Add test for federal tax calculator.

app/services/federal_tax_calculator.rb

@@ -14,8 +14,8 @@ def call
   attr_accessor :income
 
   def calculate
-    bracket = FederalTaxBracket.where("bottom_range_cents <= ?", income.cents).order(:bottom_range_cents).last
-    taxable_at_bracket_rate = Money.new(income - bracket.bottom_range)
+    bracket = FederalTaxBracket.where("bottom_range_cents <= ?", income.rate_cents).order(:bottom_range_cents).last
+    taxable_at_bracket_rate = Money.new(income.rate - bracket.bottom_range)
     rated = bracket.rate * taxable_at_bracket_rate
     rated + bracket.cumulative
   end

spec/factories/federal_tax_brackets.rb

@@ -18,24 +18,24 @@
   factory :federal_tax_bracket do
     tier { "Tier 1" }
     bottom_range_cents { 0 }
-    top_range_cents { 100_000 }
+    top_range_cents { 100_000 } #$1,000.00
     rate { 0.1 }
     cumulative_cents { 0 }
 
     trait :tier_2 do
       tier { "Tier 2" }
-      bottom_range_cents { 1_000_100 }
-      top_range_cents { 10_000_000 }
+      bottom_range_cents { 100_100 } #$1,001.00
+      top_range_cents { 10_000_000 } #$100,000.00
       rate { 0.15 }
-      cumulative_cents { 200_000 }
+      cumulative_cents { 10_000 } #$100.00
     end
 
     trait :tier_3 do
       tier { "Tier 2" }
-      bottom_range_cents { 10_000_100 }
-      top_range_cents { 50_000_000 }
+      bottom_range_cents { 10_000_100 } #$100,001.00
+      top_range_cents { 50_000_000 } #$500,000.00
       rate { 0.25 }
-      cumulative_cents { 500_000 }
+      cumulative_cents { 1_485_000 } # $14,850.00
     end
 
     trait :with_all_tiers do

spec/factories/incomes.rb

@@ -26,11 +26,11 @@
       weekly_income_cents { 300_000 * 40 }
     end
 
-    # trait :with_all_types do
-    #   after :create do |_record|
-    #     create(:income, :hourly)
-    #   end
-    # end
+    trait :with_all_types do
+      after :create do |_record|
+        create(:income, :hourly)
+      end
+    end
 
     # to_create do |instance|
     #   instance.id = Income.find_or_create_by(income_type: instance.income_type).id

spec/services/federal_tax_calculator_spec.rb

@@ -0,0 +1,23 @@
+# frozen_string_literal: true
+
+require("rails_helper")
+
+RSpec.describe FederalTaxCalculator, type: :service do
+  subject(:service) do
+    described_class.call(
+      income: salary_income)
+  end
+
+  let!(:salary_income) { create(:income) }
+  let!(:tax_brackets) { create(:federal_tax_bracket, :with_all_tiers) }
+
+  it { expect(service).to be_a Money }
+
+  it "calculates federal tax" do
+    # salary_income = $50,000
+    # tax_brackets = 10% on first $1,000, 15% from $1,001 to $100,000, 25% from $100,001 to $500,000
+
+    expect(service.format).to eq("$7,449.85")
+    expect((salary_income.rate - service).format).to eq("$42,550.15")
+  end
+end