Basic Account Balance Sync Algorithm (#501)

* Sketch out sync interface

* Add basic account sync algorithm

* Update logic for final balance in series

* Remove start_date concept

* Clean up tests

* Improve clarity of test

* Update app/models/account.rb

Co-authored-by: Rob Zolkos <rob@zolkos.com>
Signed-off-by: Zach Gollwitzer <zach.gollwitzer@gmail.com>

* Update app/models/transaction.rb

Co-authored-by: Rob Zolkos <rob@zolkos.com>
Signed-off-by: Zach Gollwitzer <zach.gollwitzer@gmail.com>

* Update app/models/valuation.rb

Co-authored-by: Rob Zolkos <rob@zolkos.com>
Signed-off-by: Zach Gollwitzer <zach.gollwitzer@gmail.com>

* Re-organize code, simplify job interface

* Consolidate balance calculations

* More cleanup

---------

Signed-off-by: Zach Gollwitzer <zach.gollwitzer@gmail.com>
Co-authored-by: Rob Zolkos <rob@zolkos.com>

test/fixtures/account/depositories.yml

@@ -1 +1,2 @@
 checking: {}
+savings: {}

test/fixtures/accounts.yml

@@ -5,10 +5,10 @@ generic:
   balance: 1200
 
 # Account with only valuations
-collectible:
+collectable:
   family: dylan_family
-  name: Collectible Account
-  balance: 500
+  name: Collectable Account
+  balance: 550
 
 # Account with only transactions
 checking:

test/fixtures/transactions.yml

@@ -25,7 +25,7 @@ checking_four:
 
 checking_five:
   name: Netflix
-  date: <%= 30.days.ago.to_date %>
+  date: <%= 29.days.ago.to_date %>
   amount: 15
   account: checking
 
@@ -50,6 +50,6 @@ savings_three:
 
 savings_four:
   name: Check Deposit
-  date: <%= 30.days.ago.to_date %>
+  date: <%= 29.days.ago.to_date %>
   amount: -500
   account: savings_with_valuation_overrides

test/fixtures/valuations.yml

@@ -1,18 +1,18 @@
-# For collectible account that only has valuations (no transactions)
-collectible_one:
+# For collectable account that only has valuations (no transactions)
+collectable_one:
   value: 550
   date: <%= 4.days.ago.to_date %>
-  account: collectible
+  account: collectable
 
-collectible_two:
+collectable_two:
   value: 700
   date: <%= 12.days.ago.to_date %>
-  account: collectible
+  account: collectable
 
-collectible_three:
+collectable_three:
   value: 400
   date: <%= 30.days.ago.to_date %>
-  account: collectible
+  account: collectable
 
 # For checking account that has valuations and transactions
 savings_one:
@@ -24,3 +24,8 @@ savings_two:
   value: 19500
   date: <%= 12.days.ago.to_date %>
   account: savings_with_valuation_overrides
+
+savings_three:
+  value: 21000
+  date: <%= 25.days.ago.to_date %>
+  account: savings_with_valuation_overrides

test/models/account/balance_calculator_test.rb

@@ -0,0 +1,50 @@
+require "test_helper"
+
+class Account::BalanceCalculatorTest < ActiveSupport::TestCase
+    test "syncs account with only valuations" do
+        account = accounts(:collectable)
+        account.accountable = account_other_assets(:one)
+
+        daily_balances = Account::BalanceCalculator.new(account).daily_balances
+
+        expected_balances = [
+            400, 400, 400, 400, 400, 400, 400, 400, 400, 400,
+            400, 400, 400, 400, 400, 400, 400, 400, 700, 700,
+            700, 700, 700, 700, 700, 700, 550, 550, 550, 550,
+            550
+        ].map(&:to_d)
+
+        assert_equal expected_balances, daily_balances.map { |b| b[:balance] }
+    end
+
+    test "syncs account with only transactions" do
+        account = accounts(:checking)
+        account.accountable = account_depositories(:checking)
+
+        daily_balances = Account::BalanceCalculator.new(account).daily_balances
+
+        expected_balances = [
+            4000, 3985, 3985, 3985, 3985, 3985, 3985, 3985, 5060, 5060,
+            5060, 5060, 5060, 5060, 5060, 5040, 5040, 5040, 5010, 5010,
+            5010, 5010, 5010, 5010, 5010, 5000, 5000, 5000, 5000, 5000,
+            5000
+        ].map(&:to_d)
+
+        assert_equal expected_balances, daily_balances.map { |b| b[:balance] }
+    end
+
+    test "syncs account with both valuations and transactions" do
+        account = accounts(:savings_with_valuation_overrides)
+        account.accountable = account_depositories(:savings)
+        daily_balances = Account::BalanceCalculator.new(account).daily_balances
+
+        expected_balances = [
+            21250, 21750, 21750, 21750, 21750, 21000, 21000, 21000, 21000, 21000,
+            21000, 21000, 19000, 19000, 19000, 19000, 19000, 19000, 19500, 19500,
+            19500, 19500, 19500, 19500, 19500, 19700, 19700, 20500, 20500, 20500,
+            20000
+        ].map(&:to_d)
+
+        assert_equal expected_balances, daily_balances.map { |b| b[:balance] }
+    end
+end

test/models/account/syncable_test.rb

@@ -0,0 +1,32 @@
+require "test_helper"
+
+class Account::SyncableTest < ActiveSupport::TestCase
+    test "account has no balances until synced" do
+        account = accounts(:savings_with_valuation_overrides)
+        account.accountable = account_depositories(:savings)
+
+        assert_equal 0, account.balances.count
+    end
+
+    test "account has balances after syncing" do
+        account = accounts(:savings_with_valuation_overrides)
+        account.accountable = account_depositories(:savings)
+        account.sync
+
+        assert_equal 31, account.balances.count
+    end
+
+    test "stale balances are purged after syncing" do
+        account = accounts(:savings_with_valuation_overrides)
+        account.accountable = account_depositories(:savings)
+
+        # Create old, stale balances that should be purged (since they are before account start date)
+        account.balances.create!(date: 1.year.ago, balance: 1000)
+        account.balances.create!(date: 2.years.ago, balance: 2000)
+        account.balances.create!(date: 3.years.ago, balance: 3000)
+
+        account.sync
+
+        assert_equal 31, account.balances.count
+    end
+end