How to test a merge without actually merging first

Question

Is there any way of simulating a git merge between two branches, the current working branch and the master, but without making any changes?

I often have

Answer 1

You can use git merge --no-commit to prevent the merge from actually being committed, and if you don't like how the merge works out, just reset to the original head.

If you definitely don't want to finalize the merge, even if it's a fast-forward (and thus has no conflicts, by definition), you could add --no-ff as well.