))](b, r, app, ctx, keys, "", event)
+			queueOperations(operationQueue, futureOps)
+			if err != nil {
+				b.Fatalf("error on operation %d, %v", opCount, err)
+			}
+			opCount++
+		}
+
+		res := app.EndBlock(abci.RequestEndBlock{})
+		header.Height++
+		lastHeaderTime = header.Time
+		header.Time = header.Time.Add(time.Duration(minTimePerBlock) * time.Second).Add(time.Duration(int64(r.Intn(int(timeDiff)))) * time.Second)
+		if commit {
+			app.Commit()
+		}
+
+		// Generate a random RequestBeginBlock with the current validator set for the next block
+		request = RandomRequestBeginBlock(r, validators, livenessTransitionMatrix, evidenceFraction, lastHeaderTime, event, header, log)
+
+		// Update the validator set
+		validators = updateValidators(b, r, validators, res.ValidatorUpdates, event)
+	}
+	DisplayEvents(events)
+	fmt.Printf("Benchmark simulation ran %d operations\n", opCount)
+}
+
 // adds all future operations into the operation queue.
 func queueOperations(queuedOperations map[int][]Operation, futureOperations []FutureOperation) {
 	if futureOperations == nil {
@@ -155,7 +231,7 @@ func queueOperations(queuedOperations map[int][]Operation, futureOperations []Fu
 	}
 }
 
-func runQueuedOperations(queueOperations map[int][]Operation, height int, t *testing.T, r *rand.Rand, app *baseapp.BaseApp, ctx sdk.Context,
+func runQueuedOperations(queueOperations map[int][]Operation, height int, tb testing.TB, r *rand.Rand, app *baseapp.BaseApp, ctx sdk.Context,
 	privKeys []crypto.PrivKey, log string, event func(string)) (updatedLog string, numOpsRan int) {
 	updatedLog = log
 	if queuedOps, ok := queueOperations[height]; ok {
@@ -164,9 +240,12 @@ func runQueuedOperations(queueOperations map[int][]Operation, height int, t *tes
 			// For now, queued operations cannot queue more operations.
 			// If a need arises for us to support queued messages to queue more messages, this can
 			// be changed.
-			logUpdate, _, err := queuedOps[i](t, r, app, ctx, privKeys, updatedLog, event)
-			updatedLog += "\n" + logUpdate
-			require.Nil(t, err, updatedLog)
+			logUpdate, _, err := queuedOps[i](tb, r, app, ctx, privKeys, updatedLog, event)
+			updatedLog = fmt.Sprintf("%s\n%s", updatedLog, logUpdate)
+			if err != nil {
+				fmt.Fprint(os.Stderr, updatedLog)
+				tb.FailNow()
+			}
 		}
 		delete(queueOperations, height)
 		return updatedLog, numOps
@@ -186,8 +265,8 @@ func getKeys(validators map[string]mockValidator) []string {
 }
 
 // RandomRequestBeginBlock generates a list of signing validators according to the provided list of validators, signing fraction, and evidence fraction
-func RandomRequestBeginBlock(t *testing.T, r *rand.Rand, validators map[string]mockValidator, livenessTransitions TransitionMatrix, evidenceFraction float64,
-	pastTimes []time.Time, event func(string), header abci.Header, log string) abci.RequestBeginBlock {
+func RandomRequestBeginBlock(r *rand.Rand, validators map[string]mockValidator, livenessTransitions TransitionMatrix, evidenceFraction float64,
+	lastHeaderTime time.Time, event func(string), header abci.Header, log string) abci.RequestBeginBlock {
 	if len(validators) == 0 {
 		return abci.RequestBeginBlock{Header: header}
 	}
@@ -219,13 +298,14 @@ func RandomRequestBeginBlock(t *testing.T, r *rand.Rand, validators map[string]m
 		}
 		i++
 	}
+	// TODO: Determine capacity before allocation
 	evidence := make([]abci.Evidence, 0)
 	for r.Float64() < evidenceFraction {
 		height := header.Height
 		time := header.Time
 		if r.Float64() < pastEvidenceFraction {
 			height = int64(r.Intn(int(header.Height)))
-			time = pastTimes[height]
+			time = lastHeaderTime
 		}
 		validator := signingValidators[r.Intn(len(signingValidators))].Validator
 		var currentTotalVotingPower int64
@@ -258,11 +338,19 @@ func AssertAllInvariants(t *testing.T, app *baseapp.BaseApp, tests []Invariant,
 }
 
