given:
        def rootDir = tmpDir.createDir("root")
        def dir = rootDir.createDir("a/b")
        def file = dir.file("c.txt").createFile()
        file << "Hello world"
        def link = rootDir.file("a/d")
        link.createLink(dir)

        when:
        def visited = walkDirForPaths(walkerInstance, rootDir, new PatternSet())

    def "missing symbolic link causes an exception - walker: #walkerInstance.class.simpleName"() {
        given:
        def rootDir = tmpDir.createDir("root")
        def dir = rootDir.createDir("a/b")
        def link = rootDir.file("a/d")
        link.createLink(dir)

        when:
        dir.deleteDir()
        walkDirForPaths(walkerInstance, rootDir, new PatternSet())

        then: