"""Message is the boundary every stored text passes through."""

from navi.llm.base import Message


class TestNulBytes:
    """PostgreSQL text cannot hold a NUL byte, and one arriving in a tool result
    made the whole session_messages INSERT fail with CharacterNotInRepertoireError
    — the turn died and the user lost it (three times on prod, 2026-10-07). The
    strip lives on Message so it covers every writer downstream of it.
    """

    def test_content_loses_nul_bytes(self):
        assert Message(role="tool", content="bi\x00nary").content == "binary"

    def test_thinking_loses_nul_bytes_too(self):
        assert Message(role="assistant", thinking="th\x00ink").thinking == "think"

    def test_clean_text_is_untouched(self):
        text = "привет, мир — 100% ok"
        assert Message(role="user", content=text).content == text

    def test_absent_content_stays_none(self):
        assert Message(role="assistant").content is None