diff --git a/nl/netlink_handler_test.go b/nl/netlink_handler_test.go
index b7bed8f..90627b0 100644
--- a/nl/netlink_handler_test.go
+++ b/nl/netlink_handler_test.go
@@ -26,8 +26,8 @@ func TestRemoveVethFromOVS(t *testing.T) {
 	assert.Equal(t, 0, len(bridges))
 
 	bridgeName := "br0"
-	dpType := "system"
-	err = o.CreateBridge(bridgeName, dpType)
+	const dpTypeSystem = "system"
+	err = o.CreateBridge(bridgeName, dpTypeSystem)
 	defer o.DeleteBridge(bridgeName)
 	assert.NoError(t, err)
 
diff --git a/openvswitch/ovs_test.go b/openvswitch/ovs_test.go
index 5a7880c..83de988 100644
--- a/openvswitch/ovs_test.go
+++ b/openvswitch/ovs_test.go
@@ -39,8 +39,8 @@ func TestBridgeOperations(t *testing.T) {
 	assert.Equal(t, 0, len(bridges))
 
 	bridgeName := "br0"
-	dpType := "system"
-	err = o.CreateBridge(bridgeName, dpType)
+	const dpTypeSystem = "system"
+	err = o.CreateBridge(bridgeName, dpTypeSystem)
 	assert.NoError(t, err)
 
 	bridges, err = o.ListBridges()
@@ -63,8 +63,8 @@ func TestBridgeOperationsFail(t *testing.T) {
 	assert.Error(t, err)
 
 	bridgeName := "br0"
-	dpType := "system"
-	err = o.CreateBridge(bridgeName, dpType)
+	const dpTypeSystem = "system"
+	err = o.CreateBridge(bridgeName, dpTypeSystem)
 	assert.Error(t, err)
 
 	_, err = o.ListBridges()
@@ -76,8 +76,8 @@ func TestBridgeOperationsFail(t *testing.T) {
 
 func TestAddDelPort(t *testing.T) {
 	bridgeName := "br0"
-	dpType := "system"
-	err := o.CreateBridge(bridgeName, dpType)
+	const dpTypeSystem = "system"
+	err := o.CreateBridge(bridgeName, dpTypeSystem)
 	defer o.DeleteBridge(bridgeName)
 
 	hName := "test0"
@@ -123,8 +123,8 @@ func TestAddDelPortFail(t *testing.T) {
 
 func TestFlowOperation(t *testing.T) {
 	bridgeName := "br0"
-	dpType := "system"
-	err := o.CreateBridge(bridgeName, dpType)
+	const dpTypeSystem = "system"
+	err := o.CreateBridge(bridgeName, dpTypeSystem)
 	defer o.DeleteBridge(bridgeName)
 	assert.NoError(t, err)
 
@@ -157,8 +157,8 @@ func TestFlowOperationsFail(t *testing.T) {
 
 func TestDumpPorts(t *testing.T) {
 	bridgeName := "br0"
-	dpType := "system"
-	err := o.CreateBridge(bridgeName, dpType)
+	const dpTypeSystem = "system"
+	err := o.CreateBridge(bridgeName, dpTypeSystem)
 	defer o.DeleteBridge(bridgeName)
 
 	hName := "test0"