} else {
        assertThrows(UnsupportedOperationException.class, () -> map.remove(keyToRemove));
      }
      assertInvariants(map);
    }
  }

  abstract static class RowMapTests extends MapMapTests {
    RowMapTests(
        boolean allowsNullValues,
        boolean supportsRemove,
        boolean supportsClear,
        boolean supportsIteratorRemove) {