I've encountered a problem recently where I had to figure out if some checked out code is up-to-date with the svn repository, without actually running svn update. Unfortunately, svn update doesn't have a dry-run option, so I had to find another solution.
I came up with 2, depending on how detailed the information needs to be, which I'm about to share in this post.
1. If you want exact file and directory names, you can run:
svn status -u
If any files need updating, you will see a * before the file name.
svn status wc M wc/bar.c A + wc/qax.c