Add DB method

gorm.go

@@ -3,6 +3,7 @@ package gorm
 import (
 	"context"
 	"database/sql"
+	"errors"
 	"fmt"
 	"sync"
 	"time"
@@ -220,6 +221,21 @@ func (db *DB) AddError(err error) error {
 	return db.Error
 }
 
+// DB returns `*sql.DB`
+func (db *DB) DB() (*sql.DB, error) {
+	connPool := db.ConnPool
+
+	if stmtDB, ok := connPool.(*PreparedStmtDB); ok {
+		connPool = stmtDB.ConnPool
+	}
+
+	if sqldb, ok := connPool.(*sql.DB); ok {
+		return sqldb, nil
+	}
+
+	return nil, errors.New("invalid db")
+}
+
 func (db *DB) getInstance() *DB {
 	if db.clone > 0 {
 		tx := &DB{Config: db.Config}

tests/tests_test.go

@@ -24,6 +24,15 @@ func init() {
 		log.Printf("failed to connect database, got error %v\n", err)
 		os.Exit(1)
 	} else {
+		sqlDB, err := DB.DB()
+		if err == nil {
+			err = sqlDB.Ping()
+		}
+
+		if err != nil {
+			log.Printf("failed to connect database, got error %v\n", err)
+		}
+
 		RunMigrations()
 	}
 }