Rails test a scheduled mail rake task

I have a rake task that is supposed to send a mail every day to users that has their daily field == true. (I already have a mail implementation in my project that is working, it sends a mail at the creation of an account and for password resetting). I'm using Whenever gem

The thing is, since I'm not in production, I don't know how I could test if it works.

Here is my UserMailer :

def daily_mail(user)
    @user = user
    mail to: user.email, subject: "Mail journalier"
end

My rake task :

desc "Send email to users"

task :email_sender => :environment do |_, args|
  User.find_each do |user|
    UserMailer.daily_mail(user).deliver if user.daily == true
  end
end

And my schedule.rb :

every :day, :at => '12pm' do # Use any day of the week or :weekend, :weekday
  rake "email_sender"
end

I did this after looking tutorials :

whenever --update-crontab store (and tried with --set too)

I tried to do a crontab -l and I get this :

# Begin Whenever generated tasks for: store

0 12 * * * /bin/bash -l -c 'cd /Users/Marco/Documents/TBProject && RAILS_ENV=production bundle exec rake email_sender --silent'

# End Whenever generated tasks for: store

# Begin Whenever generated tasks for: /Users/Marco/Documents/TBProject/config/schedule.rb

0 12 * * * /bin/bash -l -c 'cd /Users/Marco/Documents/TBProject && RAILS_ENV=production bundle exec rake email_sender --silent'

# End Whenever generated tasks for: /Users/Marco/Documents/TBProject/config/schedule.rb

Is their a way to test (or to know) if my task will work on production ?