fixed failure on sqlite version check

framework/db/sqlite/QueryBuilder.php

@@ -66,6 +66,7 @@ class QueryBuilder extends \yii\db\QueryBuilder
     {
         // SQLite supports batch insert natively since 3.7.11
         // http://www.sqlite.org/releaselog/3_7_11.html
+        $this->db->open(); // ensure pdo is not null
         if (version_compare($this->db->pdo->getAttribute(\PDO::ATTR_SERVER_VERSION), '3.7.11', '>=')) {
             return parent::batchInsert($table, $columns, $rows);
         }

tests/unit/framework/db/sqlite/SqliteQueryBuilderTest.php

@@ -84,7 +84,8 @@ class SqliteQueryBuilderTest extends QueryBuilderTest
 
     public function testBatchInsert()
     {
-        if (version_compare(\SQLite3::version()['versionString'], '3.7.11', '>=')) {
+        $db = $this->getConnection();
+        if (version_compare($db->pdo->getAttribute(\PDO::ATTR_SERVER_VERSION), '3.7.11', '>=')) {
             $this->markTestSkipped('This test is only relevant for SQLite < 3.7.11');
         }
         $sql = $this->getQueryBuilder()->batchInsert('{{customer}} t', ['t.id', 't.name'], [[1, 'a'], [2, 'b']]);