@Test
public void testOccurenceCount() {

  Assert.assertEquals(3, CharSequences.countIgnoreCase(" aab Aab aaab", "aab"));
  Assert.assertEquals(0, CharSequences.countIgnoreCase("", "aab"));
  Assert.assertEquals(0, CharSequences.countIgnoreCase(" ", "aab"));
  Assert.assertEquals(0, CharSequences.countIgnoreCase(" ", ""));
}