### Question:
ImmutablePair { @Override public String toString() { return Objects.toStringHelper(this) .add("first", first) .add("second", second) .toString(); } ImmutablePair(A first, B second); static ImmutablePair<A, B> of(A first, B second); A getFirst(); B getSecond(); @Override String toString(); @Override int hashCode(); @Override boolean equals(Object o);  }### Answer:
@Test public void testToString() throws Exception { Assert.assertNotNull(Fixture.b.toString()); Assert.assertEquals("ImmutablePair{first=1, second=woot}", Fixture.b.toString()); }