Adds Docker to allow users to get the project up and running quickly.

CONTRIBUTING.md

@@ -54,3 +54,22 @@ Integration tests:
 ```bash
 composer test:integration
 ```
+
+## Simplified setup using Docker
+
+If you have Docker installed, you can quickly get all dependencies for Pest in place using
+our Docker files. Assuming you have the repository cloned, you may run the following
+commands:
+
+1. `docker compose build` to build the Docker image
+2. `docker compose run --rm composer install` to install Composer dependencies
+3. `docker compose run --rm composer test` to run the project tests and analysis tools
+
+If you want to check things work against a specific version of PHP, you may include
+the `PHP` build argument when building the image:
+
+```bash
+docker compose build --build-arg PHP=8.2
+```
+
+The default PHP version will always be the lowest version of PHP supported by Pest.

docker-compose.yml

@@ -0,0 +1,14 @@
+version: "3.8"
+
+services:
+  php:
+    build:
+      context: ./docker
+    volumes:
+      - .:/var/www/html
+  composer:
+    build:
+      context: ./docker
+    volumes:
+      - .:/var/www/html
+    entrypoint: ["composer"]

docker/Dockerfile

@@ -0,0 +1,19 @@
+ARG PHP=8.1
+FROM php:${PHP}-cli-alpine
+
+RUN apk update \
+    && apk add zip libzip-dev icu-dev
+
+RUN docker-php-ext-configure zip
+RUN docker-php-ext-install zip
+RUN docker-php-ext-enable zip
+
+RUN docker-php-ext-configure intl
+RUN docker-php-ext-install intl
+RUN docker-php-ext-enable intl
+
+COPY --from=composer:2 /usr/bin/composer /usr/bin/composer
+
+WORKDIR /var/www/html
+
+ENTRYPOINT ["php"]