diff --git a/.github/workflows/build.yml b/.github/workflows/build.yml
new file mode 100644
index 0000000..4ee1f20
--- /dev/null
+++ b/.github/workflows/build.yml
@@ -0,0 +1,43 @@
+name: build
+
+on:
+  push:
+    branches:
+      - 'main'
+  pull_request:
+    branches:
+      - 'main'
+
+jobs:
+  test:
+    name: "Test (PHP ${{ matrix.php-versions }}, Neos ${{ matrix.neos-versions }})"
+
+    strategy:
+      fail-fast: false
+      matrix:
+        php-versions: [ '8.2', '8.4' ]
+        neos-versions: [ '8.3', '8.4' ]
+
+    runs-on: ubuntu-latest
+
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v2
+        with:
+          path: ${{ env.FLOW_FOLDER }}
+
+      - name: Setup PHP
+        uses: shivammathur/setup-php@v2
+        with:
+          php-version: ${{ matrix.php-versions }}
+          extensions: mbstring, xml, json, zlib, iconv, intl, pdo_sqlite
+          ini-values: date.timezone="Africa/Tunis", opcache.fast_shutdown=0, apc.enable_cli=on
+
+      - name: Set Neos Version
+        run: composer require neos/neos ^${{ matrix.neos-versions }} --no-progress --no-interaction
+
+      - name: Lint
+        run: composer lint
+
+      - name: Stan
+        run: composer analyse
diff --git a/.gitignore b/.gitignore
index 12dc185..018952d 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,4 +1,10 @@
 **/node_modules/**
 node_modules
 **/lib/
-.yarn
\ No newline at end of file
+.yarn
+
+composer.lock
+Packages
+vendor
+bin
+Build
diff --git a/Classes/Domain/StartDateIsMissing.php b/Classes/Domain/StartDateIsMissing.php
index 43655f2..b6101a0 100644
--- a/Classes/Domain/StartDateIsMissing.php
+++ b/Classes/Domain/StartDateIsMissing.php
@@ -8,7 +8,8 @@ final class StartDateIsMissing extends \InvalidArgumentException
 {
     public static function butWasRequired(string $attemptedValue): self
     {
-        return new self('Start date is missing in value ' . $attemptedValue
+        return new self(
+            'Start date is missing in value ' . $attemptedValue
             . ', must contain a DTSTART: line',
             1746602782
         );
diff --git a/Classes/Infrastructure/CalendarIsMissing.php b/Classes/Infrastructure/CalendarIsMissing.php
index 96181b9..2eec24e 100644
--- a/Classes/Infrastructure/CalendarIsMissing.php
+++ b/Classes/Infrastructure/CalendarIsMissing.php
@@ -10,7 +10,8 @@ final class CalendarIsMissing extends \RuntimeException
 {
     public static function butWasRequired(NodeAggregateIdentifier $eventId): self
     {
-        return new self('Failed to resolve calendar ID for event '
+        return new self(
+            'Failed to resolve calendar ID for event '
             . $eventId . ', one of its ancestors must be a calendar',
             1745919357
         );
diff --git a/Classes/Infrastructure/LocationIsMissing.php b/Classes/Infrastructure/LocationIsMissing.php
index e02dd02..2140c58 100644
--- a/Classes/Infrastructure/LocationIsMissing.php
+++ b/Classes/Infrastructure/LocationIsMissing.php
@@ -10,7 +10,8 @@ final class LocationIsMissing extends \RuntimeException
 {
     public static function butWasRequired(NodeAggregateIdentifier $eventId): self
     {
-        return new self('Failed to resolve location time zone for event '
+        return new self(
+            'Failed to resolve location time zone for event '
             . $eventId . ', one of its ancestors must be a location',
             1746795172
         );
diff --git a/README.md b/README.md
new file mode 100644
index 0000000..e96da78
--- /dev/null
+++ b/README.md
@@ -0,0 +1,41 @@
+# Sitegeist.GroundhogDay
+
+> NodeTypes and PHP Tools for Events including recurrence rules 
+> based on RFC 5545 - iCalendar
+
+The package will calculate all future occurences for the next Year based on the contained nodeType mixins. 
+The PHP class `Sitegeist\GroundhogDay\Domain\EventOccurrenceRepository` can be used to fetch events 
+based on calendar, location and time-period.
+
+## Authors & Sponsors
+
+* Bernhard Schmitt - schmitt@sitegeist.de
+
+_The development and the public-releases of this package is generously sponsored by our employer http://www.sitegeist.de._
+
+## Installation
+
+Sitegeist.GroundhogDay is available via packagist:
+```shell
+composer require sitegeist/groundhogday
+```
+
+## Usage 
+
+### NodeTypes 
+
+- Sitegeist.GroundhogDay:Mixin.Calendar
+- Sitegeist.GroundhogDay:Mixin.Event 
+- Sitegeist.GroundhogDay:Mixin.Location
+
+# to be written
+
+## Contributions
+
+We will gladly accept contributions. Please send us pull requests.
+
+In lieu of a formal styleguide, take care to maintain the existing coding style. Please make sure to contribute [PSR-2](https://github.com/php-fig/fig-standards/blob/master/accepted/PSR-2-coding-style-guide.md) compliant sources.
+
+## License
+
+See [LICENSE.md](./LICENSE.md)
diff --git a/Tests/Unit/Domain/EventOccurrenceSpecificationTest.php b/Tests/Unit/Domain/EventOccurrenceSpecificationTest.php
index 029d59b..8aa0dda 100644
--- a/Tests/Unit/Domain/EventOccurrenceSpecificationTest.php
+++ b/Tests/Unit/Domain/EventOccurrenceSpecificationTest.php
@@ -28,7 +28,7 @@ public function testFromArray(array $array, EventOccurrenceSpecification $expect
     }
 
