@Override public boolean replace(long key, long oldValue, long newValue) {
        assert oldValue != nullValue : "replace() called with null-sentinel oldValue " + nullValue;
        assert newValue != nullValue : "replace() called with null-sentinel newValue " + nullValue;
        final long valueAddr = hsa.get(key);
        if (valueAddr == NULL_ADDRESS) {
            return false;
        }
        final long actualValue = mem.getLong(valueAddr);
        if (actualValue != oldValue) {
            return false;
        }
        mem.putLong(valueAddr, newValue);
        return true;
    }
@Test(expected = AssertionError.class)
    @RequireAssertEnabled
    public void test_replaceIfEquals_invalidOldValue() {
        map.replace(newKey(), MISSING_VALUE, newValue());
    }