task: MVVM design pattern using zkoss framework. (#1678)

* MVVM design pattern using zkoss framework.

* MVVM Design pattern updates for issues reported by SonarCloud.

* MVVM Design pattern updates for coverage issues reported by SonarCloud.

* MVVM Design pattern updates for coverage issues (removing lombok @Data)
reported by SonarCloud.

* MVVM Design pattern updates for coverage issues reported by Sonar - TEST
cases added for Equals and ToString

* MVVM Design Pattern - updating missing/todo details.

* MVVM Design Pattern - adding lombok.config

* MVVM Design Pattern - Removing xml, updating pom.xml and README as per
suggested changes in code review

* Update model-view-viewmodel/README.md

* Update model-view-viewmodel/README.md

* Update model-view-viewmodel/README.md

* Update model-view-viewmodel/README.md

* MVVM Design Pattern - Updated pom.xml and Readme based on Suggested
changes

* added type as xml

* MVVM Design Patterm - root pom.xml and module pom.xml updated

* Update pom.xml

Co-authored-by: Subhrodip Mohanta <hello@subho.xyz>
Co-authored-by: Ilkka Seppälä <iluwatar@users.noreply.github.com>

model-view-viewmodel/src/test/java/com/iluwatar/model/view/viewmodel/BookTest.java

@@ -0,0 +1,108 @@
+/*
+ * The MIT License
+ * Copyright © 2014-2021 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.model.view.viewmodel;
+
+import static org.hamcrest.CoreMatchers.is;
+import static org.hamcrest.CoreMatchers.not;
+import static org.junit.Assert.assertThat;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertNotNull;
+import static org.junit.jupiter.api.Assertions.assertNull;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+import java.util.List;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+import com.google.common.testing.EqualsTester;
+
+class BookTest {
+
+  BookViewModel bvm;
+  Book testBook;
+  List<Book> testBookList;
+  Book testBookTwo;
+  Book testBookThree;
+  
+  @BeforeEach
+  void setUp() {
+    bvm = new BookViewModel();
+    testBook = new Book("Head First Design Patterns: A Brain-Friendly Guide",
+    		"Eric Freeman, Bert Bates, Kathy Sierra, Elisabeth Robson",
+    		"Head First Design Patterns Description");
+    testBookList = bvm.getBookList();
+    testBookTwo = new Book("Head First Design Patterns: A Brain-Friendly Guide",
+	  		"Eric Freeman, Bert Bates, Kathy Sierra, Elisabeth Robson",
+	  		"Head First Design Patterns Description");
+    testBookThree = new Book("Design Patterns: Elements of Reusable Object-Oriented Software",
+            "Erich Gamma, Richard Helm, Ralph Johnson, and John Vlissides",
+            "Design Patterns Description");
+  }
+
+  @Test
+  void testBookModel() {
+	assertNotNull(testBook);
+  }
+  
+  @Test
+  void testEquals() {
+    new EqualsTester().addEqualityGroup(testBook, testBookTwo).testEquals();
+  }
+
+  @Test
+  void testToString() {
+    assertThat(testBook.toString(), is(testBookTwo.toString()));
+    assertThat(testBook.toString(), is(not(testBookThree.toString())));
+  }
+  
+  @Test
+  void testHashCode() {
+    assertTrue(testBook.equals(testBookTwo) && testBookTwo.equals(testBook));
+    assertEquals(testBook.hashCode(), testBookTwo.hashCode());
+  }
+  
+  @Test
+  void testLoadData() {
+    assertNotNull(testBookList);
+    assertTrue(testBookList.get(0).toString().contains("Head First Design Patterns"));
+  }
+
+  @Test
+  void testSelectedData() {
+	bvm.setSelectedBook(testBook);
+    assertNotNull(bvm.getSelectedBook());
+    assertEquals(testBook.toString(), bvm.getSelectedBook().toString());
+    assertTrue(true, bvm.getSelectedBook().toString());
+  }
+
+  @Test
+  void testDeleteData() {
+    bvm.setSelectedBook(testBook);
+    assertNotNull(bvm.getSelectedBook());
+    assertTrue(testBookList.get(0).toString().contains("Head First Design Patterns"));
+    bvm.deleteBook();
+    assertNull(bvm.getSelectedBook());
+    assertFalse(testBookList.get(0).toString().contains("Head First Design Patterns"));
+  }
+
+}