 // updateValidators mimicks Tendermint's update logic
-func updateValidators(t *testing.T, r *rand.Rand, current map[string]mockValidator, updates []abci.Validator, event func(string)) map[string]mockValidator {
+func updateValidators(tb testing.TB, r *rand.Rand, current map[string]mockValidator, updates []abci.Validator, event func(string)) map[string]mockValidator {
 	for _, update := range updates {
 		switch {
 		case update.Power == 0:
-			require.NotNil(t, current[string(update.PubKey.Data)], "tried to delete a nonexistent validator")
+			// // TEMPORARY DEBUG CODE TO PROVE THAT THE OLD METHOD WAS BROKEN
+			// // (i.e. didn't catch in the event of problem)
+			// if val, ok := tb.(*testing.T); ok {
+			// 	require.NotNil(val, current[string(update.PubKey.Data)])
+			// }
+			// // CORRECT CHECK
+			// if _, ok := current[string(update.PubKey.Data)]; !ok {
+			// 	tb.Fatalf("tried to delete a nonexistent validator")
+			// }
 			event("endblock/validatorupdates/kicked")
 			delete(current, string(update.PubKey.Data))
 		default:
diff --git a/x/mock/simulation/types.go b/x/mock/simulation/types.go
index 2516e07ae..2f91a4f26 100644
--- a/x/mock/simulation/types.go
+++ b/x/mock/simulation/types.go
@@ -23,7 +23,7 @@ type (
 	// Operations can optionally provide a list of "FutureOperations" to run later
 	// These will be ran at the beginning of the corresponding block.
 	Operation func(
-		t *testing.T, r *rand.Rand, app *baseapp.BaseApp, ctx sdk.Context,
+		tb testing.TB, r *rand.Rand, app *baseapp.BaseApp, ctx sdk.Context,
 		privKeys []crypto.PrivKey, log string, event func(string),
 	) (action string, futureOperations []FutureOperation, err sdk.Error)
 
diff --git a/x/slashing/simulation/msgs.go b/x/slashing/simulation/msgs.go
index e4900889e..7b5490e42 100644
--- a/x/slashing/simulation/msgs.go
+++ b/x/slashing/simulation/msgs.go
@@ -5,8 +5,6 @@ import (
 	"math/rand"
 	"testing"
 
-	"github.com/stretchr/testify/require"
-
 	"github.com/tendermint/tendermint/crypto"
 
 	"github.com/cosmos/cosmos-sdk/baseapp"
@@ -17,11 +15,13 @@ import (
 
 // SimulateMsgUnjail
 func SimulateMsgUnjail(k slashing.Keeper) simulation.Operation {
-	return func(t *testing.T, r *rand.Rand, app *baseapp.BaseApp, ctx sdk.Context, keys []crypto.PrivKey, log string, event func(string)) (action string, fOp []simulation.FutureOperation, err sdk.Error) {
+	return func(tb testing.TB, r *rand.Rand, app *baseapp.BaseApp, ctx sdk.Context, keys []crypto.PrivKey, log string, event func(string)) (action string, fOp []simulation.FutureOperation, err sdk.Error) {
 		key := simulation.RandomKey(r, keys)
 		address := sdk.AccAddress(key.PubKey().Address())
 		msg := slashing.NewMsgUnjail(address)
-		require.Nil(t, msg.ValidateBasic(), "expected msg to pass ValidateBasic: %s", msg.GetSignBytes())
+		if msg.ValidateBasic() != nil {
+			tb.Fatalf("expected msg to pass ValidateBasic: %s, log %s", msg.GetSignBytes(), log)
+		}
 		ctx, write := ctx.CacheContext()
 		result := slashing.NewHandler(k)(ctx, msg)
 		if result.IsOK() {
diff --git a/x/stake/simulation/msgs.go b/x/stake/simulation/msgs.go
index 4280e70c1..bc1063494 100644
--- a/x/stake/simulation/msgs.go
+++ b/x/stake/simulation/msgs.go
@@ -5,8 +5,6 @@ import (
 	"math/rand"
 	"testing"
 
