feat(fase2a): percent-mål mot baseline 0 reiser ValueError (S2.0)

src/portfolio_optimiser/run.py

@@ -420,6 +420,12 @@ def _goal_limit_if_reached(goal: GoalContract, observed_ore: int, baseline_ore:
     if goal.absolute_ore is not None and observed_ore >= goal.absolute_ore:
         return goal.absolute_ore
     if goal.percent is not None:
+        if baseline_ore <= 0:
+            raise ValueError(
+                f"percent goal ({goal.percent}%) is meaningless against a non-positive baseline "
+                f"({baseline_ore} øre): int(percent/100 * 0) == 0 would falsely read as 'goal "
+                "reached'. Supply an absolute_ore target, or ensure the addressable baseline is > 0."
+            )
         threshold = int(goal.percent / 100 * baseline_ore)
         if observed_ore >= threshold:
             return threshold

tests/test_portfolio_learning_loadbearing.py

@@ -18,8 +18,11 @@ from __future__ import annotations
 
 from importlib.resources import files
 
+import pytest
+
+from portfolio_optimiser.contracts import GoalContract
 from portfolio_optimiser.reference_domain import Project
-from portfolio_optimiser.run import run_portfolio
+from portfolio_optimiser.run import _goal_limit_if_reached, run_portfolio
 from portfolio_optimiser.verdicts import ProposalFeatures, capture_verdict, write_verdict
 
 _MINI_BUNDLE = str(files("portfolio_optimiser").joinpath("data/bundles/bygg-energi-mikro-a"))
@@ -166,3 +169,16 @@ async def test_dropped_verdict_in_kplus1_inbox_reaches_store(
         "a verdict dropped as a file in k+1's verdict_dir inbox did not reach the store — the "
         "verdict_dir threading in run_portfolio is detached"
     )
+
+
+def test_percent_goal_against_zero_baseline_raises_value_error() -> None:
+    """T-2.0c (direct unit test of the chokepoint): a percent goal against a non-positive baseline is
+    meaningless — ``int(percent/100 * 0) == 0`` would falsely read as 'goal reached'. The guard in
+    ``_goal_limit_if_reached`` raises ``ValueError`` instead. Detach the guard → no raise (false
+    'reached') → RED. Tested DIRECTLY on the function: ``_goal_limit_if_reached`` is only called
+    inside a non-empty loop with ``baseline=sum(total_cost)``, and no reference project has zero
+    cost, so a baseline-0 path is not constructable via ``run_portfolio`` — the direct call is the
+    unambiguous, constructable test."""
+    goal = GoalContract(percent=10.0)
+    with pytest.raises(ValueError):
+        _goal_limit_if_reached(goal, observed_ore=0, baseline_ore=0)