Accept empty strings as empty sessions

tests/TestCase/Network/Session/DatabaseSessionTest.php

@@ -130,7 +130,7 @@ class DatabaseSessionTest extends TestCase
         $this->assertEquals($expected, $result);
 
         $result = $this->storage->read('made up value');
-        $this->assertFalse($result);
+        $this->assertEmpty($result);
     }
 
     /**
@@ -143,7 +143,7 @@ class DatabaseSessionTest extends TestCase
         $this->storage->write('foo', 'Some value');
 
         $this->assertTrue($this->storage->destroy('foo'), 'Destroy failed');
-        $this->assertFalse($this->storage->read('foo'), 'Value still present.');
+        $this->assertEmpty($this->storage->read('foo'), 'Value still present.');
     }
 
     /**
@@ -161,7 +161,7 @@ class DatabaseSessionTest extends TestCase
 
         sleep(1);
         $storage->gc(0);
-        $this->assertFalse($storage->read('foo'));
+        $this->assertEmpty($storage->read('foo'));
     }
 
     /**