IdentityHashMap hashMap = new IdentityHashMap();
checkEmptyHashMapAssumptions(hashMap);
assertFalse(hashMap.containsKey(KEY_TEST_CONTAINS_KEY));
hashMap.put(KEY_TEST_CONTAINS_KEY, VALUE_TEST_CONTAINS_KEY);
assertTrue(hashMap.containsKey(KEY_TEST_CONTAINS_KEY));
assertFalse(hashMap.containsKey(VALUE_TEST_CONTAINS_DOES_NOT_EXIST));
assertFalse(hashMap.containsKey(null));
hashMap.put(null, VALUE_TEST_CONTAINS_KEY);
assertTrue(hashMap.containsKey(null));