@Override
  public String toString() {
    StringBuilder builder = new StringBuilder("AfterAll.of(");
    Joiner.on(", ").appendTo(builder, subTriggers);
    builder.append(")");

    return builder.toString();
  }
@Test
  public void testToString() {
    Trigger trigger = AfterAll.of(StubTrigger.named("t1"), StubTrigger.named("t2"));
    assertEquals("AfterAll.of(t1, t2)", trigger.toString());
  }