Added tests for service-layer pattern

service-layer/src/main/java/com/iluwatar/servicelayer/common/BaseEntity.java

@@ -12,8 +12,37 @@ import javax.persistence.Version;
  */
 @MappedSuperclass
 @Inheritance(strategy = InheritanceType.TABLE_PER_CLASS)
-public class BaseEntity {
+public abstract class BaseEntity {
 
   @Version
   private Long version;
+
+  /**
+   * Indicates the unique id of this entity
+   *
+   * @return The id of the entity, or 'null' when not persisted
+   */
+  public abstract Long getId();
+
+  /**
+   * Set the id of this entity
+   *
+   * @param id The new id
+   */
+  public abstract void setId(Long id);
+
+  /**
+   * Get the name of this entity
+   *
+   * @return The name of the entity
+   */
+  public abstract String getName();
+
+  /**
+   * Set the name of this entity
+   *
+   * @param name The new name
+   */
+  public abstract void setName(final String name);
+
 }