Preview an SVN Update
Since "svn update" is a subset of "svn merge" you can use something like:\
svn merge --dry-run -r BASE:HEAD .
The only downside is that 'svn merge' does not quite work like 'svn update' in the sense that you can not run 'svn merge' from outside the workspace. E.g. if I have several workspaces under /tmp/irakli: /tmp/irakli/one and /tmp/irakli/two, I can run:\
cd /tmp/ svn update irakli/one
whereas /tmp is not a workspace. We can not do the same with svn merge.