Category overhaul (#20)

Reviewed-on: #20
Co-authored-by: Mathias <mathias2784@web.de>

tests/test_category_budget.py

@@ -0,0 +1,112 @@
+from datetime import date
+from decimal import Decimal
+
+from sqlalchemy import inspect
+from sqlalchemy.orm import Session
+
+from src.models.category import CategoryBudgetDb, CategoryDb
+from tests.factories import CategoryFactory
+
+
+def test_category_budget_schema(db_session: Session):
+    inspector = inspect(db_session.get_bind())
+    columns = {c["name"]: c for c in inspector.get_columns("category_budget")}
+
+    assert set(columns) == {
+        "id",
+        "category_id",
+        "amount_eur",
+        "valid_from",
+        "valid_to",
+    }
+    assert columns["id"]["nullable"] is False
+    assert columns["category_id"]["nullable"] is False
+    assert columns["amount_eur"]["nullable"] is False
+    assert columns["valid_from"]["nullable"] is True
+    assert columns["valid_to"]["nullable"] is True
+    assert str(columns["amount_eur"]["type"]) == "NUMERIC(12, 2)"
+
+    foreign_keys = inspector.get_foreign_keys("category_budget")
+    assert len(foreign_keys) == 1
+    assert foreign_keys[0]["constrained_columns"] == ["category_id"]
+    assert foreign_keys[0]["referred_table"] == "category"
+
+
+def test_category_budget_defaults_null_dates(db_session: Session):
+    category = CategoryDb(name=CategoryFactory.build().name)
+    db_session.add(category)
+    db_session.flush()
+
+    budget = CategoryBudgetDb(category_id=category.id, amount_eur=Decimal("150.00"))
+    db_session.add(budget)
+    db_session.commit()
+    db_session.refresh(budget)
+
+    assert budget.id is not None
+    assert budget.category_id == category.id
+    assert budget.amount_eur == Decimal("150.00")
+    # Null means unbounded in either direction.
+    assert budget.valid_from is None
+    assert budget.valid_to is None
+
+
+def test_category_budget_date_window(db_session: Session):
+    category = CategoryDb(name=CategoryFactory.build().name)
+    db_session.add(category)
+    db_session.flush()
+
+    budget = CategoryBudgetDb(
+        category_id=category.id,
+        amount_eur=Decimal("200.50"),
+        valid_from=date(2026, 10, 1),
+        valid_to=date(2026, 10, 31),
+    )
+    db_session.add(budget)
+    db_session.commit()
+    db_session.refresh(budget)
+
+    assert budget.valid_from == date(2026, 10, 1)
+    assert budget.valid_to == date(2026, 10, 31)
+
+
+def test_category_budget_relationship_both_ways(db_session: Session):
+    category = CategoryDb(name=CategoryFactory.build().name)
+    db_session.add(category)
+    db_session.flush()
+
+    budget = CategoryBudgetDb(category_id=category.id, amount_eur=Decimal("1.00"))
+    db_session.add(budget)
+    db_session.commit()
+
+    # Force re-read from the database so the relationship is loaded, not
+    # just resolved from the session identity map.
+    db_session.expire_all()
+    assert [b.id for b in category.budgets] == [budget.id]
+    assert budget.category.id == category.id
+
+
+def test_category_has_multiple_budgets(db_session: Session):
+    category = CategoryDb(name=CategoryFactory.build().name)
+    db_session.add(category)
+    db_session.flush()
+
+    budgets = [
+        CategoryBudgetDb(
+            category_id=category.id,
+            amount_eur=Decimal("1200.00"),
+            valid_from=date(2026, 10, 1),
+            valid_to=date(2026, 10, 31),
+        ),
+        CategoryBudgetDb(
+            category_id=category.id,
+            amount_eur=Decimal("1300.00"),
+            valid_from=date(2026, 11, 1),
+            valid_to=date(2026, 11, 30),
+        ),
+    ]
+    for budget in budgets:
+        db_session.add(budget)
+    db_session.commit()
+    db_session.expire_all()
+
+    assert [b.id for b in category.budgets] == [b.id for b in budgets]