(feature) Ensure no duplicate suppliers or agreements are created

If a supplier or agreement already exists, retrieve it rather than
creating a brand new one.

Added RuboCop exclusion for Lint/AmbiguousBlockAssociation, as per
recommmendation: rubocop/rubocop#4222

Author: leeky

.rubocop.yml

@@ -65,3 +65,8 @@ Metrics/BlockLength:
     Max: 40
     Exclude:
         - 'spec/**/*'
+
+Lint/AmbiguousBlockAssociation:
+    Exclude:
+        - 'spec/**/*'
+

lib/supplier_import_row.rb

@@ -4,9 +4,9 @@ def initialize(row)
   end
 
   def import!
-    supplier = Supplier.create!(name: @row[:suppliername])
+    supplier = Supplier.find_or_create_by!(name: @row[:suppliername])
     framework = Framework.find_by!(short_name: @row[:frameworkreference])
 
-    supplier.agreements.create!(framework: framework)
+    supplier.agreements.find_or_create_by!(framework: framework)
   end
 end

spec/factories/agreement.rb

@@ -0,0 +1,6 @@
+FactoryBot.define do
+  factory :agreement do
+    supplier
+    framework
+  end
+end

spec/lib/supplier_import_row_spec.rb

@@ -2,26 +2,28 @@
 require './lib/supplier_import_row'
 
 RSpec.describe SupplierImportRow do
+  let(:data) do
+    {
+      frameworkreference: 'RM3756',
+      supplierid: 1234,
+      suppliername: 'Bob and Bucket LLP',
+      lotid: 5678,
+      lotnumber: 1,
+      username: 'francis.brown',
+      personname: 'Francis Brown',
+      jobtitle: 'Big Cheese',
+      contacttel: '02088118055',
+      contactmobile: '07900111222',
+      email: 'francis.brown@example.com',
+      usercreationdate: '1/1/1970 18:00',
+      lastlogindate: '1/7/2018 12:40'
+    }
+  end
+
   describe '#import!' do
     it 'creates a new supplier and adds it to the framework' do
       framework = FactoryBot.create(:framework, short_name: 'RM3756')
 
-      data = {
-        frameworkreference: 'RM3756',
-        supplierid: 1234,
-        suppliername: 'Bob and Bucket LLP',
-        lotid: 5678,
-        lotnumber: 1,
-        username: 'francis.brown',
-        personname: 'Francis Brown',
-        jobtitle: 'Big Cheese',
-        contacttel: '02088118055',
-        contactmobile: '07900111222',
-        email: 'francis.brown@example.com',
-        usercreationdate: '1/1/1970 18:00',
-        lastlogindate: '1/7/2018 12:40'
-      }
-
       row = SupplierImportRow.new(data)
 
       expect { row.import! }.to change { Supplier.count }.by(1)
@@ -31,4 +33,23 @@
       expect(supplier.frameworks).to contain_exactly(framework)
     end
   end
+
+  it "doesn't create a supplier, if one already exists with that name" do
+    FactoryBot.create(:framework, short_name: 'RM3756')
+    FactoryBot.create(:supplier, name: 'Bob and Bucket LLP')
+
+    row = SupplierImportRow.new(data)
+
+    expect { row.import! }.not_to change { Supplier.count }
+  end
+
+  it "doesn't create an agreement, if one already exists between the Supplier and Framework" do
+    framework = FactoryBot.create(:framework, short_name: 'RM3756')
+    supplier = FactoryBot.create(:supplier, name: 'Bob and Bucket LLP')
+    FactoryBot.create(:agreement, framework: framework, supplier: supplier)
+
+    row = SupplierImportRow.new(data)
+
+    expect { row.import! }.not_to change { Agreement.count }
+  end
 end