assertThrows(
        IllegalArgumentException.class, () -> mediaType.withParameters("a", ImmutableSet.of("…")));
  }

  @SuppressWarnings("nullness") // test of a bogus call
  public void testWithParametersIterable_nullValue() {
    MediaType mediaType = MediaType.parse("text/plain");
    assertThrows(
        NullPointerException.class,
        () -> mediaType.withParameters("a", Arrays.asList((String) null)));
  }