@Test
public void testDelTree() throws IOException {

    URL jarURL = getClass().getResource("/testjar.jar");
    File jarFile = new File(jarURL.getFile());
    File tempDir = new File(System.getProperty("java.io.tmpdir") + "/testjar_" + System.currentTimeMillis());
    
    assertFalse("Precondition", tempDir.exists());
    Main.unJar(jarFile, tempDir);
    assertTrue(tempDir.exists());
    
    Main.delTree(tempDir);                
    assertFalse(tempDir.exists());
}