}

  public void testParse_weakKeysCannotHaveValue() {
    assertThrows(IllegalArgumentException.class, () -> parse("weakKeys=true"));
  }

  public void testParse_repeatedKeyStrength() {
    assertThrows(IllegalArgumentException.class, () -> parse("weakKeys, weakKeys"));
  }

  public void testParse_softValues() {
    CacheBuilderSpec spec = parse("softValues");