diff --git a/x/mock/simulation/types.go b/x/mock/simulation/operation.go
similarity index 66%
rename from x/mock/simulation/types.go
rename to x/mock/simulation/operation.go
index 2789ca6994..21b606b373 100644
--- a/x/mock/simulation/types.go
+++ b/x/mock/simulation/operation.go
@@ -8,9 +8,6 @@ import (
 	sdk "github.com/cosmos/cosmos-sdk/types"
 )
 
-// RandSetup performs the random setup the mock module needs.
-type RandSetup func(r *rand.Rand, accounts []Account)
-
 // Operation runs a state machine transition, and ensures the transition
 // happened as expected.  The operation could be running and testing a fuzzed
 // transaction, or doing the same for a message.
@@ -24,6 +21,9 @@ type Operation func(r *rand.Rand, app *baseapp.BaseApp, ctx sdk.Context,
 	accounts []Account, event func(string)) (
 	action string, futureOperations []FutureOperation, err error)
 
+// queue of operations
+type OperationQueue map[int][]Operation
+
 // FutureOperation is an operation which will be ran at the beginning of the
 // provided BlockHeight. If both a BlockHeight and BlockTime are specified, it
 // will use the BlockHeight. In the (likely) event that multiple operations
@@ -40,3 +40,31 @@ type WeightedOperation struct {
 	Weight int
 	Op     Operation
 }
+
+// WeightedOperations is the group of all weighted operations to simulate.
+type WeightedOperations []WeightedOperation
+
+func (w WeightedOperations) totalWeight() int {
+	totalOpWeight := 0
+	for i := 0; i < len(w); i++ {
+		totalOpWeight += w[i].Weight
+	}
+	return totalOpWeight
+}
+
+type selectOpFn func(r *rand.Rand) Operation
+
+func (w WeightedOperations) getSelectOpFn() selectOpFn {
+	totalOpWeight := ops.totalWeight()
+	return func(r *rand.Rand) Operation {
+		x := r.Intn(totalOpWeight)
+		for i := 0; i < len(ops); i++ {
+			if x <= ops[i].Weight {
+				return ops[i].Op
+			}
+			x -= ops[i].Weight
+		}
+		// shouldn't happen
+		return ops[0].Op
+	}
+}
diff --git a/x/mock/simulation/simulate.go b/x/mock/simulation/simulate.go
index f963e94919..849f4eeaef 100644
--- a/x/mock/simulation/simulate.go
+++ b/x/mock/simulation/simulate.go
@@ -20,6 +20,9 @@ import (
 	sdk "github.com/cosmos/cosmos-sdk/types"
 )
 
+// RandSetup performs the random setup the mock module needs.
+type RandSetup func(r *rand.Rand, accounts []Account)
+
 // Simulate tests application by sending random messages.
 func Simulate(t *testing.T, app *baseapp.BaseApp,
 	appStateFn func(r *rand.Rand, accs []Account) json.RawMessage,
@@ -27,26 +30,25 @@ func Simulate(t *testing.T, app *baseapp.BaseApp,
 	invariants []Invariant, numBlocks int, blockSize int, commit bool) error {
 
 	time := time.Now().UnixNano()
-	return SimulateFromSeed(t, app, appStateFn, time, ops, setups, invariants, numBlocks, blockSize, commit)
+	return SimulateFromSeed(t, app, appStateFn, time, ops,
+		setups, invariants, numBlocks, blockSize, commit)
 }
 
+// initialize the chain for the simulation
 func initChain(r *rand.Rand, params Params,
 	accounts []Account, setups []RandSetup, app *baseapp.BaseApp,
-	appStateFn func(r *rand.Rand, accounts []Account) json.RawMessage) (
-	validators map[string]mockValidator) {
+	appStateFn func(r *rand.Rand, accounts []Account) json.RawMessage) mockValidators {
 
-	res := app.InitChain(abci.RequestInitChain{AppStateBytes: appStateFn(r, accounts)})
-	validators = make(map[string]mockValidator)
-	for _, validator := range res.Validators {
-		str := fmt.Sprintf("%v", validator.PubKey)
-		validators[str] = mockValidator{validator, GetMemberOfInitialState(r, params.InitialLivenessWeightings)}
+	req := abci.RequestInitChain{
+		AppStateBytes: appStateFn(r, accounts),
 	}
+	res := app.InitChain(req)
+	validators = newMockValidators(res.Validators)
 
 	for i := 0; i < len(setups); i++ {
 		setups[i](r, accounts)
 	}
-
-	return
+	return validators
 }
 
 // SimulateFromSeed tests an application by running the provided
@@ -230,31 +232,16 @@ func SimulateFromSeed(tb testing.TB, app *baseapp.BaseApp,
 type blockSimFn func(r *rand.Rand, app *baseapp.BaseApp, ctx sdk.Context,
 	accounts []Account, header abci.Header, logWriter func(string)) (opCount int)
 
-// Returns a function to simulate blocks. Written like this to avoid constant parameters being passed everytime, to minimize
-// memory overhead
+// Returns a function to simulate blocks. Written like this to avoid constant
+// parameters being passed everytime, to minimize memory overhead
 func createBlockSimulator(testingMode bool, tb testing.TB, t *testing.T, params Params,
-	event func(string), invariants []Invariant, ops []WeightedOperation,
+	event func(string), invariants []Invariant, ops WeightedOperations,
 	operationQueue map[int][]Operation, timeOperationQueue []FutureOperation,
 	totalNumBlocks int, avgBlockSize int, displayLogs func()) blockSimFn {
 
 	var lastBlocksizeState = 0 // state for [4 * uniform distribution]
-	var totalOpWeight = 0
 	var blocksize int
-
-	for i := 0; i < len(ops); i++ {
-		totalOpWeight += ops[i].Weight
-	}
-	selectOp := func(r *rand.Rand) Operation {
-		x := r.Intn(totalOpWeight)
-		for i := 0; i < len(ops); i++ {
-			if x <= ops[i].Weight {
-				return ops[i].Op
-			}
-			x -= ops[i].Weight
-		}
-		// shouldn't happen
-		return ops[0].Op
-	}
+	selectOp := ops.getSelectOpFn()
 
 	return func(r *rand.Rand, app *baseapp.BaseApp, ctx sdk.Context,
 		accounts []Account, header abci.Header, logWriter func(string)) (opCount int) {
diff --git a/x/mock/simulation/validator.go b/x/mock/simulation/validator.go
index 3bbe1050cc..7a2213bdb7 100644
--- a/x/mock/simulation/validator.go
+++ b/x/mock/simulation/validator.go
@@ -16,6 +16,26 @@ type mockValidator struct {
 	livenessState int
 }
 
+type mockValidators map[string]mockValidator
+
+// get mockValidators from abci validators
+func newMockValidators(abciVals abci.ValidatorUpdate) mockValidators {
+
+	validators = make(mockValidators)
+	for _, validator := range abciVals {
+		str := fmt.Sprintf("%v", validator.PubKey)
+		liveliness := GetMemberOfInitialState(r,
+			params.InitialLivenessWeightings)
+
+		validators[str] = mockValidator{
+			val:           validator,
+			livenessState: liveliness,
+		}
+	}
+
+	return validators
+}
+
 // TODO describe usage
 func getKeys(validators map[string]mockValidator) []string {
 	keys := make([]string, len(validators))