@Test
@PrepareForTest({Log.class, Os.class})

public void testPoll_success() throws Exception {
    mockStatic(Log.class);
    mockStatic(Os.class);
    when(Os.poll(any(StructPollfd[].class), anyInt())).then(new CountingAnswer(42));
    assertEquals(42, FileHelper.poll(null, 0));
    assertEquals(1, testResult);
}