map.put(I1A, I2B);
assertEquals(1, map.size());
assertSame(I2B, map.get(I1A));
assertSame(null, map.get(I1B));
assertEquals(true, map.containsKey(I1A));
assertEquals(false, map.containsKey(I1B));
assertEquals(false, map.containsValue(I2A));
assertEquals(true, map.containsValue(I2B));
map.put(I1B, I2B);
assertEquals(2, map.size());