public function write()
 {
     $s = new \io\streams\MemoryOutputStream();
     $this->image->saveTo(new JpegStreamWriter($s));
     $this->assertNotEmpty($s->getBytes());
 }
 public function destructor_emits_timing()
 {
     $o = $this->observerWithSelect();
     $stream = new \io\streams\MemoryOutputStream();
     $lc = (new LogCategory('profiling'))->withAppender(new StreamAppender($stream));
     $o->setTrace($lc);
     $o = null;
     $this->assertTrue(0 < strlen($stream->getBytes()));
 }