sure/test/models/account/balance/calculator_test.rb

require "test_helper"
require "csv"

class Account::Balance::CalculatorTest < ActiveSupport::TestCase
  # See: https://docs.google.com/spreadsheets/d/18LN5N-VLq4b49Mq1fNwF7_eBiHSQB46qQduRtdAEN98/edit?usp=sharing
  setup do
    @expected_balances = CSV.read("test/fixtures/account/expected_balances.csv", headers: true).map do |row|
      {
        "date" => (Date.current + row["date_offset"].to_i.days).to_date,
        "collectable" => row["collectable"],
        "checking" => row["checking"],
        "savings_with_valuation_overrides" => row["savings_with_valuation_overrides"],
        "credit_card" => row["credit_card"],
        "multi_currency" => row["multi_currency"],

        # Balances should be calculated for all currencies of an account
        "eur_checking_eur" => row["eur_checking_eur"],
        "eur_checking_usd" => row["eur_checking_usd"]
      }
    end
  end

  test "syncs account with only valuations" do
    account = accounts(:collectable)

    calculator = Account::Balance::Calculator.new(account)
    calculator.calculate

    expected = @expected_balances.map { |row| row["collectable"].to_d }
    actual = calculator.daily_balances.map { |b| b[:balance] }

    assert_equal expected, actual
  end

  test "syncs account with only transactions" do
    account = accounts(:checking)

    calculator = Account::Balance::Calculator.new(account)
    calculator.calculate

    expected = @expected_balances.map { |row| row["checking"].to_d }
    actual = calculator.daily_balances.map { |b| b[:balance] }

    assert_equal expected, actual
  end

  test "syncs account with both valuations and transactions" do
    account = accounts(:savings_with_valuation_overrides)

    calculator = Account::Balance::Calculator.new(account)
    calculator.calculate

    expected = @expected_balances.map { |row| row["savings_with_valuation_overrides"].to_d }
    actual = calculator.daily_balances.map { |b| b[:balance] }

    assert_equal expected, actual
  end

  test "syncs liability account" do
    account = accounts(:credit_card)

    calculator = Account::Balance::Calculator.new(account)
    calculator.calculate

    expected = @expected_balances.map { |row| row["credit_card"].to_d }
    actual = calculator.daily_balances.map { |b| b[:balance] }

    assert_equal expected, actual
  end

  test "syncs foreign currency account" do
    account = accounts(:eur_checking)
    calculator = Account::Balance::Calculator.new(account)
    calculator.calculate

    # Calculator should calculate balances in both account and family currency
    expected_eur_balances = @expected_balances.map { |row| row["eur_checking_eur"].to_d }
    expected_usd_balances = @expected_balances.map { |row| row["eur_checking_usd"].to_d }

    actual_eur_balances = calculator.daily_balances.select { |b| b[:currency] == "EUR" }.sort_by { |b| b[:date] }.map { |b| b[:balance] }
    actual_usd_balances = calculator.daily_balances.select { |b| b[:currency] == "USD" }.sort_by { |b| b[:date] }.map { |b| b[:balance] }

    assert_equal expected_eur_balances, actual_eur_balances
    assert_equal expected_usd_balances, actual_usd_balances
  end

  test "syncs multi currency account" do
    account = accounts(:multi_currency)
    calculator = Account::Balance::Calculator.new(account)
    calculator.calculate

    expected_balances = @expected_balances.map { |row| row["multi_currency"].to_d }

    actual_balances = calculator.daily_balances.map { |b| b[:balance] }

    assert_equal expected_balances, actual_balances
  end

  test "syncs with overridden start date" do
    account = accounts(:multi_currency)
    account.sync
    calc_start_date = 10.days.ago.to_date
    calculator = Account::Balance::Calculator.new(account, { calc_start_date: })
    calculator.calculate

    expected_balances = @expected_balances.filter { |row| row["date"] >= calc_start_date }.map { |row| row["multi_currency"].to_d }

    actual_balances = calculator.daily_balances.map { |b| b[:balance] }

    assert_equal expected_balances, actual_balances
  end
end