Merge data transfer object examples (#1635)

* #1617 merge dto pattern examples

* #1617 update license headers

Co-authored-by: Subhrodip Mohanta <subhrodipmohanta@gmail.com>

data-transfer-object/src/test/java/com/iluwatar/datatransfer/customer/CustomerResourceTest.java

@@ -0,0 +1,77 @@
+/*
+ * The MIT License
+ * Copyright © 2014-2019 Ilkka Seppälä
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+package com.iluwatar.datatransfer.customer;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+import java.util.ArrayList;
+import java.util.List;
+
+import com.iluwatar.datatransfer.customer.CustomerDto;
+import com.iluwatar.datatransfer.customer.CustomerResource;
+import org.junit.jupiter.api.Test;
+
+/**
+ * tests {@link CustomerResource}.
+ */
+public class CustomerResourceTest {
+  @Test
+  public void shouldGetAllCustomers() {
+    var customers = List.of(new CustomerDto("1", "Melody", "Yates"));
+    var customerResource = new CustomerResource(customers);
+    var allCustomers = customerResource.getAllCustomers();
+
+    assertEquals(1, allCustomers.size());
+    assertEquals("1", allCustomers.get(0).getId());
+    assertEquals("Melody", allCustomers.get(0).getFirstName());
+    assertEquals("Yates", allCustomers.get(0).getLastName());
+  }
+
+  @Test
+  public void shouldSaveCustomer() {
+    var customer = new CustomerDto("1", "Rita", "Reynolds");
+    var customerResource = new CustomerResource(new ArrayList<>());
+
+    customerResource.save(customer);
+
+    var allCustomers = customerResource.getAllCustomers();
+    assertEquals("1", allCustomers.get(0).getId());
+    assertEquals("Rita", allCustomers.get(0).getFirstName());
+    assertEquals("Reynolds", allCustomers.get(0).getLastName());
+  }
+
+  @Test
+  public void shouldDeleteCustomer() {
+    var customer = new CustomerDto("1", "Terry", "Nguyen");
+    var customers = new ArrayList<>(List.of(customer));
+    var customerResource = new CustomerResource(customers);
+
+    customerResource.delete(customer.getId());
+
+    var allCustomers = customerResource.getAllCustomers();
+    assertTrue(allCustomers.isEmpty());
+  }
+
+}