@Test
  public void testBuffer() {
    MessageBuffer b = new MessageBuffer();
    b.append("Hello, world");
    b.appendNewLine();
    b.append("how are you?");

    CharSequence s = b.getBuffer();
    assertEquals("Hello, world\nhow are you?", s.toString());
  }
  @Test
  public void testAppendBuffer() {
    MessageBuffer b1 = new MessageBuffer();
    b1.append("Line one");
    int l = b1.getLength();
    MessageBuffer b2 = new MessageBuffer();
    b2.append(b1);
    assertEquals("Wrong length", b2.getLength(), l);

    b2 = new MessageBuffer();
    b2.append("Some stuff");
    int l2 = b2.getLength();
    b2.append(b1);
    assertEquals("Wrong length", b2.getLength(), l + l2);
  }
 @Test
 public void testMaxSize() {
   int max = 5;
   MessageBuffer b = new MessageBuffer(5);
   for (int i = 0; i < max * 2; i++) {
     b.append("Line" + i + "\n");
   }
   String content = b.getBuffer().toString();
   String expected = "(...)\nLine5\nLine6\nLine7\nLine8\nLine9\n";
   assertEquals(expected, content);
 }