使用 getvalue 方法而非读取：

with fs.new_file(filename="test.png") as fp:
    fp.write(fake_file.getvalue())

或者，您可以使用 如果你第一次=https://docs.python.org/2/library/stdtypes.html#file.seek =nofollow，请阅读 > seek（0） 从StringIO的开头读取。

Alternatively, you could use read if you first seek(0) to read from the beginning of the StringIO.

with fs.new_file(filename="test.png") as fp:
    fake_file.seek(0)
    fp.write(fake_file.read())