Added unit test for Composite

src/test/java/org/jpatterns/gof/CompositeTest.java

@@ -0,0 +1,69 @@
+package org.jpatterns.gof;
+
+import static junit.framework.Assert.assertEquals;
+import org.junit.Test;
+
+import java.util.*;
+
+public class CompositeTest {
+  @CompositePattern.Component(participants = {DistributionList.class,
+      Person.class})
+  private static abstract class Contact {
+    public abstract void sendMail(String msg);
+
+    public void add(Contact contact) {
+    }
+
+    public void remove(Contact contact) {
+    }
+  }
+
+  @CompositePattern.Leaf
+  private static class Person extends Contact {
+    private String lastMsg;
+    private final String email;
+
+    public Person(String email) {
+      this.email = email;
+    }
+
+    public void sendMail(String msg) {
+      System.out.println("here is the message: " + msg);
+      lastMsg = msg;
+    }
+
+    private String getLastMessage() {
+      return lastMsg;
+    }
+  }
+
+  @CompositePattern.Composite(comment = "bla bla bla")
+  private static class DistributionList extends Contact {
+    private final Collection<Contact> contacts = new ArrayList<Contact>();
+
+    public void sendMail(String msg) {
+      for (Contact contact : contacts) {
+        contact.sendMail(msg);
+      }
+    }
+
+    public void add(Contact contact) {
+      contacts.add(contact);
+    }
+
+    public void remove(Contact contact) {
+      contacts.remove(contact);
+    }
+  }
+
+  @Test
+  public void personWasSentMessage() {
+    Person heinz = new Person("heinz@javaspecialists.eu");
+    Contact admins = new DistributionList();
+    admins.add(heinz);
+    Contact all = new DistributionList();
+    all.add(admins);
+    all.sendMail("hey there!");
+    assertEquals("hey there!", heinz.getLastMessage());
+  }
+}