Initial extraction from monorepo

tests/test_scenarios.py

@@ -0,0 +1,113 @@
+"""Cartesian scenario builder + strategy/regime factory."""
+from decimal import Decimal
+
+import pytest
+
+from fire_planner.scenarios import (
+    DEFAULT_GLIDES,
+    DEFAULT_JURISDICTIONS,
+    DEFAULT_LEAVE_YEARS,
+    DEFAULT_STRATEGIES,
+    ScenarioSpec,
+    build_regime_schedule,
+    build_strategy,
+    cartesian_scenarios,
+)
+from fire_planner.strategies.guyton_klinger import GuytonKlingerStrategy
+from fire_planner.strategies.trinity import TrinityStrategy
+from fire_planner.strategies.vpw import VpwStrategy, VpwWithFloorStrategy
+from fire_planner.tax.bulgaria import BulgariaTaxRegime
+from fire_planner.tax.cyprus import CyprusTaxRegime
+from fire_planner.tax.uae import UaeTaxRegime
+from fire_planner.tax.uk import UkTaxRegime
+
+
+def test_default_cartesian_count_is_120() -> None:
+    specs = cartesian_scenarios(spending_gbp=Decimal("100000"), nw_seed_gbp=Decimal("1000000"))
+    expected = (len(DEFAULT_JURISDICTIONS) * len(DEFAULT_STRATEGIES) * len(DEFAULT_LEAVE_YEARS) *
+                len(DEFAULT_GLIDES))
+    assert expected == 120
+    assert len(specs) == 120
+
+
+def test_external_id_format() -> None:
+    spec = ScenarioSpec(
+        jurisdiction="cyprus",
+        strategy="vpw",
+        leave_uk_year=3,
+        glide_path="rising",
+        spending_gbp=Decimal("100000"),
+        nw_seed_gbp=Decimal("1000000"),
+    )
+    assert spec.external_id == "cyprus-vpw-leave-y3-glide-rising"
+
+
+def test_cartesian_unique_external_ids() -> None:
+    specs = cartesian_scenarios(spending_gbp=Decimal("100000"), nw_seed_gbp=Decimal("1000000"))
+    ids = [s.external_id for s in specs]
+    assert len(ids) == len(set(ids))
+
+
+def test_build_strategy_dispatch() -> None:
+    assert isinstance(build_strategy("trinity"), TrinityStrategy)
+    assert isinstance(build_strategy("guyton_klinger"), GuytonKlingerStrategy)
+    assert isinstance(build_strategy("vpw"), VpwStrategy)
+
+
+def test_build_strategy_vpw_floor_requires_floor() -> None:
+    s = build_strategy("vpw_floor", floor=40_000.0)
+    assert isinstance(s, VpwWithFloorStrategy)
+    assert s.floor == 40_000.0
+
+
+def test_build_strategy_vpw_floor_missing_floor_raises() -> None:
+    with pytest.raises(ValueError):
+        build_strategy("vpw_floor")
+
+
+def test_build_strategy_unknown_raises() -> None:
+    with pytest.raises(KeyError):
+        build_strategy("walmart")
+
+
+def test_build_regime_schedule_uae() -> None:
+    fn = build_regime_schedule("uae", leave_uk_year=2)
+    assert isinstance(fn(0), UkTaxRegime)
+    assert isinstance(fn(1), UkTaxRegime)
+    assert isinstance(fn(2), UaeTaxRegime)
+    assert isinstance(fn(50), UaeTaxRegime)
+
+
+def test_build_regime_schedule_uk_constant() -> None:
+    fn = build_regime_schedule("uk", leave_uk_year=3)
+    # All years should resolve to UK
+    assert isinstance(fn(0), UkTaxRegime)
+    assert isinstance(fn(50), UkTaxRegime)
+
+
+def test_build_regime_schedule_cyprus_switches_at_leave_year() -> None:
+    fn = build_regime_schedule("cyprus", leave_uk_year=3)
+    assert isinstance(fn(0), UkTaxRegime)
+    assert isinstance(fn(2), UkTaxRegime)
+    assert isinstance(fn(3), CyprusTaxRegime)
+    assert isinstance(fn(50), CyprusTaxRegime)
+
+
+def test_build_regime_schedule_bulgaria() -> None:
+    fn = build_regime_schedule("bulgaria", leave_uk_year=1)
+    assert isinstance(fn(0), UkTaxRegime)
+    assert isinstance(fn(1), BulgariaTaxRegime)
+
+
+def test_build_regime_schedule_unknown_raises() -> None:
+    with pytest.raises(KeyError):
+        build_regime_schedule("madeupistan", leave_uk_year=3)
+
+
+def test_cartesian_unknown_glide_raises() -> None:
+    with pytest.raises(KeyError):
+        cartesian_scenarios(
+            spending_gbp=Decimal("100000"),
+            nw_seed_gbp=Decimal("1000000"),
+            glides=("staircase", ),
+        )