diff --git a/lib/zerobin/db.php b/lib/zerobin/db.php
index 1248675..f920310 100644
--- a/lib/zerobin/db.php
+++ b/lib/zerobin/db.php
@@ -139,7 +139,7 @@ class zerobin_db extends zerobin_abstract
                 $tables = $statement->fetchAll(PDO::FETCH_COLUMN, 0);
 
                 // create paste table if needed
-                if (!array_key_exists(self::$_prefix . 'paste', $tables))
+                if (!in_array(self::$_prefix . 'paste', $tables))
                 {
                     self::$_db->exec(
                         'CREATE TABLE ' . self::$_prefix . 'paste ( ' .
diff --git a/tst/model.php b/tst/model.php
index aefa8f8..c5c21c1 100644
--- a/tst/model.php
+++ b/tst/model.php
@@ -146,6 +146,7 @@ class modelTest extends PHPUnit_Framework_TestCase
         $this->_model->getPaste(helper::getPasteId())->delete();
         $paste = $this->_model->getPaste();
         $paste->setData($pasteData['data']);
+        $paste->setBurnafterreading('0');
         $paste->setOpendiscussion();
         $paste->store();
 
@@ -166,4 +167,45 @@ class modelTest extends PHPUnit_Framework_TestCase
         $this->assertFalse(model_paste::isValidId('foo'), 'invalid hex values');
         $this->assertFalse(model_paste::isValidId('../bar/baz'), 'path attack');
     }
+
+    /**
+     * @expectedException Exception
+     * @expectedExceptionCode 62
+     */
+    public function testInvalidComment()
+    {
+        $paste = $this->_model->getPaste();
+        $comment = $paste->getComment(helper::getPasteId());
+    }
+
+    public function testExpiration()
+    {
+        $pasteData = helper::getPaste();
+        $this->_model->getPaste(helper::getPasteId())->delete();
+        $paste = $this->_model->getPaste(helper::getPasteId());
+        $this->assertFalse($paste->exists(), 'paste does not yet exist');
+
+        $paste = $this->_model->getPaste();
+        $paste->setData($pasteData['data']);
+        $paste->setExpiration('5min'); // = 300 seconds
+        $paste->store();
+
+        $paste = $paste->get();
+        $this->assertEquals(300, $paste->meta->remaining_time, 'remaining time is set correctly');
+    }
+
+    /**
+     * @expectedException Exception
+     * @expectedExceptionCode 64
+     */
+    public function testCommentDeletion()
+    {
+        $pasteData = helper::getPaste();
+        $this->_model->getPaste(helper::getPasteId())->delete();
+
+        $paste = $this->_model->getPaste();
+        $paste->setData($pasteData['data']);
+        $paste->store();
+        $paste->getComment(helper::getPasteId())->delete();
+    }
 }
\ No newline at end of file
diff --git a/tst/zerobin/db.php b/tst/zerobin/db.php
index 0c6b016..3697b50 100644
--- a/tst/zerobin/db.php
+++ b/tst/zerobin/db.php
@@ -3,17 +3,17 @@ class zerobin_dbTest extends PHPUnit_Framework_TestCase
 {
     private $_model;
 
+    private $_options = array(
+        'dsn' => 'sqlite::memory:',
+        'usr' => null,
+        'pwd' => null,
+        'opt' => array(PDO::ATTR_ERRMODE => PDO::ERRMODE_EXCEPTION),
+    );
+
     public function setUp()
     {
         /* Setup Routine */
-        $this->_model = zerobin_db::getInstance(
-            array(
-                'dsn' => 'sqlite::memory:',
-                'usr' => null,
-                'pwd' => null,
-                'opt' => array(PDO::ATTR_ERRMODE => PDO::ERRMODE_EXCEPTION),
-            )
-        );
+        $this->_model = zerobin_db::getInstance($this->_options);
     }
 
     public function testDatabaseBasedDataStoreWorks()
@@ -51,6 +51,7 @@ class zerobin_dbTest extends PHPUnit_Framework_TestCase
     {
         $this->_model->delete(helper::getPasteId());
         $original = $paste = helper::getPasteWithAttachment(array('expire_date' => 1344803344));
+        $paste['meta']['burnafterreading'] = $original['meta']['burnafterreading'] = true;
         $paste['meta']['attachment'] = $paste['attachment'];
         $paste['meta']['attachmentname'] = $paste['attachmentname'];
         unset($paste['attachment'], $paste['attachmentname']);
@@ -137,4 +138,29 @@ class zerobin_dbTest extends PHPUnit_Framework_TestCase
             'dsn' => 'foo:', 'usr' => null, 'pwd' => null, 'opt' => null
         ));
     }
+
+    public function testTableUpgrade()
+    {
+        $path = PATH . 'data/db-test.sq3';
+        @unlink($path);
+        $this->_options['dsn'] = 'sqlite:' . $path;
+        $this->_options['tbl'] = 'foo_';
+        $db = new PDO(
+            $this->_options['dsn'],
+            $this->_options['usr'],
+            $this->_options['pwd'],
+            $this->_options['opt']
+        );
+        $db->exec(
+            'CREATE TABLE foo_paste ( ' .
+            'dataid CHAR(16), ' .
+            'data TEXT, ' .
+            'postdate INT, ' .
+            'expiredate INT, ' .
+            'opendiscussion INT, ' .
+            'burnafterreading INT );'
+        );
+        zerobin_db::getInstance($this->_options);
+        @unlink($path);
+    }
 }