Context: I'm working on master adding a simple feature. After a few minutes I realize it was not so simple and it should have been better to work into a new branch.

This always happens to me and I have no idea how to switch to another branch and take all these uncommited changes with me leaving the master branch clean. I supposed git stash && git stash branch new_branch would simply accomplish that but this is what I get:

~/test $ git status
# On branch master
nothing to commit (working directory clean)

~/test $ echo "hello!" > testing 

~/test $ git status
# On branch master
# Changed but not updated:
#   (use "git add <file>..." to update what will be committed)
#   (use "git checkout -- <file>..." to discard changes in working directory)
#
#   modified:   testing
#
no changes added to commit (use "git add" and/or "git commit -a")

~/test $ git stash
Saved working directory and index state WIP on master: 4402b8c testing
HEAD is now at 4402b8c testing

~/test $ git status
# On branch master
nothing to commit (working directory clean)

~/test $ git stash branch new_branch
Switched to a new branch 'new_branch'
# On branch new_branch
# Changed but not updated:
#   (use "git add <file>..." to update what will be committed)
#   (use "git checkout -- <file>..." to discard changes in working directory)
#
#   modified:   testing
#
no changes added to commit (use "git add" and/or "git commit -a")
Dropped refs/stash@{0} (db1b9a3391a82d86c9fdd26dab095ba9b820e35b)

~/test $ git s
# On branch new_branch
# Changed but not updated:
#   (use "git add <file>..." to update what will be committed)
#   (use "git checkout -- <file>..." to discard changes in working directory)
#
#   modified:   testing
#
no changes added to commit (use "git add" and/or "git commit -a")

~/test $ git checkout master
M   testing
Switched to branch 'master'

~/test $ git status
# On branch master
# Changed but not updated:
#   (use "git add <file>..." to update what will be committed)
#   (use "git checkout -- <file>..." to discard changes in working directory)
#
#   modified:   testing
#
no changes added to commit (use "git add" and/or "git commit -a")

Do you know if there is any way of accomplishing this?