feat(parsers+api+ui): expose CARC-labeled CAS adjustments (SP3 P2)

backend/tests/test_cas_codes.py

@@ -0,0 +1,139 @@
+"""Tests for :mod:`cyclone.parsers.cas_codes`.
+
+Covers the public API surface:
+
+- ``LAST_UPDATED`` module constant (parses as YYYY-MM-DD).
+- :func:`reason_label` — known codes return their label, unknown codes
+  fall back to ``"Unknown ({group}-{reason})"``.
+- :func:`all_known_codes` — at least 100 entries, sorted, no duplicate
+  ``(group, reason)`` pairs.
+
+The dict is a snapshot of CARC (Claim Adjustment Reason Codes); tests
+are deliberately decoupled from the exact labels (they change as
+payers revise codes) but pin down the API contract.
+"""
+
+from __future__ import annotations
+
+from datetime import date
+
+import pytest
+
+from cyclone.parsers import cas_codes
+
+
+# --------------------------------------------------------------------------- #
+# LAST_UPDATED
+# --------------------------------------------------------------------------- #
+
+
+def test_last_updated_constant() -> None:
+    """``LAST_UPDATED`` is a string that parses as YYYY-MM-DD."""
+    assert isinstance(cas_codes.LAST_UPDATED, str)
+    parsed = date.fromisoformat(cas_codes.LAST_UPDATED)
+    assert parsed.isoformat() == cas_codes.LAST_UPDATED
+
+
+# --------------------------------------------------------------------------- #
+# reason_label — known codes
+# --------------------------------------------------------------------------- #
+
+
+def test_reason_label_known_co_45() -> None:
+    """CO-45 ("Charge exceeds fee schedule…") is the most-common CARC."""
+    label = cas_codes.reason_label("CO", "45")
+    assert isinstance(label, str)
+    assert label.strip()  # non-empty
+    # We don't pin the exact text (carriers revise wording); the contract
+    # is "non-empty and not the unknown-fallback".
+    assert "Unknown" not in label
+
+
+def test_reason_label_known_pr_1() -> None:
+    """PR-1 ("Deductible amount") is the bread-and-butter PR code."""
+    label = cas_codes.reason_label("PR", "1")
+    assert isinstance(label, str)
+    assert label.strip()
+    assert "Unknown" not in label
+
+
+def test_reason_label_returns_specific_label_for_co_97() -> None:
+    """CO-97 is the bundled-payment / included-in-payment code; pins
+    that distinct codes map to distinct labels (not all the same
+    fallback string)."""
+    co45 = cas_codes.reason_label("CO", "45")
+    co97 = cas_codes.reason_label("CO", "97")
+    # Both are non-fallback but should not be identical text.
+    assert co45 != co97
+
+
+# --------------------------------------------------------------------------- #
+# reason_label — unknown fallback
+# --------------------------------------------------------------------------- #
+
+
+def test_reason_label_unknown_returns_fallback() -> None:
+    """Unknown (group, reason) pairs return ``"Unknown ({group}-{reason})"``."""
+    assert cas_codes.reason_label("XX", "999") == "Unknown (XX-999)"
+    # Even a known group with an unknown reason falls back.
+    assert cas_codes.reason_label("CO", "9999") == "Unknown (CO-9999)"
+
+
+# --------------------------------------------------------------------------- #
+# all_known_codes — shape + invariants
+# --------------------------------------------------------------------------- #
+
+
+def test_all_known_codes_count_ge_100() -> None:
+    """We need a useful snapshot — at least 100 codes."""
+    entries = cas_codes.all_known_codes()
+    assert len(entries) >= 100
+
+
+def test_all_known_codes_sorted_unique() -> None:
+    """Each entry is ``(group, reason, label)``; pairs are unique; result sorted."""
+    entries = cas_codes.all_known_codes()
+    # Shape: every entry is a 3-tuple of strings.
+    for entry in entries:
+        assert len(entry) == 3
+        group, reason, label = entry
+        assert isinstance(group, str) and group
+        assert isinstance(reason, str) and reason
+        assert isinstance(label, str) and label
+
+    # Unique (group, reason) pairs.
+    pairs = [(g, r) for g, r, _ in entries]
+    assert len(pairs) == len(set(pairs))
+
+    # Sorted by (group, reason) lexicographically.
+    assert entries == sorted(entries)
+
+
+def test_all_known_codes_includes_required_minimum_set() -> None:
+    """Pin the spec's required codes so a future dict swap that drops them
+    is caught here, not in production."""
+    entries = cas_codes.all_known_codes()
+    keys = {(g, r) for g, r, _ in entries}
+    required = {
+        ("CO", "45"), ("CO", "97"), ("CO", "16"), ("CO", "29"),
+        ("CO", "50"), ("CO", "109"), ("CO", "119"), ("CO", "197"),
+        ("CO", "204"), ("CO", "B7"), ("CO", "251"),
+        ("PR", "1"), ("PR", "2"), ("PR", "3"), ("PR", "204"),
+        ("OA", "23"), ("OA", "97"),
+        ("PI", "16"), ("PI", "21"), ("PI", "22"), ("PI", "25"),
+        ("CR", "1"), ("CR", "2"), ("CR", "3"), ("CR", "4"),
+    }
+    missing = required - keys
+    assert not missing, f"missing required CARC codes: {sorted(missing)}"
+
+
+# --------------------------------------------------------------------------- #
+# reason_label — spot-check that every dict entry round-trips correctly
+# --------------------------------------------------------------------------- #
+
+
+@pytest.mark.parametrize("entry", list(cas_codes._CARC_LABELS.items()))
+def test_reason_label_matches_dict_for_every_entry(entry) -> None:
+    """Every entry in the dict returns its own label via ``reason_label``."""
+    (group, reason), expected = entry
+    assert cas_codes.reason_label(group, reason) == expected