verify(reference.getElements());
      } catch (AssertionError cause) {
        throw new AssertionError("failed with stimuli " + subListCopy(stimuli, i + 1), cause);
      }
    }
  }

  private static List<Object> subListCopy(Object[] source, int size) {
    Object[] copy = new Object[size];
    arraycopy(source, 0, copy, 0, size);
    return asList(copy);
  }

        verify(reference.getElements());
      } catch (AssertionError cause) {
        throw new AssertionError("failed with stimuli " + subListCopy(stimuli, i + 1), cause);
      }
    }
  }

  private static List<Object> subListCopy(Object[] source, int size) {
    Object[] copy = new Object[size];
    arraycopy(source, 0, copy, 0, size);
    return asList(copy);
  }