diff --git a/.github/workflows/php.yml b/.github/workflows/php.yml
index 6cdb272..e312b12 100644
--- a/.github/workflows/php.yml
+++ b/.github/workflows/php.yml
@@ -10,16 +10,36 @@ permissions:
   contents: read
 
 jobs:
-  build:
-
+  tests:
     runs-on: ubuntu-latest
-
+    name: "Tests ${{ matrix.php-version }} deps ${{ matrix.dependency-versions }}"
+    strategy:
+      fail-fast: false
+      matrix:
+        # normal, highest, non-dev installs
+        php-version: [ '8.2', '8.1', '8.0' ]
+        dependency-versions: [ 'highest', 'lowest' ]
+        include:
+#          - php-version: '8.2'
+#            dependency-versions: 'lowest'
+          - php-version: '8.1'
+            dependency-versions: 'lowest'
+          - php-version: '8.0'
+            dependency-versions: 'lowest'
+          - php-version: '8.2'
+            dependency-versions: 'highest'
+          - php-version: '8.1'
+            dependency-versions: 'highest'
+          - php-version: '8.0'
+            dependency-versions: 'highest'
     steps:
     - uses: actions/checkout@v3
 
-#    - name: Validate composer.json and composer.lock
-#      run: composer validate --strict
-
+    - name: "Install PHP"
+      uses: shivammathur/setup-php@v2
+      with:
+        coverage: "xdebug"
+        php-version: "${{ matrix.php-version }}" 
     - name: Cache Composer packages
       id: composer-cache
       uses: actions/cache@v3
@@ -29,8 +49,11 @@ jobs:
         restore-keys: |
           ${{ runner.os }}-php-
 
-    - name: Install dependencies
-      run: composer install --prefer-dist --no-progress
+    - name: "Composer install"
+      uses: "ramsey/composer-install@v2"
+      with:
+        dependency-versions: "${{ matrix.dependency-versions }}"
+        composer-options: "--prefer-dist --no-cache --no-progress"
 
     # Add a test script to composer.json, for instance: "test": "vendor/bin/phpunit"
     # Docs: https://getcomposer.org/doc/articles/scripts.md
diff --git a/composer.json b/composer.json
index b41e3c2..13fdb43 100755
--- a/composer.json
+++ b/composer.json
@@ -32,12 +32,12 @@
         "ergebnis/composer-normalize": "^2.29",
         "friendsofphp/php-cs-fixer": "^3.13",
         "phpstan/phpstan": "^1.9",
-        "phpunit/php-code-coverage": "^9.2",
-        "phpunit/phpunit": "^9.5",
+        "phpunit/php-code-coverage": "^9",
+        "phpunit/phpunit": "^9.6",
         "symfony/expression-language": "^5.4 || ^6",
         "symfony/intl": "^5.4 || ^6",
         "symfony/var-dumper": "^5.4 || ^6",
-        "vimeo/psalm": "^5.2"
+        "vimeo/psalm": "^5.5"
     },
     "suggest": {
         "ext-intl": "You need this PHP extension if you will be using `time_zone` alidator with option `intl_compatible`",
diff --git a/tests/Unit/libraryTest.php b/tests/Unit/LibraryTest.php
similarity index 96%
rename from tests/Unit/libraryTest.php
rename to tests/Unit/LibraryTest.php
index 3f450ad..463f001 100644
--- a/tests/Unit/libraryTest.php
+++ b/tests/Unit/LibraryTest.php
@@ -81,13 +81,13 @@ public function testSerializeEmpty(): void
         $empty = $this->createEmptyDto();
         $json = file_get_contents(__DIR__.'/json_empty.json');
 
-        $this->testSerialize($empty, $json);
+        $this->serializeTest($empty, $json);
     }
 
     public function testSerializeValid(): void
     {
         $json = file_get_contents(__DIR__.'/json_valid.json');
-        $this->testSerialize($this->createValidDto(), $json);
+        $this->serializeTest($this->createValidDto(), $json);
     }
 
     public function testIterableDto(): void
@@ -113,7 +113,7 @@ public function testIterableDto(): void
         $simpleUser[$invalidProperty];
     }
 
-    protected function testSerialize(AbstractDto $dtoTransfer, string $exceptedJson): void
+    private function serializeTest(AbstractDto $dtoTransfer, string $exceptedJson): void
     {
         $serializer = new SerializerFacadeDefault();