diff --git a/.composer-require-checker.json b/.composer-require-checker.json
new file mode 100644
index 0000000..8f13040
--- /dev/null
+++ b/.composer-require-checker.json
@@ -0,0 +1,34 @@
+{
+  "symbol-whitelist": [
+    "null",
+    "true",
+    "false",
+    "static",
+    "self",
+    "parent",
+    "array",
+    "string",
+    "int",
+    "float",
+    "bool",
+    "callable",
+    "iterable",
+    "void",
+    "object",
+    "mixed",
+    "never",
+    "PHPStan\\Analyser\\Scope",
+    "PHPStan\\Node\\InClassMethodNode",
+    "PHPStan\\Reflection\\Php\\PhpFunctionFromParserNodeReflection",
+    "PHPStan\\Rules\\Rule",
+    "PHPStan\\Rules\\RuleErrorBuilder"
+  ],
+  "php-core-extensions": [
+    "Core",
+    "standard",
+    "json",
+    "pcre",
+    "SPL"
+  ],
+  "scan-files": []
+}
diff --git a/.github/workflows/actionlint.yml b/.github/workflows/actionlint.yml
new file mode 100644
index 0000000..8eeb07f
--- /dev/null
+++ b/.github/workflows/actionlint.yml
@@ -0,0 +1,21 @@
+name: actionlint
+
+on:
+  push:
+    branches:
+    - main
+  pull_request:
+    branches:
+    - main
+
+jobs:
+  actionlint:
+    name: Lint GitHub Actions workflows
+    runs-on: ubuntu-latest
+
+    steps:
+    - name: Checkout code
+      uses: actions/checkout@v6
+
+    - name: Run actionlint
+      uses: rhysd/actionlint@v1.7.10
diff --git a/.github/workflows/composer-require-checker.yml b/.github/workflows/composer-require-checker.yml
new file mode 100644
index 0000000..cc9646a
--- /dev/null
+++ b/.github/workflows/composer-require-checker.yml
@@ -0,0 +1,40 @@
+name: Composer Require Checker
+
+on:
+  push:
+    branches:
+    - main
+  pull_request:
+    branches:
+    - main
+
+jobs:
+  composer-require-checker:
+    name: Run Composer Require Checker
+    runs-on: ubuntu-latest
+
+    steps:
+    - name: Checkout code
+      uses: actions/checkout@v6
+
+    - name: Setup PHP
+      uses: shivammathur/setup-php@v2
+      with:
+        php-version: '8.2'
+        extensions: json, curl
+        coverage: none
+        tools: composer:v2, composer-require-checker
+
+    - name: Cache Composer dependencies
+      uses: actions/cache@v5
+      with:
+        path: vendor
+        key: ${{ runner.os }}-composer-${{ hashFiles('**/composer.lock') }}
+        restore-keys: |
+          ${{ runner.os }}-composer-
+
+    - name: Install dependencies
+      run: composer install --prefer-dist --no-progress --no-interaction
+
+    - name: Run Composer Require Checker
+      run: composer-require-checker check --config-file=.composer-require-checker.json
diff --git a/.github/workflows/rector.yml b/.github/workflows/rector.yml
new file mode 100644
index 0000000..3aa92c8
--- /dev/null
+++ b/.github/workflows/rector.yml
@@ -0,0 +1,40 @@
+name: Rector
+
+on:
+  push:
+    branches:
+    - main
+  pull_request:
+    branches:
+    - main
+
+jobs:
+  rector:
+    name: Run Rector (dry-run)
+    runs-on: ubuntu-latest
+
+    steps:
+    - name: Checkout code
+      uses: actions/checkout@v6
+
+    - name: Setup PHP
+      uses: shivammathur/setup-php@v2
+      with:
+        php-version: '8.2'
+        extensions: json, curl
+        coverage: none
+        tools: composer:v2
+
+    - name: Cache Composer dependencies
+      uses: actions/cache@v5
+      with:
+        path: vendor
+        key: ${{ runner.os }}-composer-${{ hashFiles('**/composer.lock') }}
+        restore-keys: |
+          ${{ runner.os }}-composer-
+
+    - name: Install dependencies
+      run: composer install --prefer-dist --no-progress --no-interaction
+
+    - name: Run Rector (dry-run)
+      run: composer rector
diff --git a/.github/workflows/tests.yml b/.github/workflows/tests.yml
new file mode 100644
index 0000000..b2d7890
--- /dev/null
+++ b/.github/workflows/tests.yml