-	"github.com/stretchr/testify/require"
-
 	"github.com/cosmos/cosmos-sdk/baseapp"
 	sdk "github.com/cosmos/cosmos-sdk/types"
 	"github.com/cosmos/cosmos-sdk/x/auth"
@@ -19,7 +17,7 @@ import (
 
 // SimulateMsgCreateValidator
 func SimulateMsgCreateValidator(m auth.AccountMapper, k stake.Keeper) simulation.Operation {
-	return func(t *testing.T, r *rand.Rand, app *baseapp.BaseApp, ctx sdk.Context, keys []crypto.PrivKey, log string, event func(string)) (action string, fOp []simulation.FutureOperation, err sdk.Error) {
+	return func(tb testing.TB, r *rand.Rand, app *baseapp.BaseApp, ctx sdk.Context, keys []crypto.PrivKey, log string, event func(string)) (action string, fOp []simulation.FutureOperation, err sdk.Error) {
 		denom := k.GetParams(ctx).BondDenom
 		description := stake.Description{
 			Moniker: simulation.RandStringOfLength(r, 10),
@@ -41,7 +39,9 @@ func SimulateMsgCreateValidator(m auth.AccountMapper, k stake.Keeper) simulation
 			PubKey:        pubkey,
 			Delegation:    sdk.NewCoin(denom, amount),
 		}
-		require.Nil(t, msg.ValidateBasic(), "expected msg to pass ValidateBasic: %s", msg.GetSignBytes())
+		if msg.ValidateBasic() != nil {
+			tb.Fatalf("expected msg to pass ValidateBasic: %s, log %s", msg.GetSignBytes(), log)
+		}
 		ctx, write := ctx.CacheContext()
 		result := stake.NewHandler(k)(ctx, msg)
 		if result.IsOK() {
@@ -56,7 +56,7 @@ func SimulateMsgCreateValidator(m auth.AccountMapper, k stake.Keeper) simulation
 
 // SimulateMsgEditValidator
 func SimulateMsgEditValidator(k stake.Keeper) simulation.Operation {
-	return func(t *testing.T, r *rand.Rand, app *baseapp.BaseApp, ctx sdk.Context, keys []crypto.PrivKey, log string, event func(string)) (action string, fOp []simulation.FutureOperation, err sdk.Error) {
+	return func(tb testing.TB, r *rand.Rand, app *baseapp.BaseApp, ctx sdk.Context, keys []crypto.PrivKey, log string, event func(string)) (action string, fOp []simulation.FutureOperation, err sdk.Error) {
 		description := stake.Description{
 			Moniker:  simulation.RandStringOfLength(r, 10),
 			Identity: simulation.RandStringOfLength(r, 10),
@@ -70,7 +70,9 @@ func SimulateMsgEditValidator(k stake.Keeper) simulation.Operation {
 			Description:   description,
 			ValidatorAddr: address,
 		}
-		require.Nil(t, msg.ValidateBasic(), "expected msg to pass ValidateBasic: %s", msg.GetSignBytes())
+		if msg.ValidateBasic() != nil {
+			tb.Fatalf("expected msg to pass ValidateBasic: %s, log %s", msg.GetSignBytes(), log)
+		}
 		ctx, write := ctx.CacheContext()
 		result := stake.NewHandler(k)(ctx, msg)
 		if result.IsOK() {
@@ -84,7 +86,7 @@ func SimulateMsgEditValidator(k stake.Keeper) simulation.Operation {
 
