def visitedFiles = []
        def visitedDirectories = []
        def fileVisitor = [visitFile: { visitedFiles << it }, visitDir: { visitedDirectories << it }] as FileVisitor

        when:
        fileTree.visit(fileVisitor)
        rootDir.deleteDir()

        then:
        visitedFiles.size() == 3
        visitedFiles.each {

        TarArchiveEntry entry;
        while (!stopFlag.get() && (entry = tar.getNextEntry()) != null) {
            if (entry.isDirectory()) {
                visitor.visitDir(new DetailsImpl(resource, expandedDir, entry, tar, stopFlag, chmod));
            } else {
                visitor.visitFile(new DetailsImpl(resource, expandedDir, entry, tar, stopFlag, chmod));
            }
        }

        def isReproducibleFileOrder

        TestVisitor(boolean isReproducibleFileOrder) {
            this.isReproducibleFileOrder = isReproducibleFileOrder
        }

        @Override
        void visitDir(FileVisitDetails dirDetails) {
            handleDetails(dirDetails)
        }

        @Override
        void visitFile(FileVisitDetails fileDetails) {
            handleDetails(fileDetails)
        }

        List<TestFile> files = []
        new SingleIncludePatternFileTree(baseDir, includePattern).visit(new FileVisitor() {
            @Override
            void visitDir(FileVisitDetails dirDetails) {
            }

            @Override
            void visitFile(FileVisitDetails fileDetails) {
                files.add(new TestFile(fileDetails.file))
            }
        })

    protected static boolean visitAll(FileSystemMirroringFileTree tree) {
        final MutableBoolean hasContent = new MutableBoolean();
        tree.visit(new FileVisitor() {
            @Override
            public void visitDir(FileVisitDetails dirDetails) {
                dirDetails.getFile();
                hasContent.set(true);
            }

            @Override
            public void visitFile(FileVisitDetails fileDetails) {

        collection.minus(Stub(FileCollection)) is collection
    }

    static class BrokenVisitor implements FileCollectionStructureVisitor, FileVisitor {
        @Override
        void visitDir(FileVisitDetails dirDetails) {
            Assert.fail()
        }

        @Override
        void visitFile(FileVisitDetails fileDetails) {
            Assert.fail()
        }

        @Override