public void ChangeToStringImperativ() { using (ProductionDataContext db = new ProductionDataContext()) { List <ProductVendor> vendorList = db.GetFirstNProductVendor(20); List <Product> productList = db.GetFirstNProducts(20); string result = productList.ChangeToStringImperativ(vendorList); string firstPair = result.Substring(0, result.IndexOf('\n') - 1); Assert.AreEqual("Adjustable Race-Litware, Inc.", firstPair); } }