Fix PDO statement wrapper to work with MySQL correctly

Author: tanakahisateru

src/Pinoco/PDOStatementWrapper.php

@@ -72,7 +72,10 @@ public function execute($args=Pinoco_OptionalParam::UNSPECIFIED)
     {
         $args = func_get_args();
         $args = Pinoco_OptionalParam::trim($args);
-        if (count($args) == 1) {
+        if (count($args) == 0) {
+            $args = null;
+        }
+        elseif (count($args) == 1) {
             $args = $args[0];
             if ($args instanceof Pinoco_ArrayConvertible) {
                 $args = $args->toArray();

test/unit/PDOWrapperTest.php

@@ -65,6 +65,15 @@ public function testPrepareQuery()
         $this->assertEquals('aaa', $rs[0]->value);
         $this->assertEquals($b_id, $rs[1]->id);
         $this->assertEquals('bbb', $rs[1]->value);
+
+        $s = $this->db->prepare("insert into foo (value) values(:d);");
+        $s->bindValue(':d', 'ddd');
+        $s->execute();
+        $d_id = $this->db->lastInsertId();
+        $r = $this->db->prepare(
+            "select * from foo where id=:id;"
+        )->query($d_id)->fetchOne();
+        $this->assertEquals($d_id, $r->get('id'));
     }
 
     public function testStatement()