Containerizing PHP Unit Tests

Containerized PHP tests run in a repeatable image with selected runtime extensions.

What It Does

Containerized PHP tests run in a repeatable image with selected runtime extensions. The following examples distinguish a normal use case, a boundary case and a practical application.

Requirements and Compatibility

A local Composer project with a compatible PHPUnit version and isolated fixtures or stubs.

The code focuses on the core concept. Production implementation may also need routes, validation, persistence, authorization or deployment tooling.

Example 1: Basic Behavior

A small CLI test-image example; copy only the files necessary for the build.

FROM php:8.4-cli
WORKDIR /app
COPY . /app
CMD ["php", "-v"]

This is a Dockerfile example; use it in its appropriate file or shell, not in the PHP source editor.

Example 2: Another Case

Run the image without privileged containers or production secrets.

docker build -t local-php-tests .
docker run --rm local-php-tests

This is a command-line example; use it in its appropriate file or shell, not in the PHP source editor.

Practical Example: Putting It to Use

Verify required extensions in the container itself.

<?php
$mustHave = ["json", "openssl"];
foreach ($mustHave as $extension) if (!extension_loaded($extension)) throw new RuntimeException($extension);
echo "Runtime OK";

Important Behavior and Edge Cases

Never bake real credentials or uncontrolled dependency versions into test images.

Comparison with Related Functions or Approaches

Common Beginner Mistakes

Key Takeaways

• Containerized PHP tests run in a repeatable image with selected runtime extensions.
• Never bake real credentials or uncontrolled dependency versions into test images.
• A local Dockerfile can mirror the CI runtime.

Before adapting these examples, verify the return values, test the failure paths and confirm that your application meets its security and environment requirements.