Many people, particularly new users, want to try out posting before
actually taking part in discussions. Often the mechanics of getting
messages out is the most difficult part of Usenet. To this end,
many, many users find it necessary to post their tests to "normal"
groups (for example, news.admin or comp.mail.misc). This is
considered a major netiquette faux pas in the Usenet world. There are
a number of groups available, called test groups, that exist solely
for the purpose of trying out a news system, reader, or even new
signature. They include
alt.test
gnu.gnusenet.test
misc.test
some of which will generate auto-magic replies to your posts to
let you know they made it through. There are certain denizens of
Usenet that frequent the test groups to help new users out. They
respond to the posts, often including the article so the poster can
see how it got to the person's site. Also, many regional hierarchies
have test groups, like phl.test in Philadelphia.
By all means, experiment and test---just do it in its proper place.