anchor.diff:  
   For example `image: "node"` becomes the environment variable `BUILDKITE_PLUGIN_DOCKER_IMAGE="node"`, and `links: [ "db", "redis" ]` becomes the enviroment variables `BUILDKITE_PLUGIN_DOCKER_LINKS_0="db"` and `BUILDKITE_PLUGIN_DOCKER_LINKS_1="redis"`.
   
  -## Testing your new plugin
  +## Testing a plugin
   
  -The [Buildkite CLI](https://github.com/buildkite/cli) can be used to run your pipeline steps locally.
  -  - useful for testing your plugin
  -  - requires `buildkite-agent` locally as well
  +To get started with testing, the [Buildkite CLI](https://github.com/buildkite/cli) can be used to run your pipeline steps and plugins locally.
  +  - useful for testing your plugin during development
  +  - requires `buildkite-agent` locally, see the [Agent installation guides](/docs/agent/v3) for installation instructions
     - run your pipeline with `bk local run`
     - code example
  +For more information about the Buildkite CLI and the other things it can do other than pipelines locally, see the [GitHub readme](https://github.com/buildkite/cli). 
  +
  +Another tool available to help test your plugin is the [Plugin Tester](https://github.com/buildkite-plugins/plugin-tester) Docker image. 
  +  - enables automated testing, which is the best option for ongoing plugin development
  +  - the image includes BATS (bash automated testing system) for writing tests
  +  - to get started with the Plugin Tester, add it to your `docker-compose.yml` file
  +  - The below example test uses the bats-mock library to test the input and output of the plugin
  +  - test code example
  +  - run the test locally with the below command
  +  ```
  +  docker-compose run --rm tests
  +  ``` 
   
   A [linter](https://github.com/buildkite-plugins/buildkite-plugin-linter)  is also available to check your new plugin against the latest best practices.
     - can be run locally, or included in a docker-compose file
  
positive.code:             id: my-org/my-plugin
    ``` 
  
  Another tool available to help test your plugin is the [Plugin Tester](https://github.com/buildkite-plugins/plugin-tester) Docker image. 
    - includes BATS (bash automated testing system) for writing tests
    - write tests in BATS and run them inside the container
    - test code example
  
  ## Tools
  
  The following are some helpful tools when developing plugins:
  
negative.code: # Developing plugins
  
  The best place to get started is the [Buildkite Plugins] repository. You can also find third-party plugins with the [buildkite-plugin tag on GitHub][third party plugins]. This guide will walk through how to write a plugin and how to test your plugin step by step.
  
  ## Writing a plugin
  
  Plugins are essentially a collection of hooks with extra configuration. The agent passes the plugin configuration from the pipeline.yml to the plugin hooks as environment variables.
  
  