def inputDir = file("inputDir").createDir()
        inputDir.createDir("some/empty/sub-directory")
        inputDir.createFile("some/file.txt")

        when:
        execute("taskWithInputs")
        then:
        executedAndNotSkipped(":taskWithInputs")

        when:
        cleanWorkspace()
        inputDir.createDir("some/other/empty/dir")
        execute("taskWithInputs")

        then:

  }

  @SuppressWarnings("DoNotCall")
  public void testEmpty() {
    Iterator<Object> empty = new EmptyAbstractSequentialIterator<>();
    assertFalse(empty.hasNext());
    try {
      empty.next();
      fail();
    } catch (NoSuchElementException expected) {
    }
    try {
      empty.remove();
      fail();
    } catch (UnsupportedOperationException expected) {
    }
  }

	"istio.io/istio/pkg/util/protomarshal"
)

func TestCleanupEmptyMaps(t *testing.T) {
	tc := []struct {
		name  string
		given func() Mapper
		want  func() *matcher.Matcher
	}{
		{
			name: "empty map at depth = 0",
			given: func() Mapper {
				// root (dest port):
				//   <no matches>
				//   fallback (dest ip):
				//     1.2.3.4: chain
				fallback := NewDestinationIP()

		// transiently empty, but if next is non-nil before
		// the pop and the pop fails, then d is permanently
		// empty, which is the only condition under which it's
		// safe to drop d from the chain.
		d2 := d.next.Load()

		if val, ok := d.popTail(); ok {
			return val, ok
		}

		if d2 == nil {
			// This is the only dequeue. It's empty right
			// now, but could be pushed to in the future.

     * from the collection obtained by {@link #getModelIds()}. As a special case, an empty string can be used as the
     * identifier for the super POM.
     *
     * @param modelId The identifier of the model whose active profiles should be retrieved, must not be {@code null}.
     * @return The active profiles of the model or an empty list if the specified model id does
     *         not refer to a known model or has no active profiles.

	return reject
}

// SendEmptyCert force CA server send empty cert chain.
func (s *CAServer) SendEmptyCert() {
	s.faultInjectLock.Lock()
	s.emptyCert = true
	s.faultInjectLock.Unlock()
	caServerLog.Info("force CA server to send empty cert chain")
}

func (s *CAServer) sendEmpty() bool {
	var empty bool
	s.faultInjectLock.Lock()
	empty = s.emptyCert
	s.faultInjectLock.Unlock()
	return empty
}

    /**
     * Adds an element to the property value.
     *
     * <p>
     * When invoked on a property with no value, this method first sets the value
     * of the property to its current convention value, if set, or an empty collection.
     * </p>
     *
     * @param element The element
     */
    @Incubating
    void append(T element);

    /**
     * Adds an element to the property value.
     *

     *
     * TODO: Rename to getInstrumentedSuperTypes();
     */
    Set<String> getSuperTypes(String type);

    boolean isEmpty();

    static InstrumentationTypeRegistry empty() {
        return EMPTY;
    }

    class EmptyInstrumentationTypeRegistry implements InstrumentationTypeRegistry {
        @Override
        public Set<String> getSuperTypes(String type) {

    /**
     * Adds a map entry to the property value.
     *
     * <p>
     * When invoked on a property with no value, this method first sets the value
     * of the property to its current convention value, if set, or an empty map.
     * </p>
     *
     * @param key the key
     * @param value the value
     */
    @Incubating
    void insert(K key, V value);

    /**
     * Adds a map entry to the property value.
     *

                wConfig.setExcludedUrls(getDefaultString("default.config.web.excludedUrls", StringUtil.EMPTY));
                wConfig.setIncludedDocUrls(getDefaultString("default.config.web.includedDocUrls", StringUtil.EMPTY));
                wConfig.setIncludedUrls(getDefaultString("default.config.web.includedUrls", StringUtil.EMPTY));