From 68fdb5a64400850913b07b771e49d7c0894354cd Mon Sep 17 00:00:00 2001
From: JKuijperM <jkmontero17@gmail.com>
Date: Thu, 1 Oct 2026 15:10:38 +0200
Subject: [PATCH] Add tests for CSV export

---
 .../expenses/tests/test_export.py             | 547 ++++++++++++++++++
 1 file changed, 547 insertions(+)
 create mode 100644 expenses_manager/expenses/tests/test_export.py

diff --git a/expenses_manager/expenses/tests/test_export.py b/expenses_manager/expenses/tests/test_export.py
new file mode 100644
index 0000000..ce4de43
--- /dev/null
+++ b/expenses_manager/expenses/tests/test_export.py
@@ -0,0 +1,547 @@
+"""Exportación a CSV: dialectos, filtros y aislamiento por usuario.
+
+Lo que más se mira aquí es el dialecto de Excel: el BOM y la coma decimal son
+justo lo que hace que el fichero se abra con doble clic en vez de salir todo en
+una columna. Las filas se leen siempre con csv.reader y nunca con split(), que
+partiría por la mitad cualquier concepto con el delimitador dentro.
+"""
+
+import csv
+import io
+from datetime import date
+from decimal import Decimal
+
+import pytest
+from django.urls import reverse
+
+from expenses.csv_export import (
+    EXCEL_ES,
+    STANDARD,
+    csv_filename,
+    fmt_amount,
+    fmt_bool,
+    fmt_date,
+)
+from expenses.models import Account, Category, Expense, Income, Tag, Transfer
+
+pytestmark = pytest.mark.django_db
+
+
+# --------------------------------------------------------------------------
+# Utilidades
+# --------------------------------------------------------------------------
+
+
+def body(response):
+    """El cuerpo completo de una StreamingHttpResponse, como texto."""
+    return b"".join(response.streaming_content).decode("utf-8")
+
+
+def read_rows(response, delimiter=";"):
+    text = body(response).lstrip("")
+
+    return list(csv.reader(io.StringIO(text), delimiter=delimiter))
+
+
+def download(client, **params):
+    params.setdefault("fmt", "excel")
+
+    return client.get(reverse("export_download"), params)
+
+
+@pytest.fixture
+def savings(user):
+    return Account.objects.create(
+        owner=user, name="Ahorro", initial_balance=Decimal("0"), active=True
+    )
+
+
+def make_transfer(user, from_account, to_account, amount="400", on=None, fee=None):
+    transfer = Transfer(
+        owner=user,
+        date=on or date(2024, 5, 11),
+        amount=Decimal(amount),
+        from_account=from_account,
+        to_account=to_account,
+        fee_amount=Decimal(fee) if fee is not None else None,
+    )
+    transfer.sync()
+    return transfer
+
+
+# --------------------------------------------------------------------------
+# Formateo (sin base de datos ni HTTP)
+# --------------------------------------------------------------------------
+
+
+def test_excel_dialect_formats_amounts_with_a_comma():
+    assert fmt_amount(Decimal("1234.56"), EXCEL_ES) == "1234,56"
+
+
+def test_standard_dialect_formats_amounts_with_a_dot():
+    assert fmt_amount(Decimal("1234.56"), STANDARD) == "1234.56"
+
+
+def test_amounts_never_carry_a_thousands_separator():
+    # Un "1.234,56" partiría la fila en dos en el dialecto de Excel.