@@ -0,0 +1,71 @@
+name: Tests
+
+on:
+  push:
+    branches:
+    - main
+  pull_request:
+    branches:
+    - main
+
+jobs:
+  test:
+    name: PHP ${{ matrix.php-version }} Tests
+    runs-on: ubuntu-latest
+
+    strategy:
+      fail-fast: false
+      matrix:
+        php-version:
+        - '8.2'
+        - '8.3'
+        - '8.4'
+
+    steps:
+    - name: Checkout code
+      uses: actions/checkout@v6
+
+    - name: Setup PHP
+      uses: shivammathur/setup-php@v2
+      with:
+        php-version: ${{ matrix.php-version }}
+        extensions: curl, json, mbstring
+        coverage: xdebug
+        tools: composer:v2
+
+    - name: Get composer cache directory
+      id: composer-cache
+      run: |
+        {
+          printf dir=
+          composer config cache-files-dir
+        } > "$GITHUB_OUTPUT"
+
+    - name: Cache dependencies
+      uses: actions/cache@v5
+      with:
+        path: ${{ steps.composer-cache.outputs.dir }}
+        key: ${{ runner.os }}-composer-${{ hashFiles('**/composer.lock') }}
+        restore-keys: ${{ runner.os }}-composer-
+
+    - name: Install dependencies
+      run: composer install --prefer-dist --no-progress --no-interaction
+
+    - name: Run tests
+      if: matrix.php-version != '8.2'
+      run: composer test
+
+    - name: Run tests with coverage
+      if: matrix.php-version == '8.2'
+      run: |
+        echo "::group::Running PHPUnit with Coverage"
+        vendor/bin/phpunit --coverage-text --coverage-html coverage-report --colors=never
+        echo "::endgroup::"
+
+    - name: Upload coverage report
+      if: matrix.php-version == '8.2'
+      uses: actions/upload-artifact@v4
+      with:
+        name: coverage-report
+        path: coverage-report/
+        retention-days: 14
diff --git a/.gitignore b/.gitignore
index 7b37592..e20c424 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,4 +1,6 @@
 /vendor/
 composer.lock
 .phpunit.result.cache
+.phpunit.cache/
+coverage-report/
 .php-cs-fixer.cache
diff --git a/.pre-commit-config.yaml b/.pre-commit-config.yaml
index 85c0683..5538f5a 100644
--- a/.pre-commit-config.yaml
+++ b/.pre-commit-config.yaml
@@ -8,6 +8,8 @@ repos:
   - id: trailing-whitespace
   - id: end-of-file-fixer
   - id: check-yaml
+    args:
+    - --unsafe
   - id: check-added-large-files
   - id: check-merge-conflict
   - id: check-json
@@ -29,6 +31,11 @@ repos:
     - --autofix
     - --indent=2
 
+- repo: https://github.com/rhysd/actionlint
+  rev: v1.7.10
+  hooks:
+  - id: actionlint
+
 - repo: local
   hooks:
   - id: php-syntax-check
@@ -75,3 +82,11 @@ repos:
     types:
     - php
     pass_filenames: false
+
+  - id: rector
+    name: Rector Code Modernization
+    entry: composer run-script rector-fix
+    language: system
+    types:
+    - php
+    pass_filenames: false
diff --git a/Taskfile.yml b/Taskfile.yml
new file mode 100644
index 0000000..b155aff
--- /dev/null
+++ b/Taskfile.yml
@@ -0,0 +1,86 @@
+# https://taskfile.dev
+# Task runner for code quality checks
+#
+# SEPARATION OF CONCERNS:
+#   Taskfile: Convenience wrappers for common operations
+#   Composer: Core code quality checks (phpcs, phpstan, rector)
+#
+# Installation: https://taskfile.dev/installation/
+#   macOS:   brew install go-task
+#   Linux:   sh -c "$(curl --location https://taskfile.dev/install.sh)" -- -d -b ~/.local/bin
+#
+# Usage:
+#   task --list              # Show all available tasks
+#   task check               # Run all code quality checks
+#   task fix                 # Auto-fix code style issues
+
+version: '3'
+
+tasks:
+  default:
+    desc: Show available tasks
+    cmds:
+    - task --list
+
+  # === Code Quality (delegates to Composer scripts) ===
+
+  check:
+    desc: Run all code quality checks (calls pre-commit run -a)
+    cmds:
