def test_load_header():
stream = io.StringIO()
a = TextStream(stream)
a.write_header("hoge")
stream.seek(0)
assert a.load_header() == "hoge"
def test_write_header():
stream = io.StringIO()
a = TextStream(stream)
a.write_header("hoge")
stream.seek(0)
assert stream.readline() == "hoge\n"