"""Tests for OP_RETURN primitives."""
import pytest
from mcp_bitcoin_cli.primitives import (
encode_op_return_script,
decode_op_return_script,
OP_RETURN,
OP_PUSHDATA1,
OP_PUSHDATA2,
OP_PUSHDATA4,
)
from mcp_bitcoin_cli.envelope import EnvelopeType, encode_envelope
class TestOpReturnEncoding:
"""Test OP_RETURN script encoding."""
def test_encode_small_data(self):
"""Encode small data (< 76 bytes) directly."""
data = b"hello"
script = encode_op_return_script(data)
assert script[0] == OP_RETURN
assert script[1] == len(data) # Direct push
assert script[2:] == data
def test_encode_medium_data(self):
"""Encode medium data (76-255 bytes) with PUSHDATA1."""
data = b"x" * 100
script = encode_op_return_script(data)
assert script[0] == OP_RETURN
assert script[1] == OP_PUSHDATA1
assert script[2] == len(data)
assert script[3:] == data
def test_encode_large_data(self):
"""Encode large data (256+ bytes) with PUSHDATA2."""
data = b"x" * 300
script = encode_op_return_script(data)
assert script[0] == OP_RETURN
assert script[1] == OP_PUSHDATA2
# Little-endian length
assert int.from_bytes(script[2:4], 'little') == len(data)
assert script[4:] == data
def test_encode_with_envelope(self):
"""Encode data wrapped in envelope."""
data = b"test"
envelope = encode_envelope(data, EnvelopeType.TEXT)
script = encode_op_return_script(envelope)
# Script contains envelope with magic bytes
assert b"BTCD" in script
class TestOpReturnDecoding:
"""Test OP_RETURN script decoding."""
def test_decode_small_data(self):
"""Decode small OP_RETURN."""
data = b"hello"
script = encode_op_return_script(data)
decoded = decode_op_return_script(script)
assert decoded == data
def test_decode_medium_data(self):
"""Decode medium OP_RETURN with PUSHDATA1."""
data = b"x" * 100
script = encode_op_return_script(data)
decoded = decode_op_return_script(script)
assert decoded == data
def test_decode_large_data(self):
"""Decode large OP_RETURN with PUSHDATA2."""
data = b"x" * 300
script = encode_op_return_script(data)
decoded = decode_op_return_script(script)
assert decoded == data
def test_decode_invalid_opcode(self):
"""Reject non-OP_RETURN script."""
script = bytes([0x76, 0x05]) + b"hello" # OP_DUP instead
with pytest.raises(ValueError, match="not an OP_RETURN"):
decode_op_return_script(script)
def test_roundtrip_max_size(self):
"""Roundtrip near-max OP_RETURN (100KB)."""
data = b"x" * 99000
script = encode_op_return_script(data)
decoded = decode_op_return_script(script)
assert decoded == data
class TestMalformedScripts:
"""Test handling of malformed OP_RETURN scripts."""
def test_truncated_pushdata1_no_length(self):
"""PUSHDATA1 with no length byte should raise ValueError."""
script = bytes([OP_RETURN, OP_PUSHDATA1]) # Missing length byte
with pytest.raises(ValueError, match="Truncated PUSHDATA1"):
decode_op_return_script(script)
def test_truncated_pushdata2_partial_length(self):
"""PUSHDATA2 with only 1 length byte should raise ValueError."""
script = bytes([OP_RETURN, OP_PUSHDATA2, 0x00]) # Only 1 of 2 length bytes
with pytest.raises(ValueError, match="Truncated PUSHDATA2"):
decode_op_return_script(script)
def test_truncated_pushdata2_no_length(self):
"""PUSHDATA2 with no length bytes should raise ValueError."""
script = bytes([OP_RETURN, OP_PUSHDATA2])
with pytest.raises(ValueError, match="Truncated PUSHDATA2"):
decode_op_return_script(script)
def test_truncated_pushdata4_partial_length(self):
"""PUSHDATA4 with only 2 length bytes should raise ValueError."""
script = bytes([OP_RETURN, OP_PUSHDATA4, 0x00, 0x00]) # Only 2 of 4 length bytes
with pytest.raises(ValueError, match="Truncated PUSHDATA4"):
decode_op_return_script(script)
def test_truncated_pushdata4_no_length(self):
"""PUSHDATA4 with no length bytes should raise ValueError."""
script = bytes([OP_RETURN, OP_PUSHDATA4])
with pytest.raises(ValueError, match="Truncated PUSHDATA4"):
decode_op_return_script(script)
def test_truncated_data_direct_push(self):
"""Direct push with declared length > actual data should raise ValueError."""
# Declares 10 bytes but only has 3
script = bytes([OP_RETURN, 10]) + b"abc"
with pytest.raises(ValueError, match="Script truncated.*expected 10 bytes.*got 3"):
decode_op_return_script(script)
def test_truncated_data_pushdata1(self):
"""PUSHDATA1 with declared length > actual data should raise ValueError."""
# Declares 100 bytes but only has 5
script = bytes([OP_RETURN, OP_PUSHDATA1, 100]) + b"hello"
with pytest.raises(ValueError, match="Script truncated.*expected 100 bytes.*got 5"):
decode_op_return_script(script)
def test_truncated_data_pushdata2(self):
"""PUSHDATA2 with declared length > actual data should raise ValueError."""
# Declares 1000 bytes (little-endian) but only has 10
length_bytes = (1000).to_bytes(2, 'little')
script = bytes([OP_RETURN, OP_PUSHDATA2]) + length_bytes + b"0123456789"
with pytest.raises(ValueError, match="Script truncated.*expected 1000 bytes.*got 10"):
decode_op_return_script(script)
def test_script_too_short(self):
"""Script with less than 2 bytes should raise ValueError."""
with pytest.raises(ValueError, match="Script too short"):
decode_op_return_script(bytes([OP_RETURN]))
with pytest.raises(ValueError, match="Script too short"):
decode_op_return_script(bytes([]))
