I have a bitbucket pipelines yml that I have step for running my test script and a step to run a serverless deploy script. Do I need to npm install at each step or will the first npm install carry through and suffice for each subsequent step. Further than that, what is happening under the hood? I know Docker container is created; does each step just update the container?

```
- step:
        name: Test and Build
        script: 
          - npm install --no-package-lock
          - npm run test
    - step:
        name: Deploy Serverless
        script:
          - npm i serverless -g
          - npm install --no-package-lock
          - npm run deploy

```