'Test deserialize_stream with an error already set.'

def test_deserialize_pre_error_mock(self, stream_mock):

    stream_mock.status.return_value = QDataStream.ReadCorruptData
    with pytest.raises(OSError, match='The    data    stream    has    read    corrupt    data.'):
        qtutils.deserialize_stream(stream_mock, QPoint())
    assert (not stream_mock.__rshift__.called)
