単体テストの実行について

###前提・実現したいこと
単体テストを行いたいたいのですが、実行がうまくできません。
idを抽出して、numberに入っている値と同じか確認するにはどうすればいいですか?

###該当のソースコード
`単体テスト
import org.junit.Test;
import org.sasami.tcm.bean.CustomerBean;

import junit.framework.TestCase;

public class CustomerSearchTest extends TestCase{

public CustomerSearchTest(String Id) {
		super(Id);

}

@Test
public void testSearch() {
	String Id = null;
	CustomerSearch customersearch = new CustomerSearch();
	CustomerBean  number = customersearch.search(Id);

		assertEquals(Id, number);
    }

}

継承クラス
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;

import org.sasami.tcm.bean.CustomerBean;

public class CustomerSearch {

public CustomerBean search (String Id) {
 	Connection connection =null;
	PreparedStatement preparedStatement =null;
	ResultSet resultSet =null;
	CustomerBean customerBean = new CustomerBean();
try {
	
            Class.forName("org.postgresql.Driver");
            connection = DriverManager.getConnection(
            		 "jdbc:postgresql://localhost/postgres", "postgres1", "postgres");
            String SQL = "SELECT ID, PASSWORD"
    				+ "ADDRESS, TEL TB_CUSTOMER "
    				+ "WHERE ID = ?";

            preparedStatement = connection.prepareStatement(SQL);

            preparedStatement.setString(1, Id);

            resultSet = preparedStatement.executeQuery();

            while(resultSet.next()){
            	customerBean.setId(resultSet.getInt("ID"));
            	customerBean.setUserid(resultSet.getString("USERID"));
            	customerBean.setPassword(resultSet.getString("PASSWORD"));
            	customerBean.setFamilyname(resultSet.getString("FAMILYNAME"));
            	customerBean.setFirstname(resultSet.getString("FIRSTNAME"));
            	customerBean.setFamilyfuri(resultSet.getString("FAMILYFURI"));
            	customerBean.setFirstfuri(resultSet.getString("FIRSTFURI"));
            	customerBean.setEmail(resultSet.getString("EMAIL"));
            	customerBean.setZipcd(resultSet.getString("ZIPCD"));
            	customerBean.setAddress(resultSet.getString("ADDRESS"));
            	customerBean.setTel(resultSet.getString("TEL"));
            }

			} catch (Exception e) {
				e.printStackTrace();
			}finally{
				try{
					if(resultSet != null){
						resultSet.close();
					}
					if(preparedStatement != null){
						preparedStatement.close();
					}
					if(connection != null){
						connection.close();
					}
				}catch (Exception e) {
					e.printStackTrace();
				}
			}
			return customerBean;
	}

}