def test_add(self, header, payload_length):
payload = payload_length * b"\0"
message = header + payload
assert isinstance(message, bytes)
assert len(message) == len(header) + len(payload)
assert FetcherHeader.from_bytes(message) == header
assert FetcherHeader.from_bytes(message[:len(header)]) == header
assert message[len(header):] == payload
def test_from_bytes_failure(self):
with pytest.raises(ValueError):
FetcherHeader.from_bytes(b"random bytes")
def test_from_bytes_success(self, header):
assert FetcherHeader.from_bytes(bytes(header) + 42 * b"*") == header