Account:: namespace simplifications and cleanup (#2110)

* Flatten Holding model

* Flatten balance model

* Entries domain renames

* Fix valuations reference

* Fix trades stream

* Fix brakeman warnings

* Fix tests

* Replace existing entryable type references in DB

test/models/holding_test.rb

@@ -0,0 +1,79 @@
+require "test_helper"
+require "ostruct"
+
+class HoldingTest < ActiveSupport::TestCase
+  include EntriesTestHelper, SecuritiesTestHelper
+
+  setup do
+    @account = families(:empty).accounts.create!(name: "Test Brokerage", balance: 20000, cash_balance: 0, currency: "USD", accountable: Investment.new)
+
+    # Current day holding instances
+    @amzn, @nvda = load_holdings
+  end
+
+  test "calculates portfolio weight" do
+    expected_amzn_weight = 3240.0 / @account.balance * 100
+    expected_nvda_weight = 3720.0 / @account.balance * 100
+
+    assert_in_delta expected_amzn_weight, @amzn.weight, 0.001
+    assert_in_delta expected_nvda_weight, @nvda.weight, 0.001
+  end
+
+  test "calculates simple average cost basis" do
+    create_trade(@amzn.security, account: @account, qty: 10, price: 212.00, date: 1.day.ago.to_date)
+    create_trade(@amzn.security, account: @account, qty: 15, price: 216.00, date: Date.current)
+
+    create_trade(@nvda.security, account: @account, qty: 5, price: 128.00, date: 1.day.ago.to_date)
+    create_trade(@nvda.security, account: @account, qty: 30, price: 124.00, date: Date.current)
+
+    assert_equal Money.new((212.0 + 216.0) / 2), @amzn.avg_cost
+    assert_equal Money.new((128.0 + 124.0) / 2), @nvda.avg_cost
+  end
+
+  test "calculates total return trend" do
+    @amzn.stubs(:avg_cost).returns(Money.new(214.00))
+    @nvda.stubs(:avg_cost).returns(Money.new(126.00))
+
+    # Gained $30, or 0.93%
+    assert_equal Money.new(30), @amzn.trend.value
+    assert_in_delta 0.9, @amzn.trend.percent, 0.001
+
+    # Lost $60, or -1.59%
+    assert_equal Money.new(-60), @nvda.trend.value
+    assert_in_delta -1.6, @nvda.trend.percent, 0.001
+  end
+
+  private
+
+    def load_holdings
+      security1 = create_security("AMZN", prices: [
+        { date: 1.day.ago.to_date, price: 212.00 },
+        { date: Date.current, price: 216.00 }
+      ])
+
+      security2 = create_security("NVDA", prices: [
+        { date: 1.day.ago.to_date, price: 128.00 },
+        { date: Date.current, price: 124.00 }
+      ])
+
+      create_holding(security1, 1.day.ago.to_date, 10)
+      amzn = create_holding(security1, Date.current, 15)
+
+      create_holding(security2, 1.day.ago.to_date, 5)
+      nvda = create_holding(security2, Date.current, 30)
+
+      [ amzn, nvda ]
+    end
+
+    def create_holding(security, date, qty)
+      price = Security::Price.find_by(date: date, security: security).price
+
+      @account.holdings.create! \
+        date: date,
+        security: security,
+        qty: qty,
+        price: price,
+        amount: qty * price,
+        currency: "USD"
+    end
+end