HandlerAt
BHandler* HandlerAt(int32 index) const;
BMessenger messenger(HandlerAt(i));
BHandler* target = HandlerAt(index);
CPPUNIT_ASSERT(Looper.HandlerAt(0) == &Looper);
CPPUNIT_ASSERT(Looper.HandlerAt(1) == NULL);
CPPUNIT_ASSERT(Looper.HandlerAt(-1) == NULL);
CPPUNIT_ASSERT(Looper.HandlerAt(0) == &Looper);
CPPUNIT_ASSERT(Looper.HandlerAt(1) == &Handler1);
CPPUNIT_ASSERT(Looper.HandlerAt(2) == &Handler2);
CPPUNIT_ASSERT(Looper.HandlerAt(3) == &Handler3);
CPPUNIT_ASSERT(Looper.HandlerAt(0) == &Looper);