[FEATURE] Collect code coverage and add a coverage badge (#1160)

Fixes #1126
Fixes #807

.github/workflows/codecoverage.yml

@@ -0,0 +1,72 @@
+# https://help.github.com/en/categories/automating-your-workflow-with-github-actions
+
+on:
+  push:
+    branches:
+      - main
+  pull_request:
+
+name: Code coverage
+
+jobs:
+  code-coverage:
+    name: Code coverage
+
+    runs-on: ubuntu-22.04
+
+    strategy:
+      fail-fast: false
+      matrix:
+        php-version:
+          - '8.3'
+        dependencies:
+          - highest
+
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+
+      - name: Install PHP
+        uses: shivammathur/setup-php@v2
+        with:
+          php-version: ${{ matrix.php-version }}
+          ini-file: development
+          tools: composer:v2
+          coverage: xdebug
+
+      - name: Show the Composer version
+        run: composer --version
+
+      - name: Show the Composer configuration
+        run: composer config --global --list
+
+      - name: Cache dependencies installed with composer
+        uses: actions/cache@v4
+        with:
+          path: ~/.cache/composer
+          key: php${{ matrix.php-version }}-${{ matrix.dependencies }}-composer-${{ hashFiles('**/composer.json') }}
+          restore-keys: |
+            php${{ matrix.php-version }}-${{ matrix.dependencies }}-composer-
+
+      - name: Install Composer dependencies
+        run: |
+          if [[ "${{ matrix.dependencies }}" == 'lowest' ]]; then
+            DEPENDENCIES='--prefer-lowest';
+          else
+            DEPENDENCIES='';
+          fi;
+          composer install --no-progress;
+          composer update --with-dependencies --no-progress "${DEPENDENCIES}";
+          composer show;
+
+      - name: Run Tests
+        run: composer ci:tests:coverage
+
+      - name: Show generated coverage files
+        run: ls -lah
+
+      - name: Upload coverage results to Coveralls
+        uses: coverallsapp/github-action@v2
+        env:
+          github-token: ${{ secrets.GITHUB_TOKEN }}
+          file: coverage.xml

.gitignore

@@ -23,6 +23,7 @@ nbproject
 /.php_cs.cache
 /.php-cs-fixer.cache
 /.phpunit.result.cache
+/coverage.xml
 /vendor/
 composer.lock
 /.phive

README.md

@@ -4,6 +4,7 @@
 [![Latest Stable Version](https://poser.pugx.org/pelago/emogrifier/v/stable.svg)](https://packagist.org/packages/pelago/emogrifier)
 [![Total Downloads](https://poser.pugx.org/pelago/emogrifier/downloads.svg)](https://packagist.org/packages/pelago/emogrifier)
 [![License](https://poser.pugx.org/pelago/emogrifier/license.svg)](https://packagist.org/packages/pelago/emogrifier)
+[![Coverage Status](https://coveralls.io/repos/github/MyIntervals/emogrifier/badge.svg?branch=main)](https://coveralls.io/github/MyIntervals/emogrifier?branch=main)
 
 _n. e•mog•ri•fi•er [\ē-'mä-grƏ-,fī-Ər\] - a utility for changing completely the
 nature or appearance of HTML email, esp. in a particularly fantastic or bizarre

composer.json

@@ -100,6 +100,7 @@
         "ci:tests": [
             "@ci:tests:unit"
         ],
+        "ci:tests:coverage": "phpunit --do-not-cache-result --coverage-clover=coverage.xml",
         "ci:tests:sof": "phpunit --stop-on-failure --do-not-cache-result",
         "ci:tests:unit": "phpunit --do-not-cache-result",
         "composer:normalize": "\"./.phive/composer-normalize\" --no-check-lock",
@@ -117,6 +118,7 @@
         "ci:php:stan": "Checks the PHP types using PHPStan.",
         "ci:static": "Runs all static code analysis checks for the code and the composer.json.",
         "ci:tests": "Runs all dynamic tests (i.e., currently, the unit tests).",
+        "ci:tests:coverage": "Runs the unit tests with code coverage.",
         "ci:tests:sof": "Runs the unit tests and stops at the first failure.",
         "ci:tests:unit": "Runs all unit tests.",
         "composer:normalize": "Reformats and sorts the composer.json file.",