+    assert fmt_amount(Decimal("1234567.80"), EXCEL_ES) == "1234567,80"
+
+
+def test_amounts_always_keep_two_decimals():
+    assert fmt_amount(Decimal("5"), EXCEL_ES) == "5,00"
+
+
+def test_a_missing_amount_is_an_empty_cell_not_a_zero():
+    assert fmt_amount(None, EXCEL_ES) == ""
+
+
+def test_dates_follow_the_dialect():
+    assert fmt_date(date(2026, 1, 31), EXCEL_ES) == "31/01/2026"
+    assert fmt_date(date(2026, 1, 31), STANDARD) == "2026-01-31"
+
+
+def test_booleans_follow_the_dialect():
+    assert fmt_bool(True, EXCEL_ES) == "Sí"
+    assert fmt_bool(False, EXCEL_ES) == "No"
+    assert fmt_bool(True, STANDARD) == "true"
+    assert fmt_bool(False, STANDARD) == "false"
+
+
+def test_filename_carries_the_range():
+    name = csv_filename("gastos", date(2026, 1, 1), date(2026, 10, 1))
+
+    assert name == "gastos_2026-01-01_2026-10-01.csv"
+
+
+def test_filename_without_a_range_carries_todays_date():
+    assert csv_filename("gastos", None, None) == f"gastos_{date.today().isoformat()}.csv"
+
+
+# --------------------------------------------------------------------------
+# Las tres descargas responden
+# --------------------------------------------------------------------------
+
+
+@pytest.mark.parametrize("kind", ["expenses", "incomes", "transfers"])
+def test_every_kind_downloads_a_csv(auth_client, kind):
+    response = download(auth_client, kind=kind)
+
+    assert response.status_code == 200
+    assert response["Content-Type"] == "text/csv; charset=utf-8"
+    assert ".csv" in response["Content-Disposition"]
+
+
+def test_the_download_is_an_attachment_with_a_spanish_filename(auth_client):
+    response = download(auth_client, kind="transfers")
+
+    assert "attachment" in response["Content-Disposition"]
+    assert "traspasos_" in response["Content-Disposition"]
+
+
+def test_the_export_screen_renders(auth_client):
+    response = auth_client.get(reverse("export_index"))
+
+    assert response.status_code == 200
+    assert "form" in response.context
+
+
+def test_the_settings_page_links_to_the_export_screen(auth_client):
+    # Un {% url %} mal escrito ahí no lo ve manage.py check: revienta en runtime.
+    response = auth_client.get(reverse("settings_index"))
+
+    assert response.status_code == 200
+    assert reverse("export_index") in response.content.decode()
+
+
+def test_the_export_screen_needs_a_login(client):
+    response = client.get(reverse("export_index"))
+
+    assert response.status_code == 302
+
+
+def test_the_download_needs_a_login(client):
+    response = client.get(reverse("export_download"), {"kind": "expenses"})
+
+    assert response.status_code == 302
+
+
+# --------------------------------------------------------------------------
+# Dialectos en la salida real
+# --------------------------------------------------------------------------
+
+
+def test_excel_csv_starts_with_a_bom(auth_client, account, category):
+    Expense.objects.create(
+        owner=account.owner,
+        account=account,
+        category=category,
+        amount=Decimal("1234.56"),
+        date=date(2024, 5, 11),
+    )
+
+    response = download(auth_client, kind="expenses", fmt="excel")
+
+    assert body(response).startswith("")
+
+
+def test_standard_csv_has_no_bom(auth_client):
+    response = download(auth_client, kind="expenses", fmt="std")
+
+    assert not body(response).startswith("")
+
+
+def test_excel_csv_uses_semicolons_and_decimal_commas(auth_client, account, category):
+    Expense.objects.create(
+        owner=account.owner,
+        account=account,
+        category=category,
+        amount=Decimal("1234.56"),
+        date=date(2024, 5, 11),
+    )
+
+    rows = read_rows(download(auth_client, kind="expenses", fmt="excel"))
+
+    assert rows[0][0] == "Fecha"
+    assert rows[1][0] == "11/05/2024"
+    assert rows[1][1] == "1234,56"
+
+
+def test_standard_csv_uses_commas_and_decimal_dots(auth_client, account, category):
+    Expense.objects.create(
+        owner=account.owner,
+        account=account,
+        category=category,
+        amount=Decimal("1234.56"),
+        date=date(2024, 5, 11),
+    )
+
+    rows = read_rows(download(auth_client, kind="expenses", fmt="std"), delimiter=",")
+
+    assert rows[1][0] == "2024-05-11"
+    assert rows[1][1] == "1234.56"
+
+
+def test_a_concept_with_the_delimiter_inside_stays_in_one_cell(
+    auth_client, account, category
+):
+    Expense.objects.create(
+        owner=account.owner,
+        account=account,
+        category=category,
+        amount=Decimal("10"),
+        date=date(2024, 5, 11),
+        description="Cena; con punto y coma, y coma",
+    )
+
+    rows = read_rows(download(auth_client, kind="expenses"))
+
+    assert rows[1][5] == "Cena; con punto y coma, y coma"
+
+
+# --------------------------------------------------------------------------
+# Columnas
+# --------------------------------------------------------------------------
+
+
+def test_expense_rows_carry_parent_category_and_tags(auth_client, user, account):
+    parent = Category.objects.create(owner=user, name="Casa")
+    child = Category.objects.create(owner=user, name="Luz", parent=parent)
+    expense = Expense.objects.create(
+        owner=user,
+        account=account,
+        category=child,
+        amount=Decimal("60"),
+        date=date(2024, 5, 11),
+        description="Factura",
+    )
+    expense.tags.add(
+        Tag.objects.create(owner=user, name="fijo"),
+        Tag.objects.create(owner=user, name="hogar"),
+    )
+
+    rows = read_rows(download(auth_client, kind="expenses"))
+
+    assert rows[1][2] == "Luz"
+    assert rows[1][3] == "Casa"
+    assert rows[1][4] == account.name
+    # Unidas con | porque la coma y el ; son delimitadores en uno u otro dialecto.