     /**
-     * @return iterable<int,array{array: array<string,mixed>, expectedSpecification: EventOccurrenceSpecification}>
+     * @return iterable<string, array{array: array<string,mixed>, expectedSpecification: EventOccurrenceSpecification}>
      */
     public static function arrayProvider(): iterable
     {
@@ -115,6 +115,9 @@ public function testResolveDates(
         );
     }
 
+    /**
+     * @return iterable<string, array{subject: EventOccurrenceSpecification, afterDate: ?\DateTimeImmutable, expectedEventDates: EventDates[] }>
+     */
     public static function resolvedDatesProvider(): iterable
     {
         yield 'only startDate, no afterDate' => [
@@ -349,6 +352,10 @@ public static function resolvedDatesProvider(): iterable
 
     private static function createDateTime(string $date): \DateTimeImmutable
     {
-        return \DateTimeImmutable::createFromFormat('Y-m-d H:i:s', $date, new \DateTimeZone('UTC'));
+        $date = \DateTimeImmutable::createFromFormat('Y-m-d H:i:s', $date, new \DateTimeZone('UTC'));
+        if ($date instanceof \DateTimeImmutable) {
+            return $date;
+        }
+        throw new \Exception('invalid date string: "' . $date . '"');
     }
 }
diff --git a/composer.json b/composer.json
index 032532f..0ed9914 100644
--- a/composer.json
+++ b/composer.json
@@ -18,14 +18,15 @@
     },
     "require-dev": {
         "phpunit/phpunit": "^9.5",
-        "phpstan/phpstan": "^2.1",
+        "phpstan/phpstan": "^1.12",
         "neos/buildessentials": "^8.3",
         "mikey179/vfsstream": "^1.6",
         "squizlabs/php_codesniffer": "^3.6"
     },
     "scripts": {
+        "fix": "bin/phpcbf --standard=PSR12 --extensions=php --exclude=Generic.Files.LineLength Classes/ Tests/",
         "lint": "bin/phpcs --standard=PSR12 --extensions=php --exclude=Generic.Files.LineLength Classes/ Tests/",
-        "analyse": "bin/phpstan analyse --level 9 Tests/Unit Classes",
+        "analyse": "bin/phpstan analyse --level 8 Tests/Unit Classes",
         "test:unit": "bin/phpunit -c phpunit.xml --enforce-time-limit --coverage-html Build/Reports/coverage Tests",
         "test:functional": [
             "FLOW_CONTEXT=Testing bin/phpunit --colors --stop-on-failure -c Build/BuildEssentials/PhpUnit/FunctionalTests.xml Tests/Functional"