public int mode() throws IOException {
        return -1;
    }
@Issue("JENKINS-26810")
    @Test public void mode() throws Exception {
        File f = tmp.newFile();
        VirtualFile vf = VirtualFile.forFile(f);
        FilePath fp = new FilePath(f);
        VirtualFile vfp = VirtualFile.forFilePath(fp);
        assertEquals(modeString(hudson.util.IOUtils.mode(f)), modeString(vf.mode()));
        assertEquals(modeString(hudson.util.IOUtils.mode(f)), modeString(vfp.mode()));
        fp.chmod(0755); // no-op on Windows, but harmless
        assertEquals(modeString(hudson.util.IOUtils.mode(f)), modeString(vf.mode()));
        assertEquals(modeString(hudson.util.IOUtils.mode(f)), modeString(vfp.mode()));
    }