python类io()的实例源码

def test_bytes_io():
    f = py.io.BytesIO()
    f.write(tobytes("hello"))
    pytest.raises(TypeError, "f.write(totext('hello'))")
    s = f.getvalue()
    assert s == tobytes("hello")

def test_dupfile_on_bytesio():
    io = py.io.BytesIO()
    f = capture.safe_text_dupfile(io, "wb")
    f.write("hello")
    assert io.getvalue() == b"hello"

def test_dupfile_on_textio():
    io = py.io.TextIO()
    f = capture.safe_text_dupfile(io, "wb")
    f.write("hello")
    assert io.getvalue() == "hello"