stream_write() публичный Метод

This method is called in response to fwrite(). If there is not enough room in the underlying stream, store as much as possible. Note: Remember to update the current position of the stream by number of bytes that were successfully written.
public stream_write ( string $data ) : integer
$data string Should be stored into the underlying stream.
Результат integer Should return the number of bytes that were successfully stored, or 0 if none could be stored.
 /**
  * @test
  */
 public function stream_writeTest()
 {
     $data = 'foo bar';
     $this->mockStreamWrapper->expects($this->once())->method('write')->with($data)->will($this->returnValue(true));
     $this->assertTrue($this->streamWrapperAdapter->stream_write($data));
 }