@Test
public void testGetPreInstallFiles() throws Exception {

    final File file1 = new File("./test1.zip");
    final File file2 = new File("./test2.zip");
    final OakMachine machine = builder().withPreInstallUrl(file1.toURI().toURL(), file2.toURI().toURL()).build();
    assertEquals("expect files", Arrays.asList(file1.getAbsoluteFile(), file2.getAbsoluteFile()),
            machine.getPreInstallFiles());
}