Add partial account sync support (#653)

* Add partial account sync support

* Fix indentation

* Use historical balance as base when doing partial sync

* Simplify controller crud tests

* Fix linter errors

test/models/account/syncable_test.rb

@@ -1,38 +1,81 @@
 require "test_helper"
 
 class Account::SyncableTest < ActiveSupport::TestCase
-    test "account has no balances until synced" do
-        account = accounts(:savings_with_valuation_overrides)
+  test "account has no balances until synced" do
+    account = accounts(:savings_with_valuation_overrides)
 
-        assert_equal 0, account.balances.count
-    end
+    assert_equal 0, account.balances.count
+  end
 
-    test "account has balances after syncing" do
-        account = accounts(:savings_with_valuation_overrides)
-        account.sync
+  test "account has balances after syncing" do
+    account = accounts(:savings_with_valuation_overrides)
+    account.sync
 
-        assert_equal 31, account.balances.count
-    end
+    assert_equal 31, account.balances.count
+  end
 
-    test "foreign currency account has balances in each currency after syncing" do
-        account = accounts(:eur_checking)
-        account.sync
+  test "partial sync with missing historical balances performs a full sync" do
+    account = accounts(:savings_with_valuation_overrides)
+    account.sync 10.days.ago.to_date
 
-        assert_equal 62, account.balances.count
-        assert_equal 31, account.balances.where(currency: "EUR").count
-        assert_equal 31, account.balances.where(currency: "USD").count
-    end
+    assert_equal 31, account.balances.count
+  end
 
-    test "stale balances are purged after syncing" do
-        account = accounts(:savings_with_valuation_overrides)
+  test "balances are updated after syncing" do
+    account = accounts(:savings_with_valuation_overrides)
+    balance_date = 10.days.ago
+    account.balances.create!(date: balance_date, balance: 1000)
+    account.sync
 
-        # 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)
+    assert_equal 19500, account.balances.find_by(date: balance_date)[:balance]
+  end
 
-        account.sync
+  test "balances before sync start date are not updated after syncing" do
+    account = accounts(:savings_with_valuation_overrides)
+    balance_date = 10.days.ago
+    account.balances.create!(date: balance_date, balance: 1000)
+    account.sync 5.days.ago.to_date
 
-        assert_equal 31, account.balances.count
-    end
+    assert_equal 1000, account.balances.find_by(date: balance_date)[:balance]
+  end
+
+  test "balances after sync start date are updated after syncing" do
+    account = accounts(:savings_with_valuation_overrides)
+    balance_date = 10.days.ago
+    account.balances.create!(date: balance_date, balance: 1000)
+    account.sync 20.days.ago.to_date
+
+    assert_equal 19500, account.balances.find_by(date: balance_date)[:balance]
+  end
+
+  test "balance on the sync date is updated after syncing" do
+    account = accounts(:savings_with_valuation_overrides)
+    balance_date = 5.days.ago
+    account.balances.create!(date: balance_date, balance: 1000)
+    account.sync balance_date.to_date
+
+    assert_equal 19700, account.balances.find_by(date: balance_date)[:balance]
+  end
+
+  test "foreign currency account has balances in each currency after syncing" do
+    account = accounts(:eur_checking)
+    account.sync
+
+    assert_equal 62, account.balances.count
+    assert_equal 31, account.balances.where(currency: "EUR").count
+    assert_equal 31, account.balances.where(currency: "USD").count
+  end
+
+  test "stale balances are purged after syncing" do
+    account = accounts(:savings_with_valuation_overrides)
+
+    # 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