Create routes for remaining relationships

Create tests for merchant/invoice relationship
Create controller for merchants/invoices

.rspec

@@ -1,2 +1,3 @@
 --color
+--format=documentation
 --require spec_helper

app/controllers/api/v1/merchants/invoices_controller.rb

@@ -0,0 +1,5 @@
+class Api::V1::Merchants::InvoicesController < ApplicationController
+  def index
+    render json: Merchant.find(params[:merchant_id]).invoices
+  end
+end

config/routes.rb

@@ -1,21 +1,50 @@
 Rails.application.routes.draw do
 
-
-
   namespace :api do
     namespace :v1 do
-      # resources :merchants, only: [:index]
       resources :merchants, only: [:index, :show] do
         scope module: "merchants" do
           resources :items, only: [:index]
           resources :invoices, only: [:index]
         end
       end
-      resources :customers, only: [:index, :show]
-      resources :invoices, only: [:index, :show]
-      resources :items, only: [:index, :show]
-      resources :invoice_items, only: [:index, :show]
-      resources :transactions, only: [:index, :show]
+
+      resources :customers, only: [:index, :show] do
+        scope module: "customers" do
+          resources :invoices, only: [:index]
+          resources :transactions, only: [:index]
+        end
+      end
+
+      resources :invoices, only: [:index, :show] do
+        scope module: "invoices" do
+          resources :transactions, only: [:index]
+          resources :invoice_items, only: [:index]
+          resources :items, only: [:index]
+          resources :customers, only: [:index]
+          resources :merchants, only: [:index]
+        end
+      end
+
+      resources :items, only: [:index, :show] do
+        scope module: "items" do
+          resources :invoice_items, only: [:index]
+          resources :merchants, only: [:index]
+        end
+      end
+
+      resources :invoice_items, only: [:index, :show] do
+        scope module: "invoice_items" do
+          resources :invoices, only: [:index]
+          resources :items, only: [:index]
+        end
+      end
+
+      resources :transactions, only: [:index, :show] do
+        scope module: "transactions" do
+          resources :invoices, only: [:index]
+        end
+      end
     end
   end
 end

spec/factories/merchants.rb

@@ -2,4 +2,5 @@
   factory :merchant do
     name "Merchant Name"
   end
+
 end

spec/requests/api/v1/merchants/invoices_requests_spec.rb

@@ -0,0 +1,20 @@
+require 'rails_helper'
+
+describe "merchant/invoices relationship endpoints" do
+  context "get /api/v1/merchants/:merchant_id/invoices" do
+    it "returns a collection of invoices associated with that merchant" do
+        merchant = create(:merchant)
+        merchant_2 = create(:merchant)
+        create_list(:invoice, 3, merchant_id:  merchant.id)
+        create(:invoice, merchant_id: merchant_2.id)
+
+        get "/api/v1/merchants/#{merchant.id}/invoices"
+
+
+        invoices = JSON.parse(response.body)
+
+        expect(response).to be_success
+        expect(invoices.count).to eq(3)
+    end
+  end
+end

spec/requests/api/v1/merchants_request_spec.rb

@@ -25,4 +25,5 @@
       expect(merchant["id"]).to eq(id)
     end
   end
+
 end