certain/backend/tests/test_budget.py

from datetime import date


def test_period_bounds_and_labels():
    from app.services import budget

    # Gehalt am 25.: September-Budget läuft 25.08.–24.09.
    assert budget.period_bounds("2026-09", 25) == (date(2026, 8, 25), date(2026, 9, 24))
    # Starttag 1: Kalendermonat.
    assert budget.period_bounds("2026-09", 1) == (date(2026, 9, 1), date(2026, 9, 30))
    # Label-Zuordnung
    assert budget.period_of(date(2026, 8, 27), 25) == "2026-09"
    assert budget.period_of(date(2026, 9, 10), 25) == "2026-09"
    assert budget.period_of(date(2026, 9, 26), 25) == "2026-10"
    assert budget.period_of(date(2026, 9, 15), 1) == "2026-09"
    assert budget.shift_label("2026-09", 1) == "2026-10"
    assert budget.shift_label("2026-01", -1) == "2025-12"


def _lebensmittel(admin):
    groups = admin.get("/api/categories").json()
    for g in groups:
        for c in g["categories"]:
            if c["name"] == "Lebensmittel":
                return c["id"]
    raise AssertionError("Lebensmittel-Kategorie fehlt")


def _gehalt(admin):
    groups = admin.get("/api/categories").json()
    for g in groups:
        for c in g["categories"]:
            if c["name"] == "Gehalt":
                return c["id"]
    raise AssertionError("Gehalt-Kategorie fehlt")


def test_budget_soll_ist_and_override(admin):
    # Starttag 1 -> aktueller Zeitraum = Kalendermonat, heutige Buchungen zählen.
    admin.put("/api/settings/budget_start_day", params={"value": "1"})
    today = date.today()
    label = f"{today.year:04d}-{today.month:02d}"

    acc = admin.post("/api/accounts", json={"name": "Budgetkonto", "currency": "EUR"}).json()
    leb = _lebensmittel(admin)

    # Standard-Budget für Lebensmittel: 500,00 EUR.
    admin.put(f"/api/budget/template/category/{leb}", params={"planned_cents": 50000})

    # Ausgabe 300,00 EUR heute.
    admin.post("/api/transactions", json={"type": "expense", "date": str(today), "account_id": acc["id"], "amount_cents": 30000, "category_id": leb})

    v = admin.get("/api/budget/current").json()
    row = next(c for g in v["groups"] for c in g["categories"] if c["category_id"] == leb)
    assert row["planned_cents"] == 50000
    assert row["actual_cents"] == 30000
    assert row["over"] is False
    assert v["customized"] is False

    # Noch 300 EUR -> insgesamt 600 > 500 -> über Budget.
    admin.post("/api/transactions", json={"type": "expense", "date": str(today), "account_id": acc["id"], "amount_cents": 30000, "category_id": leb})
    v = admin.get(f"/api/budget/{label}").json()
    row = next(c for g in v["groups"] for c in g["categories"] if c["category_id"] == leb)
    assert row["actual_cents"] == 60000
    assert row["over"] is True

    # Monats-Override auf 700 EUR -> nicht mehr über Budget, Monat individualisiert.
    v = admin.put(f"/api/budget/{label}/category/{leb}", params={"planned_cents": 70000}).json()
    row = next(c for g in v["groups"] for c in g["categories"] if c["category_id"] == leb)
    assert row["planned_cents"] == 70000
    assert row["over"] is False
    assert v["customized"] is True

    # Vorlage bleibt unverändert.
    tpl = admin.get("/api/budget/template").json()
    tpl_leb = next(l for l in tpl["lines"] if l["category_id"] == leb)
    assert tpl_leb["planned_cents"] == 50000

    # Zurücksetzen -> wieder Vorlagenwert, nicht mehr individualisiert.
    v = admin.delete(f"/api/budget/{label}").json()
    row = next(c for g in v["groups"] for c in g["categories"] if c["category_id"] == leb)
    assert row["planned_cents"] == 50000
    assert v["customized"] is False


def test_budget_copy_month_and_template(admin):
    admin.put("/api/settings/budget_start_day", params={"value": "1"})
    today = date.today()
    label = f"{today.year:04d}-{today.month:02d}"
    leb = _lebensmittel(admin)

    admin.put(f"/api/budget/template/category/{leb}", params={"planned_cents": 50000})
    # Monat individuell auf 700.
    admin.put(f"/api/budget/{label}/category/{leb}", params={"planned_cents": 70000})

    # Monat -> Vorlage: Vorlage übernimmt den 700er Wert.
    r = admin.post(f"/api/budget/template/from-month/{label}")
    assert r.status_code == 200, r.text
    tpl = r.json()
    assert next(l for l in tpl["lines"] if l["category_id"] == leb)["planned_cents"] == 70000

    # Vorlage auf 900 ändern, dann Vorlage -> Monat (überschreibt den angepassten Monat).
    admin.put(f"/api/budget/template/category/{leb}", params={"planned_cents": 90000})
    v = admin.post(f"/api/budget/{label}/from-template").json()
    row = next(c for g in v["groups"] for c in g["categories"] if c["category_id"] == leb)
    assert row["planned_cents"] == 90000
    assert v["customized"] is True


def test_planned_income(admin):
    admin.put("/api/settings/budget_start_day", params={"value": "1"})
    today = date.today()
    acc = admin.post("/api/accounts", json={"name": "Lohnkonto", "currency": "EUR"}).json()
    gehalt = _gehalt(admin)

    r = admin.post("/api/budget/income", json={
        "label": "Gehalt", "category_id": gehalt, "target_account_id": acc["id"], "planned_cents": 300000,
    })
    assert r.status_code == 201

    # Tatsächliche Einnahme 3000 EUR.
    admin.post("/api/transactions", json={"type": "income", "date": str(today), "account_id": acc["id"], "amount_cents": 300000, "category_id": gehalt})

    v = admin.get("/api/budget/current").json()
    line = next(i for i in v["income"] if i["label"] == "Gehalt")
    assert line["planned_cents"] == 300000
    assert line["received_cents"] == 300000
    assert v["totals"]["planned_income"] >= 300000