feat(fase1): typed savings ledger with deterministic provenance (F1)

tests/test_ledger.py

@@ -0,0 +1,101 @@
+"""Behavioral tests for the typed savings ledger (Fase 1, Step 4 — SC3 + SC8-identical).
+
+Multiple realized entries (distinct candidates) total correctly per-project and per-portfolio; each
+entry carries provenance + a ``verdict_id`` link; a malformed entry raises ``ValidationError``
+(fail-fast, contrast the tolerant verdict inbox); the same input serialized twice is byte-identical
+(SC8 determinism). Model tests: ``tests/test_portfolio.py:49`` (aggregate), ``tests/test_contracts.py``
+(fail-fast).
+"""
+
+from __future__ import annotations
+
+import pytest
+from pydantic import ValidationError
+
+from portfolio_optimiser.ledger import LedgerEntry, SavingsLedger, stamp
+
+_TS = "2026-07-06T00:00:00Z"
+
+
+def _entry(
+    project_id: str,
+    candidate_identity: str,
+    amount_ore: int,
+    *,
+    dimension: str = "energi",
+    verdict_id: str = "v1",
+) -> LedgerEntry:
+    return LedgerEntry(
+        project_id=project_id,
+        dimension=dimension,
+        candidate_identity=candidate_identity,
+        amount_ore=amount_ore,
+        verdict_id=verdict_id,
+        provenance=stamp(approver="ekspert", experiment="fase1-sim", timestamp=_TS),
+    )
+
+
+def test_totals_per_project_and_portfolio() -> None:
+    ledger = SavingsLedger()
+    assert ledger.add_realized(_entry("P1", "c-a", 1000)) is True
+    assert ledger.add_realized(_entry("P1", "c-b", 2500)) is True
+    assert ledger.add_realized(_entry("P2", "c-c", 4000)) is True
+    assert ledger.per_project_total("P1") == 3500
+    assert ledger.per_project_total("P2") == 4000
+    assert ledger.portfolio_total() == 7500
+
+
+def test_entry_carries_provenance_and_verdict_link() -> None:
+    e = _entry("P1", "c-a", 1000, verdict_id="verdict-xyz")
+    assert e.verdict_id == "verdict-xyz"
+    assert "godkjent av ekspert" in e.provenance
+    assert _TS in e.provenance  # timestamp is baked into the stamp (deterministic, no wall-clock)
+
+
+def test_malformed_entry_raises_validation_error() -> None:
+    """Fail-fast (contrast the tolerant inbox): a negative ``amount_ore`` violates ``ge=0``."""
+    with pytest.raises(ValidationError):
+        LedgerEntry(
+            project_id="P1",
+            dimension="energi",
+            candidate_identity="c-a",
+            amount_ore=-1,
+            verdict_id="v1",
+            provenance="x",
+        )
+
+
+def test_load_rejects_malformed_row(tmp_path) -> None:
+    """A malformed on-disk row raises ``ValidationError`` on load (fail-fast, never skipped)."""
+    bad = tmp_path / "ledger.json"
+    bad.write_text('[{"project_id": "P1"}]', encoding="utf-8")  # missing required fields
+    with pytest.raises(ValidationError):
+        SavingsLedger.load(str(bad))
+
+
+def test_load_missing_file_raises(tmp_path) -> None:
+    with pytest.raises(FileNotFoundError):
+        SavingsLedger.load(str(tmp_path / "does-not-exist.json"))
+
+
+def test_save_is_byte_identical_regardless_of_order(tmp_path) -> None:
+    """SC8 determinism: the same entries inserted in different order serialize byte-identically
+    (sorted keys + integer øre => the on-disk form is order-independent)."""
+    a = SavingsLedger()
+    a.add_realized(_entry("P2", "c-c", 4000))
+    a.add_realized(_entry("P1", "c-a", 1000))
+    a.add_realized(_entry("P1", "c-b", 2500))
+
+    b = SavingsLedger()
+    b.add_realized(_entry("P1", "c-b", 2500))
+    b.add_realized(_entry("P1", "c-a", 1000))
+    b.add_realized(_entry("P2", "c-c", 4000))
+
+    pa, pb = tmp_path / "a.json", tmp_path / "b.json"
+    a.save(str(pa))
+    b.save(str(pb))
+    assert pa.read_text(encoding="utf-8") == pb.read_text(encoding="utf-8")
+
+    # Round-trips: load() reconstructs an equivalent ledger with the same totals.
+    reloaded = SavingsLedger.load(str(pa))
+    assert reloaded.portfolio_total() == 7500