descriptor.setVersion("0.1");
        List<String> errors = new ArrayList<>();
        mavenPluginValidator.validate(plugin, descriptor, errors);
        assertFalse(errors.isEmpty(), "Expected collection to not be empty but was empty");
    }

    @Test
    void testInvalidArtifactId() {
        Artifact plugin = new DefaultArtifact(
                "org.apache.maven.its.plugins",
                "maven-it-plugin",
                "0.1",

     *
     * @return default upgrade options
     */
    public static UpgradeOptions createDefaultOptions() {
        UpgradeOptions options = mock(UpgradeOptions.class);
        when(options.all()).thenReturn(Optional.empty());
        when(options.infer()).thenReturn(Optional.empty());
        when(options.model()).thenReturn(Optional.empty());

            return Optional.of(Boolean.TRUE);
        }
        return Optional.empty();
    }

    @Override
    public Optional<Boolean> yes() {
        if (commandLine.hasOption(CLIManager.YES)) {
            return Optional.of(Boolean.TRUE);
        }
        return Optional.empty();
    }

    @Override
    public Optional<List<String>> goals() {

  }

  public void testEmptiesFirst() {
    Optional<String> empty = Optional.empty();
    Optional<String> abc = Optional.of("abc");
    Optional<String> z = Optional.of("z");

    Comparator<Optional<String>> comparator = emptiesFirst(comparing(String::length));
    testComparator(comparator, empty, z, abc);

    // Just demonstrate that no explicit type parameter is required

// client setting, note this will fail if set to empty when
// constructor initializes.
func DomainNames(domainNames []string) EtcdOption {
	return func(args *CoreDNS) {
		args.domainNames = domainNames
	}
}

// DomainIPs set a list of custom domain IPs, note this will
// fail if set to empty when constructor initializes.
func DomainIPs(domainIPs set.StringSet) EtcdOption {

  public void testConcat() {
    assertThat(Bytes.concat()).isEqualTo(EMPTY);
    assertThat(Bytes.concat(EMPTY)).isEqualTo(EMPTY);
    assertThat(Bytes.concat(EMPTY, EMPTY, EMPTY)).isEqualTo(EMPTY);
    assertThat(Bytes.concat(ARRAY1)).isEqualTo(ARRAY1);
    assertThat(Bytes.concat(ARRAY1)).isNotSameInstanceAs(ARRAY1);
    assertThat(Bytes.concat(EMPTY, ARRAY1, EMPTY)).isEqualTo(ARRAY1);
    assertThat(Bytes.concat(ARRAY1, ARRAY1, ARRAY1))

     *
     * @return The group id of the unresolvable model, can be empty but never {@code null}.
     */
    public String getGroupId() {
        return groupId;
    }

    /**
     * Gets the artifact id of the unresolvable model.
     *
     * @return The artifact id of the unresolvable model, can be empty but never {@code null}.
     */
    public String getArtifactId() {

			expectedErr: errInvalidRuleID,
		},
		{ // Rule with empty ID
			inputXML: `<Rule>
							<ID></ID>
							<Filter><Prefix></Prefix></Filter>
							<Expiration>
								<Days>365</Days>
							</Expiration>
                            <Status>Enabled</Status>
	                    </Rule>`,
			expectedErr: nil,
		},
		{ // Rule with empty status
			inputXML: ` <Rule>

  }

  private static final Map<Integer, Integer> EMPTY = emptyMap();
  private static final Map<Integer, Integer> SINGLETON = singletonMap(1, 2);

  public void testMapDifferenceEmptyEmpty() {
    MapDifference<Integer, Integer> diff = Maps.difference(EMPTY, EMPTY);
    assertTrue(diff.areEqual());
    assertEquals(EMPTY, diff.entriesOnlyOnLeft());
    assertEquals(EMPTY, diff.entriesOnlyOnRight());

     *
     * @return an {@link Optional} containing the boolean value {@code true} if specified, or empty
     */
    Optional<Boolean> force();

    /**
     * Should imply "yes" to all questions.
     *
     * @return an {@link Optional} containing the boolean value {@code true} if specified, or empty
     */
    Optional<Boolean> yes();

    /**
     * Returns the list of encryption goals to be executed.