Inclusion of log4j dependency rather than relying on

System.out.println() statements.
Added unit tests for doa module.

dao/src/test/java/com/iluwatar/dao/AppTest.java

@@ -1,19 +0,0 @@
-package com.iluwatar.dao;
-
-import org.junit.Test;
-
-import com.iluwatar.dao.App;
-
-/**
- * 
- * Application test
- *
- */
-public class AppTest {
-
-	@Test
-	public void test() {
-		String[] args = {};
-		App.main(args);
-	}
-}

dao/src/test/java/com/iluwatar/dao/CustomerDaoImplTest.java

@@ -0,0 +1,81 @@
+package com.iluwatar.dao;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertNull;
+import static org.junit.Assert.assertTrue;
+
+import java.util.ArrayList;
+import java.util.List;
+
+import org.junit.Before;
+import org.junit.Test;
+
+public class CustomerDaoImplTest {
+
+	private CustomerDaoImpl impl;
+	private List<Customer> customers;
+	private static final Customer CUSTOMER = new Customer(1, "Freddy", "Kruger");
+	
+	@Before
+	public void setUp() {
+		customers = new ArrayList<Customer>();
+		customers.add(CUSTOMER);
+		impl = new CustomerDaoImpl(customers);
+	}
+	
+	@Test
+	public void deleteExistingCustomer() {
+		assertEquals(1, impl.getAllCustomers().size());
+		impl.deleteCustomer(CUSTOMER);
+		assertTrue(impl.getAllCustomers().isEmpty());
+	}
+	
+	@Test
+	public void deleteNonExistingCustomer() {
+		final Customer nonExistingCustomer = new Customer(2, "Robert", "Englund");
+		impl.deleteCustomer(nonExistingCustomer);
+		assertEquals(1, impl.getAllCustomers().size());
+	}
+	
+	@Test
+	public void updateExistingCustomer() {
+		final String newFirstname = "Bernard";
+		final String newLastname = "Montgomery";
+		final Customer customer = new Customer(CUSTOMER.getId(), newFirstname, newLastname);
+		impl.updateCustomer(customer);
+		final Customer cust = impl.getCustomerById(CUSTOMER.getId());
+		assertEquals(newFirstname, cust.getFirstName());
+		assertEquals(newLastname, cust.getLastName());
+	}
+	
+	@Test
+	public void updateNonExistingCustomer() {
+		final int nonExistingId = 999;
+		final String newFirstname = "Douglas";
+		final String newLastname = "MacArthur";
+		final Customer customer = new Customer(nonExistingId, newFirstname, newLastname);
+		impl.updateCustomer(customer);
+		assertNull(impl.getCustomerById(nonExistingId));
+		final Customer existingCustomer = impl.getCustomerById(CUSTOMER.getId());
+		assertEquals(CUSTOMER.getFirstName(), existingCustomer.getFirstName());
+		assertEquals(CUSTOMER.getLastName(), existingCustomer.getLastName());
+	}
+	
+	@Test
+	public void addCustomer() {
+		final Customer newCustomer = new Customer(3, "George", "Patton");
+		impl.addCustomer(newCustomer);
+		assertEquals(2, impl.getAllCustomers().size());
+	}
+	
+	@Test
+	public void getExistinCustomerById() {
+		assertEquals(CUSTOMER, impl.getCustomerById(CUSTOMER.getId()));
+	}
+	
+	@Test
+	public void getNonExistinCustomerById() {
+		final int nonExistingId = 999;
+		assertNull(impl.getCustomerById(nonExistingId));
+	}
+}

dao/src/test/java/com/iluwatar/dao/CustomerTest.java

@@ -0,0 +1,87 @@
+package com.iluwatar.dao;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertFalse;
+import static org.junit.Assert.assertTrue;
+
+import org.junit.Before;
+import org.junit.Test;
+
+public class CustomerTest {
+
+	private Customer customer;
+	private static final int ID = 1;
+	private static final String FIRSTNAME = "Winston";
+	private static final String LASTNAME = "Churchill";
+	
+	@Before
+	public void setUp() {
+		customer = new Customer(ID, FIRSTNAME, LASTNAME);
+	}
+	
+	@Test
+	public void getIndex() {
+		assertEquals(ID, customer.getId());
+	}
+	
+	@Test
+	public void getFirstname() {
+		assertEquals(FIRSTNAME, customer.getFirstName());
+	}
+	
+	@Test
+	public void getLastname() {
+		assertEquals(LASTNAME, customer.getLastName());
+	}
+	
+	@Test
+	public void setIndex() {
+		final int newId = 2;
+		customer.setId(newId);
+		assertEquals(newId, customer.getId());
+	}
+	
+	@Test
+	public void setFirstname() {
+		final String newFirstname = "Bill";
+		customer.setFirstName(newFirstname);
+		assertEquals(newFirstname, customer.getFirstName());
+	}
+	
+	@Test
+	public void setLastname() {
+		final String newLastname = "Clinton";
+		customer.setLastName(newLastname);
+		assertEquals(newLastname, customer.getLastName());
+	}
+	
+	@Test
+	public void equalsWithDifferentId() {
+		final int newId = 2;
+		final Customer otherCustomer = new Customer(newId, FIRSTNAME, LASTNAME);
+		assertFalse(customer.equals(otherCustomer));
+	}
+	
+	@Test
+	public void equalsWithSameObjects() {
+		final Customer otherCustomer = new Customer(ID, FIRSTNAME, LASTNAME);
+		assertTrue(customer.equals(otherCustomer));
+	}
+	
+	@Test
+	public void testHashCode() {
+		assertTrue(customer.hashCode() > 0);
+	}
+	
+	@Test
+	public void testToString() {
+		final StringBuffer buffer = new StringBuffer();
+		buffer.append("Customer{id=");
+        buffer.append(""+customer.getId());
+        buffer.append(", firstName='");
+        buffer.append(customer.getFirstName());
+        buffer.append("\', lastName='");
+        buffer.append(customer.getLastName() + "\'}");
+		assertEquals(buffer.toString(), customer.toString());
+	}
+}

dao/src/test/resources/log4j.xml

@@ -0,0 +1,17 @@
+<?xml version="1.0" encoding="UTF-8" ?>
+<!DOCTYPE log4j:configuration SYSTEM "log4j.dtd">
+<log4j:configuration debug="true"
+	xmlns:log4j='http://jakarta.apache.org/log4j/'>
+
+	<appender name="console" class="org.apache.log4j.ConsoleAppender">
+		<layout class="org.apache.log4j.PatternLayout">
+			<param name="ConversionPattern" value="%d{yyyy-MM-dd HH:mm:ss} %-5p %c{1}:%L - %m%n" />
+		</layout>
+	</appender>
+
+	<root>
+		<level value="INFO" />
+		<appender-ref ref="console" />
+	</root>
+
+</log4j:configuration>