public String getContext() {
    return context;
  }
@Test
  public void testBuilderAppend() {
    Configuration conf = new Configuration();
    conf.set(HADOOP_CALLER_CONTEXT_SEPARATOR_KEY, "$");
    CallerContext.Builder builder = new CallerContext.Builder(null, conf);
    CallerContext context = builder.append("context1")
        .append("context2").append("key3", "value3").build();
    Assert.assertEquals(true,
        context.getContext().contains("$"));
    String[] items = context.getContext().split("\\$");
    Assert.assertEquals(3, items.length);
    Assert.assertEquals("key3:value3", items[2]);

    builder.append("$$");
    Assert.assertEquals("context1$context2$key3:value3$$$",
        builder.build().getContext());
  }