supplier_spec: add sync from file test

spec/models/supplier_spec.rb

@@ -3,6 +3,21 @@ require_relative '../spec_helper'
 describe Supplier do
   let(:supplier) { create :supplier }
 
+  context 'syncs from file' do
+    it 'imports and updates articles' do
+      article1 = create(:article, supplier: supplier, order_number: 177813, unit: '250 g', price: 0.1)
+      article2 = create(:article, supplier: supplier, order_number: 12345)
+      supplier.articles = [article1, article2]
+      options = { filename: "foodsoft_file_01.csv" }
+      options[:outlist_absent] = true
+      options[:convert_units] = true
+      updated_article_pairs, outlisted_articles, new_articles = supplier.sync_from_file( Rails.root.join("spec/fixtures/foodsoft_file_01.csv"), options)
+      expect(new_articles.length).to be > 0
+      expect(updated_article_pairs.first[1][:name]).to eq "Tomaten"
+      expect(outlisted_articles.first).to eq article2
+    end
+  end
+
   it 'return correct tolerance' do
     supplier = create :supplier, articles: create_list(:article, 1, unit_quantity: 1)
     expect(supplier.has_tolerance?).to be false