> For the complete documentation index, see [llms.txt](https://circleci.com/docs/llms.txt)

# Phase 5 - Test your installation

Test your air-gapped installation using CircleCI’s Reality Check project.

## 1\. Copy CircleCI Server Reality Check

Copy the [CircleCI Server Reality Check repository](https://github.com/circleci/realitycheck) to your GitHub Enterprise installation in your air-gapped environment.

## 2\. Set up CircleCI Server Reality Check

Set up CircleCI Server Reality Check using the [instructions in the README](https://github.com/circleci/realitycheck#installation).

Make sure to set the `CIRCLE_CLOUD_PROVIDER` environment variable to `other`.

## 3\. Modify Reality Check source code

Replace any references to Docker images in `.circleci/config.yml` with your internal Docker registry.

For example, in your GitHub Enterprise instance, change the following:

`````````
  ...
  artifacts_test_results:
    docker:
      - image: python:3.6.0
`````````

`````````
  ...
  artifacts_test_results:
    docker:
      - image: <your-internal-registry-hostname-and-port>/python:3.6.0
`````````

Leave image values nested under "machine" as is. Only modify Docker image values.

## 4\. Run Reality Check

Run Reality Check by pushing a commit to it in your GitHub Enterprise installation.

the `aws_jobs` and `gcp_jobs` workflows will be cancelled automatically due to the `CIRCLE_CLOUD_PROVIDER` environment variable being set to `other`.