from __future__ import annotations

from barcode.codex import Code128

def test_build_is_stable_across_repeated_calls() -> None:

"""Calling build() repeatedly on the same instance must be deterministic.

Regression test for #143: ``_build`` mutated ``_charset`` and

``_digit_buffer`` without resetting them, so a second call started from

stale state and produced a different bit string.

"""

code = Code128("12A")

first = code.build()

assert code.build() == first

assert code.build() == first

def test_encoded_is_stable_across_repeated_calls() -> None:

"""The ``encoded`` property must also be deterministic across calls."""

code = Code128("12A")

first = code.encoded

assert code.encoded == first

assert code.encoded == first

def test_reused_instance_matches_fresh_instance() -> None:

"""A reused instance must encode identically to a freshly built one."""

reused = Code128("123ABC456")

reused.build() # dirties the internal charset/buffer state

assert reused.build() == Code128("123ABC456").build()