assertEquals("item1", bean.getItems().get(0));
    }

    @Test
    void testPerformanceWithRepeatedCalls() throws Exception {
        TestBean bean1 = new TestBean();
        TestBean bean2 = new TestBean();
        PlexusConfiguration config = new XmlPlexusConfiguration("test");
        config.setValue("testValue");

        when(evaluator.evaluate("testValue")).thenReturn("testValue");

    }
    // Should overflow without throwing.
    accumulator.addAll(accumulator.snapshot());
    assertThat(accumulator.count()).isLessThan(0L);
  }

  public void testMean() {
    assertThrows(IllegalStateException.class, () -> emptyAccumulator.mean());
    assertThrows(IllegalStateException.class, () -> emptyAccumulatorByAddAllEmptyIterable.mean());