public function setup()
{
$this->entity = $this->getMock('Cake\\ORM\\Entity');
$this->table = $this->getMock('Cake\\ORM\\Table');
$this->data = ['tmp_name' => 'path/to/file', 'name' => 'foo.txt'];
$this->field = 'field';
$this->settings = ['filesystem' => ['adapter' => function () {
return new VfsAdapter(new Vfs());
}]];
$this->writer = new DefaultWriter($this->table, $this->entity, $this->data, $this->field, $this->settings);
$this->vfs = new Vfs();
mkdir($this->vfs->path('/tmp'));
file_put_contents($this->vfs->path('/tmp/tempfile'), 'content');
}