@Test
public void testExtractPackageName() {

  assertEquals("", CommonUtils.extractPackageName(""));
  assertEquals("", CommonUtils.extractPackageName("hello"));
  assertEquals("a", CommonUtils.extractPackageName("a.hello"));
  assertEquals("a.b.c", CommonUtils.extractPackageName("a.b.c.hello"));
  assertEquals("a.b.c", CommonUtils.extractPackageName("a.b.c."));
  assertEquals("", CommonUtils.extractPackageName(".hello"));
}