Mocking singleton without class

gistfile1.coffee

# If I mock markBroken, it's not used in stopApp because the mock wraps module.exports.markBroken but doesn't change the function itself
markBroken = module.exports.markBroken = (app, err) ->
   # does something

module.exports.stopApp = (app) ->
    manager = new AppManager
    manager.stop app, (err, result) ->
        return markBroken app, err if err

# I must do that in order to mock markBroken
module.exports.markBroken = (app, err) ->
   # does something

module.exports.stopApp = (app) ->
    manager = new AppManager
    manager.stop app, (err, result) ->
        return module.exports.markBroken app, err if err