fail("a call to multiset.setCount() to decrease an element's count should throw");
    } catch (UnsupportedOperationException expected) {
    }
  }

  // Unconditional setCount no-ops.

  private void assertZeroToZero() {
    assertSetCount(e3(), 0);
  }

  private void assertOneToOne() {
    assertSetCount(e0(), 1);
  }

  private void assertThreeToThree() {

      fail("a call to multiset.setCount() to decrease an element's count should throw");
    } catch (UnsupportedOperationException expected) {
    }
  }

  // Unconditional setCount no-ops.

  private void assertZeroToZero() {
    assertSetCount(e3(), 0);
  }

  private void assertOneToOne() {
    assertSetCount(e0(), 1);
  }

  private void assertThreeToThree() {