public function testWriteAppendsBody()
{
$this->response->write("First\n");
$this->assertContains('First', (string) $this->response->getBody());
$this->response->write("Second\n");
$this->assertContains('First', (string) $this->response->getBody());
$this->assertContains('Second', (string) $this->response->getBody());
}