@Test public void testToImmutableSortedMap_withDuplicateKeys() {

  assertThat(
          BiStream.of(2, "two", 1, "one", 1, "uno")
              .collect(toImmutableSortedMap(naturalOrder(), (a, b) -> b)))
      .containsExactly(1, "uno", 2, "two")
      .inOrder();
}