recurse(level + 1);
      }
    }
  }

  private void compareResultsForThisListOfStimuli() {
    int removes = frequency(asList(stimuli), remove);
    if ((!features.contains(IteratorFeature.SUPPORTS_REMOVE) && removes > 1)
        || (stimuli.length >= 5 && removes > 2)) {
      // removes are the most expensive thing to test, since they often throw exceptions with stack
      // traces, so we test them a bit less aggressively

      assertThat(table.get("foo", 3)).isNull();
      assertThat(table.remove(null, 1)).isNull();
      assertThat(table.remove("foo", null)).isNull();
      assertThat(table.remove(null, null)).isNull();
      assertSize(2);
    } else {
      assertThrows(UnsupportedOperationException.class, () -> table.remove("foo", 3));
      assertEquals((Character) 'c', table.get("foo", 3));
    }
  }

    int initialSize = getList().size();
    assertTrue("remove(present) should return true", getList().remove(duplicate));
    assertTrue(
        "After remove(duplicate), a list should still contain the duplicate element",
        getList().contains(duplicate));
    assertFalse(
        "remove(duplicate) should remove the first instance of the "
            + "duplicate element in the list",

                result.remove("compile");
                result.remove("system");
                result.remove("provided");
            } else if ("runtime".equals(scope)) {
                result.remove("compile");
                result.remove("runtime");
            } else if ("compile+runtime".equals(scope)) {
                result.remove("compile");
                result.remove("system");

    map.remove("a");
    assertFalse(underlying.containsKey("a"));

    Set<String> keys = map.keySet();
    keys.remove("b");
    assertFalse(underlying.containsKey("b"));

    Iterator<String> keyIterator = keys.iterator();
    keyIterator.next();
    keyIterator.remove();
    assertFalse(underlying.containsKey("c"));

    derivedFeatures.remove(CollectionFeature.GENERAL_PURPOSE);
    derivedFeatures.remove(CollectionFeature.SUPPORTS_ADD);
    derivedFeatures.remove(CollectionFeature.ALLOWS_NULL_VALUES);
    derivedFeatures.add(CollectionFeature.REJECTS_DUPLICATES_AT_CREATION);
    if (!derivedFeatures.remove(CollectionFeature.SERIALIZABLE_INCLUDING_VIEWS)) {
      derivedFeatures.remove(CollectionFeature.SERIALIZABLE);
    }

    }

    @Override
    public void remove() {
      checkRemove(canRemove);
      if (totalCount == 1) {
        entryIterator.remove();
      } else {
        /*
         * requireNonNull is safe because canRemove is set to true only after we initialize
         * currentEntry (which we never subsequently clear).
         */
        multiset.remove(requireNonNull(currentEntry).getElement());
      }

    }

    @Override
    public void remove() {
      checkRemove(canRemove);
      if (totalCount == 1) {
        entryIterator.remove();
      } else {
        /*
         * requireNonNull is safe because canRemove is set to true only after we initialize
         * currentEntry (which we never subsequently clear).
         */
        multiset.remove(requireNonNull(currentEntry).getElement());
      }

    assertTrue(getMap().remove(k0(), v0()));
    expectMissing(e0());
  }

  @MapFeature.Require(SUPPORTS_REMOVE)
  public void testRemove_supportedPresentKeyWrongValue() {
    assertFalse(getMap().remove(k0(), v3()));
    expectUnchanged();
  }

  @MapFeature.Require(SUPPORTS_REMOVE)
  public void testRemove_supportedWrongKeyPresentValue() {
    assertFalse(getMap().remove(k3(), v0()));
    expectUnchanged();
  }

    assertTrue(getMap().remove(k0(), v0()));
    expectMissing(e0());
  }

  @MapFeature.Require(SUPPORTS_REMOVE)
  public void testRemove_supportedPresentKeyWrongValue() {
    assertFalse(getMap().remove(k0(), v3()));
    expectUnchanged();
  }

  @MapFeature.Require(SUPPORTS_REMOVE)
  public void testRemove_supportedWrongKeyPresentValue() {
    assertFalse(getMap().remove(k3(), v0()));
    expectUnchanged();
  }