PHP / Github Actions workflows: how to provide secrets in $_ENV

I'm trying to use Encrypted secrets from Github to phpunit.

I created some encrypted Secrets in Github, and I tested that in my workflow file :

- name: Execute tests
  env:
    TWITTER_ACCESS_TOKEN: ${{ secrets.TWITTER_ACCESS_TOKEN }}
    TWITTER_ACCESS_TOKEN_SECRET: ${{ secrets.TWITTER_ACCESS_TOKEN_SECRET }}
    TWITTER_ACCOUNT_ID: ${{ secrets.TWITTER_ACCOUNT_ID }}
    TWITTER_BEARER_TOKEN: ${{ secrets.TWITTER_BEARER_TOKEN }}
    TWITTER_CONSUMER_KEY: ${{ secrets.TWITTER_CONSUMER_KEY }}
    TWITTER_CONSUMER_SECRET: ${{ secrets.TWITTER_CONSUMER_SECRET }}
  run: vendor/bin/phpunit

But in my Test file, a simple var_dump($_ENV) is empty (array(0) { }), and my tests don't work.

What is missing ?

Best regards.

Screenshot from Github: