Dockerfile - Container image definition for testing
01_create_image.sh - script for creating container image locally
02_start_container_with_image.sh - script for starting container from created image

Purpose

Provides a reproducible testing environment that allows:

Running the post-installation script without affecting the host system
Real apt installations (isolated in container)
Testing script logic, prompts, and error handling
Validating syntax and tracing execution

Features

The Dockerfile includes:

Ubuntu 22.04 base image
Passwordless sudo for real apt installations
Useful utilities: bash, wget, tar, curl, gnupg, ca-certificates, file, procps, sudo

Usage

Build the test image

Run the prepared shell script to build the image

cd post_installation_script_test
sh 01_create_image.sh

Start a container for testing

Run the prepared shell script start a new container for testing based in the image and remove container after it is stopped. After container is started an interactive session is started into the container.

cd post_installation_script_test
sh 02_start_container_with_image.sh

Test the script file in the running container

After container is started an interactive session was started in the container and the script can be started for testing. If script is changed on the host it just needs to be restarted in the container to reflect the changes. This works because to folder is mounted into the container.

ls -al
sh <scriptName>.sh

Security Notes

The script is mounted read-only (:ro flag) to prevent container from modifying host files
All apt installations are real but isolated in the container
Use --tmpfs /tmp:rw for any temporary writes inside the container
Container is automatically removed after exit (--rm flag)

README.md

Post-Installation Script Testing