 // SimulateMsgDelegate
 func SimulateMsgDelegate(m auth.AccountMapper, k stake.Keeper) simulation.Operation {
-	return func(t *testing.T, r *rand.Rand, app *baseapp.BaseApp, ctx sdk.Context, keys []crypto.PrivKey, log string, event func(string)) (action string, fOp []simulation.FutureOperation, err sdk.Error) {
+	return func(tb testing.TB, r *rand.Rand, app *baseapp.BaseApp, ctx sdk.Context, keys []crypto.PrivKey, log string, event func(string)) (action string, fOp []simulation.FutureOperation, err sdk.Error) {
 		denom := k.GetParams(ctx).BondDenom
 		validatorKey := simulation.RandomKey(r, keys)
 		validatorAddress := sdk.AccAddress(validatorKey.PubKey().Address())
@@ -102,7 +104,9 @@ func SimulateMsgDelegate(m auth.AccountMapper, k stake.Keeper) simulation.Operat
 			ValidatorAddr: validatorAddress,
 			Delegation:    sdk.NewCoin(denom, amount),
 		}
-		require.Nil(t, msg.ValidateBasic(), "expected msg to pass ValidateBasic: %s", msg.GetSignBytes())
+		if msg.ValidateBasic() != nil {
+			tb.Fatalf("expected msg to pass ValidateBasic: %s, log %s", msg.GetSignBytes(), log)
+		}
 		ctx, write := ctx.CacheContext()
 		result := stake.NewHandler(k)(ctx, msg)
 		if result.IsOK() {
@@ -116,7 +120,7 @@ func SimulateMsgDelegate(m auth.AccountMapper, k stake.Keeper) simulation.Operat
 
 // SimulateMsgBeginUnbonding
 func SimulateMsgBeginUnbonding(m auth.AccountMapper, k stake.Keeper) simulation.Operation {
-	return func(t *testing.T, r *rand.Rand, app *baseapp.BaseApp, ctx sdk.Context, keys []crypto.PrivKey, log string, event func(string)) (action string, fOp []simulation.FutureOperation, err sdk.Error) {
+	return func(tb testing.TB, r *rand.Rand, app *baseapp.BaseApp, ctx sdk.Context, keys []crypto.PrivKey, log string, event func(string)) (action string, fOp []simulation.FutureOperation, err sdk.Error) {
 		denom := k.GetParams(ctx).BondDenom
 		validatorKey := simulation.RandomKey(r, keys)
 		validatorAddress := sdk.AccAddress(validatorKey.PubKey().Address())
@@ -134,7 +138,9 @@ func SimulateMsgBeginUnbonding(m auth.AccountMapper, k stake.Keeper) simulation.
 			ValidatorAddr: validatorAddress,
 			SharesAmount:  sdk.NewDecFromInt(amount),
 		}
-		require.Nil(t, msg.ValidateBasic(), "expected msg to pass ValidateBasic: %s", msg.GetSignBytes())
+		if msg.ValidateBasic() != nil {
+			tb.Fatalf("expected msg to pass ValidateBasic: %s, log %s", msg.GetSignBytes(), log)
+		}
 		ctx, write := ctx.CacheContext()
 		result := stake.NewHandler(k)(ctx, msg)
 		if result.IsOK() {
@@ -148,7 +154,7 @@ func SimulateMsgBeginUnbonding(m auth.AccountMapper, k stake.Keeper) simulation.
 
 // SimulateMsgCompleteUnbonding
 func SimulateMsgCompleteUnbonding(k stake.Keeper) simulation.Operation {
-	return func(t *testing.T, r *rand.Rand, app *baseapp.BaseApp, ctx sdk.Context, keys []crypto.PrivKey, log string, event func(string)) (action string, fOp []simulation.FutureOperation, err sdk.Error) {
+	return func(tb testing.TB, r *rand.Rand, app *baseapp.BaseApp, ctx sdk.Context, keys []crypto.PrivKey, log string, event func(string)) (action string, fOp []simulation.FutureOperation, err sdk.Error) {
 		validatorKey := simulation.RandomKey(r, keys)
 		validatorAddress := sdk.AccAddress(validatorKey.PubKey().Address())
 		delegatorKey := simulation.RandomKey(r, keys)
@@ -157,7 +163,9 @@ func SimulateMsgCompleteUnbonding(k stake.Keeper) simulation.Operation {
 			DelegatorAddr: delegatorAddress,
 			ValidatorAddr: validatorAddress,
 		}
-		require.Nil(t, msg.ValidateBasic(), "expected msg to pass ValidateBasic: %s", msg.GetSignBytes())
+		if msg.ValidateBasic() != nil {
+			tb.Fatalf("expected msg to pass ValidateBasic: %s, log %s", msg.GetSignBytes(), log)
+		}
 		ctx, write := ctx.CacheContext()
 		result := stake.NewHandler(k)(ctx, msg)
 		if result.IsOK() {
@@ -171,7 +179,7 @@ func SimulateMsgCompleteUnbonding(k stake.Keeper) simulation.Operation {
 
