Add customer destroy_spec.rb test file

spec/requests/customer/destroy_spec.rb

@@ -0,0 +1,27 @@
+# frozen_string_literal: true
+
+require 'rails_helper'
+
+RSpec.describe 'DELETE - /customer' do
+  let(:customer) { create(:customer) }
+  let(:url) { '/customers' }
+
+  describe 'DELETE /customers/:id' do
+    context 'when the customer exists' do
+      it 'deletes the customer' do
+        delete("#{url}/#{customer.id}")
+
+        expect(response).to have_http_status(:ok)
+        expect(response.parsed_body).to include('message' => 'Customer deleted!')
+      end
+    end
+
+    context 'when the customer does not exist' do
+      it 'returns 404' do
+        delete("#{url}/0")
+
+        expect(response).to have_http_status(:not_found)
+      end
+    end
+  end
+end