assertThat(min(1, 2)).isEqualTo(1);
    assertThat(min(2, 1)).isEqualTo(1);
    assertThat(max(1, 2)).isEqualTo(2);
    assertThat(max(2, 1)).isEqualTo(2);
  }

  public void testMinMaxNatural_equalInstances() {
    Foo a = new Foo(1);
    Foo b = new Foo(1);
    assertThat(min(a, b)).isSameInstanceAs(a);
    assertThat(max(a, b)).isSameInstanceAs(a);
  }

  public void testMinMaxComparator() {