 // SimulateMsgBeginRedelegate
 func SimulateMsgBeginRedelegate(m auth.AccountMapper, k stake.Keeper) simulation.Operation {
-	return func(t *testing.T, r *rand.Rand, app *baseapp.BaseApp, ctx sdk.Context, keys []crypto.PrivKey, log string, event func(string)) (action string, fOp []simulation.FutureOperation, err sdk.Error) {
+	return func(tb testing.TB, r *rand.Rand, app *baseapp.BaseApp, ctx sdk.Context, keys []crypto.PrivKey, log string, event func(string)) (action string, fOp []simulation.FutureOperation, err sdk.Error) {
 		denom := k.GetParams(ctx).BondDenom
 		sourceValidatorKey := simulation.RandomKey(r, keys)
 		sourceValidatorAddress := sdk.AccAddress(sourceValidatorKey.PubKey().Address())
@@ -193,7 +201,9 @@ func SimulateMsgBeginRedelegate(m auth.AccountMapper, k stake.Keeper) simulation
 			ValidatorDstAddr: destValidatorAddress,
 			SharesAmount:     sdk.NewDecFromInt(amount),
 		}
-		require.Nil(t, msg.ValidateBasic(), "expected msg to pass ValidateBasic: %s", msg.GetSignBytes())
+		if msg.ValidateBasic() != nil {
+			tb.Fatalf("expected msg to pass ValidateBasic: %s, log %s", msg.GetSignBytes(), log)
+		}
 		ctx, write := ctx.CacheContext()
 		result := stake.NewHandler(k)(ctx, msg)
 		if result.IsOK() {
@@ -207,7 +217,7 @@ func SimulateMsgBeginRedelegate(m auth.AccountMapper, k stake.Keeper) simulation
 
 // SimulateMsgCompleteRedelegate
 func SimulateMsgCompleteRedelegate(k stake.Keeper) simulation.Operation {
-	return func(t *testing.T, r *rand.Rand, app *baseapp.BaseApp, ctx sdk.Context, keys []crypto.PrivKey, log string, event func(string)) (action string, fOp []simulation.FutureOperation, err sdk.Error) {
+	return func(tb testing.TB, r *rand.Rand, app *baseapp.BaseApp, ctx sdk.Context, keys []crypto.PrivKey, log string, event func(string)) (action string, fOp []simulation.FutureOperation, err sdk.Error) {
 		validatorSrcKey := simulation.RandomKey(r, keys)
 		validatorSrcAddress := sdk.AccAddress(validatorSrcKey.PubKey().Address())
 		validatorDstKey := simulation.RandomKey(r, keys)
@@ -219,7 +229,9 @@ func SimulateMsgCompleteRedelegate(k stake.Keeper) simulation.Operation {
 			ValidatorSrcAddr: validatorSrcAddress,
 			ValidatorDstAddr: validatorDstAddress,
 		}
-		require.Nil(t, msg.ValidateBasic(), "expected msg to pass ValidateBasic: %s", msg.GetSignBytes())
+		if msg.ValidateBasic() != nil {
+			tb.Fatalf("expected msg to pass ValidateBasic: %s, log %s", msg.GetSignBytes(), log)
+		}
 		ctx, write := ctx.CacheContext()
 		result := stake.NewHandler(k)(ctx, msg)
 		if result.IsOK() {