+    - pre-commit run -a
+
+  check:phpcs:
+    desc: Run PHP CodeSniffer (calls composer phpcs)
+    cmds:
+    - composer phpcs
+
+  check:phpstan:
+    desc: Run PHPStan (calls composer phpstan)
+    cmds:
+    - composer phpstan
+
+  check:rector:
+    desc: Run Rector dry-run (calls composer rector)
+    cmds:
+    - composer rector
+
+  fix:
+    desc: Auto-fix code style (calls composer fix)
+    cmds:
+    - composer fix
+
+  fix:phpcs:
+    desc: Auto-fix PHP CodeSniffer issues (calls composer phpcbf)
+    cmds:
+    - composer phpcbf
+
+  fix:rector:
+    desc: Apply Rector fixes (calls composer rector-fix)
+    cmds:
+    - composer rector-fix
+
+  # === Testing ===
+
+  test:
+    desc: Run PHPUnit tests
+    cmds:
+    - composer test
+
+  # === Development Helpers ===
+
+  composer:install:
+    desc: Install composer dependencies
+    cmds:
+    - composer install
+    - echo "Composer dependencies installed"
+
+  composer:update:
+    desc: Update composer dependencies
+    cmds:
+    - composer update
+    - echo "Composer dependencies updated"
+
+  lint:
+    desc: Run PHP syntax check
+    cmds:
+    - composer php-lint
diff --git a/composer.json b/composer.json
index f316b50..91af838 100644
--- a/composer.json
+++ b/composer.json
@@ -17,10 +17,13 @@
     ],
     "require": {
         "php": "^8.2",
+        "nikic/php-parser": "^5.0",
         "phpstan/phpstan": "^2.0"
     },
     "require-dev": {
         "ergebnis/composer-normalize": "^2.42",
+        "phpunit/phpunit": "^11.0",
+        "rector/rector": "^2.0",
         "squizlabs/php_codesniffer": "^4.0"
     },
     "autoload": {
@@ -28,6 +31,11 @@
             "OpenCoreEMR\\PHPStan\\": "src/"
         }
     },
+    "autoload-dev": {
+        "psr-4": {
+            "OpenCoreEMR\\PHPStan\\Tests\\": "tests/"
+        }
+    },
     "config": {
         "allow-plugins": {
             "ergebnis/composer-normalize": true
@@ -43,11 +51,19 @@
     "scripts": {
         "check": [
             "@phpcs",
-            "@phpstan"
+            "@phpstan",
+            "@rector"
+        ],
+        "fix": [
+            "@phpcbf",
+            "@rector-fix"
         ],
         "php-lint": "git ls-files -z '*.php' | xargs -0 -n1 php -l",
         "phpcbf": "phpcbf",
         "phpcs": "phpcs",
-        "phpstan": "phpstan analyse -c phpstan.neon src"
+        "phpstan": "phpstan analyse -c phpstan.neon src",
+        "rector": "rector process --dry-run",
+        "rector-fix": "rector process",
+        "test": "phpunit"
     }
 }
diff --git a/phpunit.xml b/phpunit.xml
new file mode 100644
index 0000000..7a76898
--- /dev/null
+++ b/phpunit.xml
@@ -0,0 +1,24 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<phpunit xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+         xsi:noNamespaceSchemaLocation="vendor/phpunit/phpunit/phpunit.xsd"
+         bootstrap="tests/bootstrap.php"
+         colors="true"
+         cacheDirectory=".phpunit.cache"
+         displayDetailsOnTestsThatTriggerWarnings="true"
+         displayDetailsOnTestsThatTriggerDeprecations="true"
+         displayDetailsOnTestsThatTriggerNotices="true"
+         displayDetailsOnTestsThatTriggerErrors="true"
+         stderr="true"
+         beStrictAboutOutputDuringTests="false">
+    <testsuites>
+        <testsuite name="Unit Tests">
+            <directory>tests/Unit</directory>
+        </testsuite>
+    </testsuites>
+
+    <source>
+        <include>
+            <directory>src</directory>
+        </include>
+    </source>
+</phpunit>
diff --git a/rector.php b/rector.php
new file mode 100644
index 0000000..f0c3115
--- /dev/null
+++ b/rector.php
@@ -0,0 +1,37 @@
+<?php
+
+declare(strict_types=1);
+
+use Rector\Caching\ValueObject\Storage\FileCacheStorage;
