"""The CID-share instrument: order 20260904T172353Z-6290714297-from-.claude.

Measures how much of a document's extracted text is undecoded `(cid:N)` glyph
codes -- the failure mode `docs/2026-09-04-k3-arm-c.md` found on Bilag 9.1
(95.1 %, 98 alphabetic words of four or more letters survive). This instrument
answers whether that document is alone or whether the corpus has more of them.

The negative control matters here as much as the positive one: an instrument
that reports a nonzero CID share on text that has none would inflate every
number it ever produces, the same reason `test_fidelity.py` pins its own
negative control.
"""

from __future__ import annotations

import sys
from pathlib import Path

sys.path.insert(0, str(Path(__file__).resolve().parents[1] / "tools"))

import okf_cid_measure  # noqa: E402


def test_known_cid_fraction() -> None:
    text = "abcd efgh " + "(cid:12)" * 2
    result = okf_cid_measure.measure(text)
    assert result.total_chars == len(text) == 26
    assert result.cid_chars == len("(cid:12)") * 2 == 16
    assert result.word_count == 2  # "abcd", "efgh" -- "cid" itself is 3 letters
    assert abs(result.pct - (16 / 26 * 100)) < 1e-9


def test_no_cid_is_zero_with_nonzero_total() -> None:
    result = okf_cid_measure.measure("plain readable text with no cid codes at all")
    assert result.total_chars > 0
    assert result.cid_chars == 0
    assert result.pct == 0.0


def test_all_cid_is_full_share_and_zero_words() -> None:
    result = okf_cid_measure.measure("(cid:1)(cid:2)(cid:3)")
    assert result.pct == 100.0
    assert result.word_count == 0


def test_empty_text_reports_zero_percent_not_a_crash() -> None:
    result = okf_cid_measure.measure("")
    assert result.total_chars == 0
    assert result.cid_chars == 0
    assert result.pct == 0.0