image: ubuntu:18.04 
before_script:
  - npm install
cache:
  paths:
  - node_modules

unit-test:
  tags:
    - test
  image: node:16.16.0
  script:
    - echo "Run unit testing"
    - npm run test
    - echo "Test successfully!"

This is what I wrote in gitlab CI/CD and I got an error said "bash: line 122: npm: command not found." I run a gitlab-runner in docker, and someone please help me. Thank you! (I am really new to the gitlab and docker stuff, and sorry for asking dumb questions......)