assertEquals(ImmutableMap.of(6, "z"), diff1.entriesOnlyOnRight());
    assertEquals(ImmutableMap.of(1, "a"), diff1.entriesInCommon());
    assertEquals(
        ImmutableMap.of(
            3, ValueDifferenceImpl.create("c", "f"), 5, ValueDifferenceImpl.create("e", "g")),
        diff1.entriesDiffering());
    assertThat(diff1.toString())
        .isEqualTo(
            "not equal: only on left={2=b, 4=d}: only on right={6=z}: "