+    assert sorted(rows[1][6].split("|")) == ["fijo", "hogar"]
+
+
+def test_a_top_level_category_leaves_the_parent_cell_empty(
+    auth_client, user, account, category
+):
+    Expense.objects.create(
+        owner=user,
+        account=account,
+        category=category,
+        amount=Decimal("10"),
+        date=date(2024, 5, 11),
+    )
+
+    rows = read_rows(download(auth_client, kind="expenses"))
+
+    assert rows[1][3] == ""
+
+
+def test_income_rows_carry_account_and_concept(auth_client, user, account):
+    Income.objects.create(
+        owner=user,
+        account=account,
+        name="Nómina",
+        amount=Decimal("1500"),
+        date=date(2024, 5, 11),
+    )
+
+    rows = read_rows(download(auth_client, kind="incomes"))
+
+    assert rows[0] == ["Fecha", "Importe", "Cuenta", "Concepto", "Traspaso"]
+    assert rows[1][2] == account.name
+    assert rows[1][3] == "Nómina"
+
+
+def test_transfer_rows_carry_both_accounts(auth_client, user, account, savings):
+    make_transfer(user, account, savings, amount="400")
+
+    rows = read_rows(download(auth_client, kind="transfers"))
+
+    assert rows[0] == [
+        "Fecha",
+        "Importe",
+        "Cuenta origen",
+        "Cuenta destino",
+        "Comisión",
+    ]
+    assert rows[1][1] == "400,00"
+    assert rows[1][2] == account.name
+    assert rows[1][3] == savings.name
+
+
+def test_a_transfer_without_a_fee_leaves_the_fee_cell_empty(
+    auth_client, user, account, savings
+):
+    make_transfer(user, account, savings)
+
+    rows = read_rows(download(auth_client, kind="transfers"))
+
+    # Vacío y no "0,00": un cero es un dato, y aquí el dato es "no hubo".
+    assert rows[1][4] == ""
+
+
+def test_a_transfer_with_a_fee_carries_it(auth_client, user, account, savings):
+    make_transfer(user, account, savings, fee="1.50")
+
+    rows = read_rows(download(auth_client, kind="transfers"))
+
+    assert rows[1][4] == "1,50"
+
+
+# --------------------------------------------------------------------------
+# Las patas del traspaso y la comisión: los dos avisos de la pantalla
+# --------------------------------------------------------------------------
+
+
+def test_transfer_legs_also_show_up_flagged_in_the_movement_csvs(
+    auth_client, user, account, savings
+):
+    make_transfer(user, account, savings, amount="400")
+
+    expense_rows = read_rows(download(auth_client, kind="expenses"))
+    income_rows = read_rows(download(auth_client, kind="incomes"))
+
+    # Sumar los tres ficheros duplica: esto es lo que avisa la pantalla.
+    assert [r[7] for r in expense_rows[1:]] == ["Sí"]
+    assert [r[4] for r in income_rows[1:]] == ["Sí"]
+
+
+def test_the_fee_is_exported_as_a_normal_expense(auth_client, user, account, savings):
+    make_transfer(user, account, savings, amount="400", fee="1.50")
+
+    rows = read_rows(download(auth_client, kind="expenses"))
+    by_amount = {row[1]: row for row in rows[1:]}
+
+    # La pata va marcada como traspaso; la comisión no, porque es dinero que
+    # sale de verdad del patrimonio.
