With the configuration you posted, the build will not run for any pushes to the ci branch.
What you could do, though, is skip the tests if the branch name is equal to ci. One of the environment variables we populate each build with is $CIRCLE_BRANCH which contains the name of the branch the build is being run for. So you could do something like this in your circle.yml:
test:
override:
- if [[ $CIRCLE_BRANCH != "ci" ]] ; then <test-command> ; fi