+use Rector\Config\RectorConfig;
+use Rector\Php80\Rector\Class_\ClassPropertyAssignToConstructorPromotionRector;
+use Rector\ValueObject\PhpVersion;
+
+return RectorConfig::configure()
+    ->withPaths([
+        __DIR__ . '/src',
+    ])
+    ->withCache(
+        cacheClass: FileCacheStorage::class,
+        cacheDirectory: '/tmp/rector'
+    )
+    ->withConfiguredRule(ClassPropertyAssignToConstructorPromotionRector::class, [
+        'allow_model_based_classes' => true,
+        'inline_public' => false,
+        'rename_property' => true,
+    ])
+    ->withParallel(
+        timeoutSeconds: 120,
+        maxNumberOfProcess: 12,
+        jobSize: 12
+    )
+    ->withPhpSets()
+    ->withPhpVersion(PhpVersion::PHP_82)
+    ->withPreparedSets(
+        deadCode: true,
+        codeQuality: true,
+        typeDeclarations: true
+    )
+    ->withSkip([
+        __DIR__ . '/vendor',
+    ]);
diff --git a/src/Rules/Database/ForbiddenClassesRule.php b/src/Rules/Database/ForbiddenClassesRule.php
index d01e16d..76cdc40 100644
--- a/src/Rules/Database/ForbiddenClassesRule.php
+++ b/src/Rules/Database/ForbiddenClassesRule.php
@@ -46,13 +46,13 @@ public function getNodeType(): string
      */
     public function processNode(Node $node, Scope $scope): array
     {
-        return iterator_to_array($this->getErrors($node, $scope));
+        return iterator_to_array($this->getErrors($node));
     }
 
     /**
      * @return \Generator<\PHPStan\Rules\RuleError>
      */
-    private function getErrors(Use_ $node, Scope $scope): \Generator
+    private function getErrors(Use_ $node): \Generator
     {
         foreach ($node->uses as $use) {
             $importedName = $use->name->toString();
diff --git a/src/Rules/Module/ControllersMustReturnResponseRule.php b/src/Rules/Module/ControllersMustReturnResponseRule.php
index e0bba64..8a13969 100644
--- a/src/Rules/Module/ControllersMustReturnResponseRule.php
+++ b/src/Rules/Module/ControllersMustReturnResponseRule.php
@@ -74,7 +74,7 @@ public function processNode(Node $node, Scope $scope): array
 
         // Check if return type is void
         $function = $scope->getFunction();
-        if ($function !== null) {
+        if ($function instanceof \PHPStan\Reflection\Php\PhpFunctionFromParserNodeReflection) {
             $variants = $function->getVariants();
             if (count($variants) > 0) {
                 $returnType = $variants[0]->getReturnType();
diff --git a/src/Rules/Module/NoLegacyResponseMethodsRule.php b/src/Rules/Module/NoLegacyResponseMethodsRule.php
index 7cc90ab..f4cf81e 100644
--- a/src/Rules/Module/NoLegacyResponseMethodsRule.php
+++ b/src/Rules/Module/NoLegacyResponseMethodsRule.php
@@ -41,7 +41,6 @@ public function getNodeType(): string
     }
 
     /**
-     * @param Node $node
      * @return array<\PHPStan\Rules\RuleError>
      */
     public function processNode(Node $node, Scope $scope): array
diff --git a/src/Rules/Testing/NoCoversAnnotationOnClassRule.php b/src/Rules/Testing/NoCoversAnnotationOnClassRule.php
index e990fe0..5e7e99e 100644
--- a/src/Rules/Testing/NoCoversAnnotationOnClassRule.php
+++ b/src/Rules/Testing/NoCoversAnnotationOnClassRule.php
@@ -38,7 +38,7 @@ public function processNode(Node $node, Scope $scope): array
     {
         $docComment = $node->getDocComment();
 
-        if ($docComment === null) {
+        if (!$docComment instanceof \PhpParser\Comment\Doc) {
             return [];
         }
 
diff --git a/tests/Unit/.gitkeep b/tests/Unit/.gitkeep
new file mode 100644
index 0000000..e69de29
diff --git a/tests/bootstrap.php b/tests/bootstrap.php
new file mode 100644
index 0000000..a075e1e
--- /dev/null
+++ b/tests/bootstrap.php
@@ -0,0 +1,5 @@
+<?php
+
+declare(strict_types=1);
+
+require_once __DIR__ . '/../vendor/autoload.php';