def test_sequence(self):
sequence_0 = Sequence()
self.assertEqual(sequence_0, MAX_SEQUENCE)
self.assertTrue(sequence_0.is_max())
self.assertFalse(sequence_0.is_relative())
self.assertIsNone(sequence_0.relative_blocks())
self.assertIsNone(sequence_0.relative_time())
self.assertEqual(Sequence.parse(BytesIO(sequence_0.serialize())),
sequence_0)
time_amount = 512 * 1000
sequence_1 = Sequence.from_relative_time(time_amount)
self.assertFalse(sequence_1.is_comparable(sequence_0))
self.assertIsNone(sequence_1.relative_blocks())
self.assertEqual(sequence_1.relative_time(), time_amount)
self.assertEqual(Sequence.parse(BytesIO(sequence_1.serialize())),
sequence_1)
blocks_amount = 144
sequence_2 = Sequence.from_relative_blocks(blocks_amount)
self.assertIsNone(sequence_2.relative_time())
self.assertEqual(sequence_2.relative_blocks(), blocks_amount)
self.assertFalse(sequence_1.is_comparable(sequence_2))
sequence_3 = Sequence.from_relative_time(512 * 100)
self.assertTrue(sequence_3 < sequence_1)
with self.assertRaises(ValueError):
sequence_2 < sequence_0
with self.assertRaises(ValueError):
sequence_2 < sequence_1
with self.assertRaises(ValueError):
Sequence(-1)
with self.assertRaises(ValueError):
Sequence(1 << 32)
def parse(cls, s):
"""Takes a byte stream and parses the tx_input at the start
return a TxIn object
"""
# s.read(n) will return n bytes
# prev_tx is 32 bytes, little endian
prev_tx = s.read(32)[::-1]
# prev_index is 4 bytes, little endian, interpret as int
prev_index = little_endian_to_int(s.read(4))
# script_sig is a variable field (length followed by the data)
# you can use Script.parse to get the actual script
script_sig = Script.parse(s)
# sequence is 4 bytes, little-endian, interpret as int
sequence = Sequence.parse(s)
# return an instance of the class (cls(...))
return cls(prev_tx, prev_index, script_sig, sequence)