How to force successful build if post test fails in CircleCI 1.0

In my circle.yml file I have a post test that runs after the normal tests, and only when you are building master. I am trying to find a way to alert if this post test succeeds or fails, but have the build pass regardless of success or failure. Note that the build should still fail if any of the tests in the normal test suite fail. It is only this post test that I wish to see test failure for, but still have the build succeed.

    - |
      if [ master == $CIRCLE_BRANCH ]; then
        npm run extra-tests