+    assert by_amount["400,00"][7] == "Sí"
+    assert by_amount["1,50"][7] == "No"
+
+
+# --------------------------------------------------------------------------
+# Filtros
+# --------------------------------------------------------------------------
+
+
+def test_the_date_range_filters_both_ends(auth_client, user, account, category):
+    for day in (1, 15, 28):
+        Expense.objects.create(
+            owner=user,
+            account=account,
+            category=category,
+            amount=Decimal(day),
+            date=date(2024, 5, day),
+        )
+
+    rows = read_rows(
+        download(
+            auth_client,
+            kind="expenses",
+            date_from="2024-05-10",
+            date_to="2024-05-20",
+        )
+    )
+
+    assert [row[0] for row in rows[1:]] == ["15/05/2024"]
+
+
+def test_the_account_filter_narrows_expenses(auth_client, user, account, savings, category):
+    for target in (account, savings):
+        Expense.objects.create(
+            owner=user,
+            account=target,
+            category=category,
+            amount=Decimal("10"),
+            date=date(2024, 5, 11),
+        )
+
+    rows = read_rows(download(auth_client, kind="expenses", account=account.pk))
+
+    assert [row[4] for row in rows[1:]] == [account.name]
+
+
+def test_the_account_filter_catches_transfers_on_either_side(
+    auth_client, user, account, savings
+):
+    third = Account.objects.create(
+        owner=user, name="Bolsillo", initial_balance=Decimal("0"), active=True
+    )
+    make_transfer(user, account, savings, amount="100")
+    make_transfer(user, savings, account, amount="200")
+    make_transfer(user, savings, third, amount="300")
+
+    rows = read_rows(download(auth_client, kind="transfers", account=account.pk))
+
+    assert sorted(row[1] for row in rows[1:]) == ["100,00", "200,00"]
+
+
+def test_rows_come_out_ordered_by_date(auth_client, user, account, category):
+    for day in (28, 1, 15):
+        Expense.objects.create(
+            owner=user,
+            account=account,
+            category=category,
+            amount=Decimal("10"),
+            date=date(2024, 5, day),
+        )
+
+    rows = read_rows(download(auth_client, kind="expenses"))
+
+    assert [row[0] for row in rows[1:]] == [
+        "01/05/2024",
+        "15/05/2024",
+        "28/05/2024",
+    ]
+
+
+def test_an_inactive_account_can_still_be_chosen(auth_client, user, account, category):
+    # Se exporta histórico: una cuenta cerrada tiene movimientos que interesan.
+    account.active = False
+    account.save()
+    Expense.objects.create(
+        owner=user,
+        account=account,
+        category=category,
+        amount=Decimal("10"),
+        date=date(2024, 5, 11),
+    )
+
+    rows = read_rows(download(auth_client, kind="expenses", account=account.pk))
+
+    assert len(rows) == 2
+
+
+# --------------------------------------------------------------------------
+# Aislamiento por usuario
+# --------------------------------------------------------------------------
+
+
+def test_another_users_data_never_reaches_the_csv(
+    auth_client, user, account, category, django_user_model
+):
+    intruder = django_user_model.objects.create_user(username="otro", password="x")
+    their_account = Account.objects.create(
+        owner=intruder, name="Cuenta ajena", initial_balance=Decimal("0"), active=True
+    )
+    their_category = Category.objects.create(owner=intruder, name="Ajena")
+    Expense.objects.create(
+        owner=intruder,
+        account=their_account,
+        category=their_category,
+        amount=Decimal("999"),
+        date=date(2024, 5, 11),
+        description="No es mío",
+    )
+    Income.objects.create(
+        owner=intruder,
+        account=their_account,
+        name="Nómina ajena",
+        amount=Decimal("888"),
+        date=date(2024, 5, 11),
+    )
+    Expense.objects.create(
+        owner=user,
+        account=account,
+        category=category,
+        amount=Decimal("10"),
+        date=date(2024, 5, 11),
+        description="Mío",
+    )
+
+    expenses_csv = body(download(auth_client, kind="expenses"))
+    incomes_csv = body(download(auth_client, kind="incomes"))
+
+    assert "Mío" in expenses_csv
+    assert "No es mío" not in expenses_csv
+    assert "999" not in expenses_csv
+    assert "Nómina ajena" not in incomes_csv
+
+
+def test_another_users_account_cannot_be_used_as_a_filter(
+    auth_client, django_user_model
+):
+    intruder = django_user_model.objects.create_user(username="otro", password="x")
+    their_account = Account.objects.create(
+        owner=intruder, name="Cuenta ajena", initial_balance=Decimal("0"), active=True
+    )
+
+    response = download(auth_client, kind="expenses", account=their_account.pk)
+
+    assert response.status_code == 400
+
+
+# --------------------------------------------------------------------------
+# Parámetros inválidos
+# --------------------------------------------------------------------------
+
+
+def test_an_unknown_kind_is_rejected(auth_client):
+    assert download(auth_client, kind="everything").status_code == 400
+
+
+def test_an_unknown_format_is_rejected(auth_client):
+    assert download(auth_client, kind="expenses", fmt="pdf").status_code == 400
+
+
+def test_a_broken_date_is_rejected(auth_client):
+    response = download(auth_client, kind="expenses", date_from="ayer")
+
+    assert response.status_code == 400
+
+
+def test_an_inverted_range_is_rejected(auth_client):
+    response = download(
+        auth_client, kind="expenses", date_from="2024-05-20", date_to="2024-05-10"
+    )
+
+    # En un listado un rango invertido se ignora; aquí descargaría un fichero
+    # vacío sin explicación, así que se corta.
+    assert response.status_code == 400