Class BytesIOCopy

src/click/testing.py:117–135

Patch ``io.BytesIO`` to let the written stream be copied to another. .. versionadded:: 8.2

class BytesIOCopy(io.BytesIO):
    """Patch ``io.BytesIO`` to let the written stream be copied to another.

    .. versionadded:: 8.2
    """

    copy_to: io.BytesIO

    def __init__(self, copy_to: io.BytesIO) -> None:
        super().__init__()
        self.copy_to = copy_to

    def flush(self) -> None:
        super().flush()
        self.copy_to.flush()

    def write(self, b: ReadableBuffer) -> int:
        self.copy_to.write(b)
        return super().write(b)


class StreamMixer: