diff --git a/circle.yml b/circle.yml
index 006e1230..e6a05be2 100644
--- a/circle.yml
+++ b/circle.yml
@@ -11,4 +11,5 @@ database:
 test:
   override:
     # './...' is a relative pattern which means all subdirectories
-    - go test -v -race
\ No newline at end of file
+    - go test -v -race
+    - go test -v -race --dbtype=sqlite3
diff --git a/db_test.go b/db_test.go
index 94c4ea4f..43637e8c 100644
--- a/db_test.go
+++ b/db_test.go
@@ -2,7 +2,7 @@ package core
 
 import (
 	"errors"
-	"fmt"
+	"flag"
 	"os"
 	"testing"
 	"time"
@@ -12,8 +12,7 @@ import (
 )
 
 var (
-	//dbtype         string = "sqlite3"
-	dbtype         string = "mysql"
+	dbtype         = flag.String("dbtype", "mysql", "database type")
 	createTableSql string
 )
 
@@ -28,7 +27,8 @@ type User struct {
 }
 
 func init() {
-	switch dbtype {
+	flag.Parse()
+	switch *dbtype {
 	case "sqlite3":
 		createTableSql = "CREATE TABLE IF NOT EXISTS `user` (`id` INTEGER PRIMARY KEY AUTOINCREMENT NOT NULL, `name` TEXT NULL, " +
 			"`title` TEXT NULL, `age` FLOAT NULL, `alias` TEXT NULL, `nick_name` TEXT NULL, `created` datetime);"
@@ -41,7 +41,7 @@ func init() {
 }
 
 func testOpen() (*DB, error) {
-	switch dbtype {
+	switch *dbtype {
 	case "sqlite3":
 		os.Remove("./test.db")
 		return Open("sqlite3", "./test.db")
@@ -133,7 +133,7 @@ func BenchmarkStructQuery(b *testing.B) {
 				b.Error(err)
 			}
 			if user.Name != "xlw" {
-				fmt.Println(user)
+				b.Log(user)
 				b.Error(errors.New("name should be xlw"))
 			}
 		}
@@ -179,7 +179,7 @@ func BenchmarkStruct2Query(b *testing.B) {
 				b.Error(err)
 			}
 			if user.Name != "xlw" {
-				fmt.Println(user)
+				b.Log(user)
 				b.Error(errors.New("name should be xlw"))
 			}
 		}
@@ -228,9 +228,8 @@ func BenchmarkSliceInterfaceQuery(b *testing.B) {
 			if err != nil {
 				b.Error(err)
 			}
-			fmt.Println(slice)
+			b.Log(slice)
 			if *slice[1].(*string) != "xlw" {
-				fmt.Println(slice)
 				b.Error(errors.New("name should be xlw"))
 			}
 		}
@@ -332,7 +331,7 @@ func BenchmarkSliceStringQuery(b *testing.B) {
 				b.Error(err)
 			}
 			if (*slice[1]) != "xlw" {
-				fmt.Println(slice)
+				b.Log(slice)
 				b.Error(errors.New("name should be xlw"))
 			}
 		}
@@ -378,7 +377,7 @@ func BenchmarkMapInterfaceQuery(b *testing.B) {
 				b.Error(err)
 			}
 			if m["name"].(string) != "xlw" {
-				fmt.Println(m)
+				b.Log(m)
 				b.Error(errors.New("name should be xlw"))
 			}
 		}
@@ -579,7 +578,7 @@ func TestExecMap(t *testing.T) {
 		if err != nil {
 			t.Error(err)
 		}
-		fmt.Println("--", user)
+		t.Log("--", user)
 	}
 }
 
@@ -621,7 +620,7 @@ func TestExecStruct(t *testing.T) {
 		if err != nil {
 			t.Error(err)
 		}
-		fmt.Println("1--", user)
+		t.Log("1--", user)
 	}
 }
 
diff --git a/pk_test.go b/pk_test.go
index 05486086..7986ae41 100644
--- a/pk_test.go
+++ b/pk_test.go
@@ -1,7 +1,6 @@
 package core
 
 import (
-	"fmt"
 	"reflect"
 	"testing"
 )
@@ -12,14 +11,14 @@ func TestPK(t *testing.T) {
 	if err != nil {
 		t.Error(err)
 	}
-	fmt.Println(str)
+	t.Log(str)
 
 	s := &PK{}
 	err = s.FromString(str)
 	if err != nil {
 		t.Error(err)
 	}
-	fmt.Println(s)
+	t.Log(s)
 
 	if len(*p) != len(*s) {
 		t.Fatal("p", *p, "should be equal", *s)
diff --git a/scan.go b/scan.go
index 7da338d8..b7c159b2 100644
--- a/scan.go
+++ b/scan.go
@@ -44,6 +44,9 @@ func convertTime(dest *NullTime, src interface{}) error {
 		}
 		*dest = NullTime(t)
 		return nil
+	case time.Time:
+		*dest = NullTime(s)
+		return nil
 	case nil:
 	default:
 		return fmt.Errorf("unsupported driver -> Scan pair: %T -> %T", src, dest)