Why is JUnit a compile scope dependency?

[Juan P.]

I was putting together a maven project and imported hadoop-core as a
dependency and noticed that among the jars it brought with it was JUnit 4.5.
Shouldn't it be a test scope dependency? It also happens with JUnit 3.8.1
for the commons-httpclient-3.0.1 dependency it pulls down from the repo.

Cheers,
Juan