Questions here don't get put on hold only because they're off topic. Best as I can tell, you are asking an on topic question. They can however be put on hold for a variety of other reasons - being too broad, it being unclear what you're asking, and so on.
I've put your question back on hold myself because to me, and from the comments it seems like to other site members, we're not sure what you're asking.
Note how the similar question you link is somewhere around 20x larger than your question. That's because they take the time to explain what specifically they're trying to do. (That question also went through some close votes, actually - it initially was very short and just said "where do I find playtesters" and so it started to have the same issue you are having.)
We'd like to help you, but to get good answers you should put a little more into the question. What specifically are you trying to accomplish, what is your situation, and so on.
For example, in this case, if your question is really "I have a dice mechanic and I want to test out its probability," then there will be one kind of answer. If it's "I have a full RPG rulesystem and I want people to play it online," then it has another kind of answer. We don't want to guess what your situation is, we'd like you to explain it so we can make good answers.
Just repeating "I want to test online" doesn't make any of us understand what it is you are asking. Take a minute and explain to us what specifically you're envisioning; what part of the game, what kind of test, what you think a result looks like.