There's a difference between testing and using. We should test their effectiveness. Hopefully, we will never have to use them, but if the time comes where we have no choice, we can't use a weapon that we have no idea if it will work or not. We can contain the explosions, but what happens when we develop quantum rockets, disintegration lasers, and who knows what? At some point in the future, nuke explosions will seem as big as a dust speck. We should test nuclear weapons, to see their power and what they do, but of course they're a last resort, and we need to know their power if things somewhere get too dangerous.
Yes, we do need to test out the nuclear weapons that we make. This would make it to where we know exactly what is going to happen when we set off one of them in a war against a nation, and will make it to where we can advance them.
We should not continue to test nuclear weapons. The benefits of continued testing are few and the dangers are many. We have already competed enough tests of these weapons for the purpose that they are intended. It is not safe to continue with these tests and they pose a health risk to the general public.
There is no reason to continue testing nuclear weapons. We have done so in the past and have seen the devastating results of nuclear weapons. Doing further tests will make other countries even more angrier and will probably encourage them to get nuclear weapons themselves. On top of that, nuclear weapons will pollute the land with radiation for hundreds of years to come.
We have enough nuclear weapons, and we have an adequate understanding of their capabilities. Additional testing has reached the point of diminishing returns, wherein new tests fail to expand our understanding sufficient to justify the risks of conducting such tests.These risks include damage to wildlife and the environment and political fallout from other nations weary of such tests. It is important that we cease future nuclear tests and focus on other technologies and non-military solutions.
In this day and age, there is no need for nuclear weapons. The stockpile of such weapons need to be disarmed and destroyed. There is no need for further testing. Doing so, whether above or below ground, causes extreme environmental damage. Besides, there is an international treaty outlawing such tests.