"""Tests for `default_tier_pool_share` — the assumed per-parent tier share
used when no FK snapshot exists yet.

See its docstring in `app/utils/tip_predicates.py` and the "Bug A" history:
`AllocationInputLoader.load` and `PlanningService._tier_pool_left` must never
derive this differently, which is why it takes an explicit `parent_count`
now instead of always halving (a sole parent gets the whole pool, not half
of it).
"""

from app.config import settings
from app.utils.tip_predicates import default_tier_pool_share


class TestDefaultTierPoolShare:
    def test_sole_parent_gets_the_full_pool(self) -> None:
        sjuk, lagsta = default_tier_pool_share(settings.rules, parent_count=1)
        assert (sjuk, lagsta) == (390, 90)

    def test_zero_parents_is_treated_as_a_sole_parent(self) -> None:
        """Defensive: an empty workspace (shouldn't normally happen) still
        gets a sane default rather than a divide/half-of-nothing edge case."""
        sjuk, lagsta = default_tier_pool_share(settings.rules, parent_count=0)
        assert (sjuk, lagsta) == (390, 90)

    def test_two_parents_split_the_pool_in_half(self) -> None:
        sjuk, lagsta = default_tier_pool_share(settings.rules, parent_count=2)
        assert (sjuk, lagsta) == (195, 45)

    def test_more_than_two_parents_still_splits_in_half(self) -> None:
        """The domain model caps workspaces at 2 parents (see
        `WorkspaceService.add_placeholder_parent`), but this helper doesn't
        itself need to assume that cap holds -- any partnered case (>= 2)
        gets the halved share, matching FK's own per-parent allocation."""
        sjuk, lagsta = default_tier_pool_share(settings.rules, parent_count=3)
        assert (sjuk, lagsta) == (195, 45)