diff --git a/action/protocol/poll/protocol.go b/action/protocol/poll/protocol.go
index fe69b3e716..346daa7491 100644
--- a/action/protocol/poll/protocol.go
+++ b/action/protocol/poll/protocol.go
@@ -26,9 +26,8 @@ import (
 )
 
 const (
-	_protocolID = "poll"
-	// RollDPoSScheme means randomized delegated proof of stake
-	RollDPoSScheme = "ROLLDPOS"
+	_protocolID     = "poll"
+	_rollDPoSScheme = "ROLLDPOS"
 )
 
 const (
@@ -139,7 +138,7 @@ func NewProtocol(
 	productivity Productivity,
 	getBlockHash evm.GetBlockHash,
 ) (Protocol, error) {
-	if scheme != RollDPoSScheme {
+	if scheme != _rollDPoSScheme {
 		return nil, nil
 	}
 
diff --git a/action/protocol/poll/protocol_test.go b/action/protocol/poll/protocol_test.go
index c30fcfabab..bbbc799f8b 100644
--- a/action/protocol/poll/protocol_test.go
+++ b/action/protocol/poll/protocol_test.go
@@ -29,7 +29,7 @@ func TestNewProtocol(t *testing.T) {
 	g := genesis.Default
 	g.ScoreThreshold = "1200000"
 	p, err := NewProtocol(
-		RollDPoSScheme,
+		_rollDPoSScheme,
 		blockchain.DefaultConfig,
 		g,
 		nil,
diff --git a/action/protocol/rewarding/reward_test.go b/action/protocol/rewarding/reward_test.go
index 6cad54d52a..71f554e7df 100644
--- a/action/protocol/rewarding/reward_test.go
+++ b/action/protocol/rewarding/reward_test.go
@@ -366,7 +366,6 @@ func TestProtocol_NoRewardAddr(t *testing.T) {
 		},
 	}
 	g := genesis.Default
-	bcf := blockchain.DefaultConfig
 	committee := mock_committee.NewMockCommittee(ctrl)
 	slasher, err := poll.NewSlasher(
 		func(uint64, uint64) (map[string]uint64, error) {
@@ -394,7 +393,7 @@ func TestProtocol_NoRewardAddr(t *testing.T) {
 		committee,
 		uint64(123456),
 		func(uint64) (time.Time, error) { return time.Now(), nil },
-		bcf.PollInitialCandidatesInterval,
+		blockchain.DefaultConfig.PollInitialCandidatesInterval,
 		slasher,
 	)
 	require.NoError(t, err)
diff --git a/actpool/actpool_test.go b/actpool/actpool_test.go
index 4026a0170f..2a4bea4993 100644
--- a/actpool/actpool_test.go
+++ b/actpool/actpool_test.go
@@ -1195,3 +1195,9 @@ func lenPendingActionMap(acts map[string][]action.SealedEnvelope) int {
 	}
 	return l
 }
+
+func TestValidateMinGasPrice(t *testing.T) {
+	ap := Config{MinGasPriceStr: DefaultConfig.MinGasPriceStr}
+	mgp := ap.MinGasPrice()
+	require.IsType(t, &big.Int{}, mgp)
+}
diff --git a/config/config_test.go b/config/config_test.go
index db4c5b9d41..a98020861e 100644
--- a/config/config_test.go
+++ b/config/config_test.go
@@ -8,7 +8,6 @@ package config
 
 import (
 	"fmt"
-	"math/big"
 	"os"
 	"path/filepath"
 	"strings"
@@ -18,7 +17,6 @@ import (
 	"github.com/pkg/errors"
 	"github.com/stretchr/testify/require"
 
-	"github.com/iotexproject/iotex-core/actpool"
 	"github.com/iotexproject/iotex-core/blockchain/genesis"
 )
 
@@ -312,13 +310,6 @@ func TestValidateActPool(t *testing.T) {
 	)
 }
 
-func TestValidateMinGasPrice(t *testing.T) {
-	ap := actpool.Config{MinGasPriceStr: Default.ActPool.MinGasPriceStr}
-	mgp := ap.MinGasPrice()
-	fmt.Printf("%T,%v", mgp, mgp)
-	require.IsType(t, &big.Int{}, mgp)
-}
-
 func TestValidateForkHeights(t *testing.T) {
 	r := require.New(t)