Cover the balance entry path and three unguarded rules

Entering a parent's Försäkringskassan balances had no tests at all, despite
being how every number in the planner originates and despite it becoming the
first thing a new user does. The scraper endpoints are pinned per test rather
than read from the ambient configuration, because a local .env sets the flag
opposite to the shipped default and a test that trusts it would pass here and
fail in CI.

Also covered: the hard expiry at twelve, whose rejection path nothing reached
and whose boundary turns out to be inclusive; and the dubbeldagar count cap,
which now drives past the limit and asserts the days beyond it fall back to a
single parent. Two weak assertions were strengthened, including one that
derived its expectation from the same response it was checking and so could
not have failed on a shared error.

backend/tests/unit/test_planning_service_apply.py

@@ -12,6 +12,9 @@ property this test file cares about most.
 from datetime import date, datetime, timedelta
 from uuid import uuid4
 
+from dateutil.relativedelta import relativedelta
+
+from app.config import settings
 from app.entities.leave_wish import LeaveWish
 from app.entities.parental_leave import ParentalLeaveFetch, TierData
 from app.entities.planned_leave import PlannedLeaveDay
@@ -500,6 +503,135 @@ class TestApplyProposedDaysValidation:
         assert rows == []
 
 
+class TestApplyProposedDaysEligibleRange:
+    """`PlanningService._validate_eligible_range` (planning_service.py:748-775)
+    rejects any planned day before the child's birth date or after
+    `birth_date + LeaveRules.hard_expiry_age_years` (the Swedish 12-year hard
+    expiry on FP days).
+
+    The upper bound is INCLUSIVE: the source only rejects `d.date >
+    hard_expiry`, so the exact 12th-birthday date itself is still eligible
+    -- confirmed by `test_hard_expiry_boundary_date_itself_is_inclusive_and_accepted`
+    below, which would fail if that boundary were ever tightened to `>=`.
+
+    `seeded_ids`' child has a fixed `birth_date` of 2024-01-01
+    (`tests/conftest.py`), which these tests rely on directly.
+    """
+
+    _BIRTH_DATE = date(2024, 1, 1)
+
+    async def test_day_after_the_hard_expiry_is_rejected(
+        self,
+        planning_service: PlanningService,
+        planned_leave_repo: SQLitePlannedLeaveRepository,
+        seeded_ids: SeededIds,
+    ) -> None:
+        ws, child, parent = (
+            seeded_ids.workspace_id,
+            seeded_ids.child_id,
+            seeded_ids.personal_data_uuid,
+        )
+        hard_expiry = self._BIRTH_DATE + relativedelta(years=settings.rules.hard_expiry_age_years)
+        day_after = hard_expiry + timedelta(days=1)
+
+        result = await planning_service.apply_proposed_days(
+            ws, [ProposedDayInput(day_after, parent, child, "sjukpenning")]
+        )
+
+        assert result.accepted is False
+        assert any(
+            r.message_key == "planApply.rejection.outsideEligibleWindow" for r in result.rejections
+        )
+        rows = await planned_leave_repo.list(parent_personal_data_uuid=parent)
+        assert rows == []
+
+    async def test_day_before_the_birth_date_is_rejected(
+        self,
+        planning_service: PlanningService,
+        planned_leave_repo: SQLitePlannedLeaveRepository,
+        seeded_ids: SeededIds,
+    ) -> None:
+        ws, child, parent = (
+            seeded_ids.workspace_id,
+            seeded_ids.child_id,
+            seeded_ids.personal_data_uuid,
+        )
+        day_before = self._BIRTH_DATE - timedelta(days=1)
+
+        result = await planning_service.apply_proposed_days(
+            ws, [ProposedDayInput(day_before, parent, child, "sjukpenning")]
+        )
+
+        assert result.accepted is False
+        assert any(
+            r.message_key == "planApply.rejection.outsideEligibleWindow" for r in result.rejections
+        )
+        rows = await planned_leave_repo.list(parent_personal_data_uuid=parent)
+        assert rows == []
+
+    async def test_hard_expiry_boundary_date_itself_is_inclusive_and_accepted(
+        self,
+        planning_service: PlanningService,
+        seeded_ids: SeededIds,
+    ) -> None:
+        """The 12th-birthday date exactly equal to `birth_date +
+        hard_expiry_age_years` is still an eligible day -- the source rejects
+        strictly-greater dates only, so this is the INCLUSIVE boundary."""
+        ws, child, parent = (
+            seeded_ids.workspace_id,
+            seeded_ids.child_id,
+            seeded_ids.personal_data_uuid,
+        )
+        hard_expiry = self._BIRTH_DATE + relativedelta(years=settings.rules.hard_expiry_age_years)
+
+        result = await planning_service.apply_proposed_days(
+            ws, [ProposedDayInput(hard_expiry, parent, child, "sjukpenning")]
+        )
+
+        assert result.accepted is True, result.rejections
+
+    async def test_birth_date_itself_is_inclusive_and_accepted(
+        self,
+        planning_service: PlanningService,
+        seeded_ids: SeededIds,
+    ) -> None:
+        ws, child, parent = (
+            seeded_ids.workspace_id,
+            seeded_ids.child_id,
+            seeded_ids.personal_data_uuid,
+        )
+
+        result = await planning_service.apply_proposed_days(
+            ws, [ProposedDayInput(self._BIRTH_DATE, parent, child, "sjukpenning")]
+        )
+
+        assert result.accepted is True, result.rejections
+
+    async def test_rejected_batch_writes_nothing_even_with_a_valid_day_included(
+        self,
+        planning_service: PlanningService,
+        planned_leave_repo: SQLitePlannedLeaveRepository,
+        seeded_ids: SeededIds,
+    ) -> None:
+        """All-or-nothing: one out-of-window day in the batch must sink the
+        whole batch, including the otherwise-valid day alongside it."""
+        ws, child, parent = (
+            seeded_ids.workspace_id,
+            seeded_ids.child_id,
+            seeded_ids.personal_data_uuid,
+        )
+        hard_expiry = self._BIRTH_DATE + relativedelta(years=settings.rules.hard_expiry_age_years)
+        day_after = hard_expiry + timedelta(days=1)
+        valid_day = ProposedDayInput(date(2026, 6, 15), parent, child, "sjukpenning")
+        invalid_day = ProposedDayInput(day_after, parent, child, "sjukpenning")
+
+        result = await planning_service.apply_proposed_days(ws, [valid_day, invalid_day])
+
+        assert result.accepted is False
+        rows = await planned_leave_repo.list(parent_personal_data_uuid=parent)
+        assert rows == []
+
+
 class TestApplyProposedDaysDeleteKeys:
     """`delete_keys` folds explicit deletions into the same validated batch as