assertThrows(IllegalArgumentException.class, () -> filteredToModify.addAll(toAdd));

        assertThat(filteredToModify).containsExactlyElementsIn(filtered);
      }
    }

    public void testAddToFilterFiltered() {
      for (List<Integer> contents : SAMPLE_INPUTS) {
        C unfiltered = createUnfiltered(contents);
        C filtered1 = filter(unfiltered, EVEN);
        C filtered2 = filter(filtered1, PRIME_DIGIT);