diff --git a/.editorconfig b/.editorconfig
index 3ab1269..07f8b1e 100644
--- a/.editorconfig
+++ b/.editorconfig
@@ -2,10 +2,15 @@
 
 root = true
 
-[src/**]
+[**]
 charset = utf-8
 end_of_line = lf
-tab_width = 4
 indent_style = space
 trim_trailing_whitespace = true
 insert_final_newline = true
+
+[{src,tests}/**.php]
+tab_width = 4
+
+[*.{neon,xml,md}]
+tab_width = 4
diff --git a/.gitattributes b/.gitattributes
new file mode 100644
index 0000000..266b762
--- /dev/null
+++ b/.gitattributes
@@ -0,0 +1,43 @@
+# Common settings that generally should always be used with your language specific settings
+
+# Auto detect text files and perform LF normalization
+# http://davidlaing.com/2012/09/19/customise-your-gitattributes-to-become-a-git-ninja/
+# Handle line endings automatically for files detected as text
+# and leave all files detected as binary untouched.
+* text=auto
+
+# Git
+.gitattributes text
+.gitignore text
+.gitconfig text
+.gitmodules text
+
+# source code
+*.php diff=php
+
+*.json text
+*.markdown text
+*.md text
+*.neon.dist text
+*.xml text
+*.xml.dist text
+*README* text
+.editorconfig text
+AUTHORS text
+LICENSE text
+
+# Ignore export
+/.appveyor.yml export-ignore
+/.editorconfig export-ignore
+/.editorconfig export-ignore
+/.gitattributes export-ignore
+/.github export-ignore
+/.gitignore export-ignore
+/.gitignore export-ignore
+/SECURITY.md export-ignore
+/docs export-ignore
+/phpcs.xml.dist export-ignore
+/phpstan.neon.dist export-ignore
+/phpunit.xml.dist export-ignore
+/psalm.xml.dist export-ignore
+/tests export-ignore
diff --git a/.phpunit.cache/test-results b/.phpunit.cache/test-results
new file mode 100644
index 0000000..d568f3c
--- /dev/null
+++ b/.phpunit.cache/test-results
@@ -0,0 +1 @@
+{"version":1,"defects":{"Sept\\OAuth2\\Client\\Test\\UserTest::testCreate":5},"times":{"Sept\\OAuth2\\Client\\Test\\UserTest::testCreate":0.001}}
\ No newline at end of file
diff --git a/composer.json b/composer.json
index 463c9b6..0bab53f 100755
--- a/composer.json
+++ b/composer.json
@@ -21,7 +21,11 @@
         "league/oauth2-client": "^2.0"
     },
     "require-dev": {
-        "phpunit/phpunit": "~10.3"
+        "phpstan/extension-installer": "^1.3",
+        "phpstan/phpdoc-parser": "^1.29",
+        "phpstan/phpstan": "^1.10",
+        "phpstan/phpstan-strict-rules": "^1.5",
+        "phpunit/phpunit": "^11.1"
     },
     "autoload": {
         "psr-4": {
@@ -30,12 +34,25 @@
     },
     "autoload-dev": {
         "psr-4": {
-            "Sept\\OAuth2\\Client\\Test\\": "test/src/"
+            "Sept\\OAuth2\\Client\\Test\\": "tests"
         }
     },
     "extra": {
         "branch-alias": {
             "dev-master": "1.0.x-dev"
         }
+    },
+    "scripts": {
+        "test": [
+            "@phpunit",
+            "@phpstan"
+        ],
+        "phpunit": "vendor/bin/phpunit",
+        "phpstan": "vendor/bin/phpstan"
+    },
+    "config": {
+        "allow-plugins": {
+            "phpstan/extension-installer": true
+        }
     }
 }
diff --git a/phpstan.dist.neon b/phpstan.dist.neon
new file mode 100644
index 0000000..1cd333b
--- /dev/null
+++ b/phpstan.dist.neon
@@ -0,0 +1,5 @@
+parameters:
+    level: 8
+    paths:
+        - src
+        - tests
diff --git a/phpunit.xml b/phpunit.xml
deleted file mode 100755
index 289c3f5..0000000
--- a/phpunit.xml
+++ /dev/null
@@ -1,37 +0,0 @@
-<?xml version="1.0" encoding="UTF-8"?>
-<phpunit backupGlobals="false"
-         backupStaticAttributes="false"
-         bootstrap="vendor/autoload.php"
-         colors="true"
-         convertErrorsToExceptions="true"
-         convertNoticesToExceptions="true"
-         convertWarningsToExceptions="true"
-         processIsolation="false"
-         stopOnFailure="false"
-         syntaxCheck="false"
->
-    <logging>
-        <log type="coverage-html"
-                target="./build/coverage/html"
-                charset="UTF-8"
-                highlight="false"
-                lowUpperBound="35"
-                highLowerBound="70"/>
-          <log type="coverage-clover"
-                target="./build/coverage/log/coverage.xml"/>
-    </logging>
-    <testsuites>
-        <testsuite name="Package Test Suite">
-            <directory suffix=".php">./test/</directory>
-        </testsuite>
-    </testsuites>
-    <filter>
-        <whitelist>
-            <directory suffix=".php">./</directory>
-            <exclude>
-                <directory suffix=".php">./vendor</directory>
-                <directory suffix=".php">./test</directory>
-            </exclude>
-        </whitelist>
-    </filter>
-</phpunit>
\ No newline at end of file
diff --git a/phpunit.xml.dist b/phpunit.xml.dist
new file mode 100755
index 0000000..2b6cf09
--- /dev/null
+++ b/phpunit.xml.dist
@@ -0,0 +1,13 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<phpunit xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="https://schema.phpunit.de/11.1/phpunit.xsd" bootstrap="vendor/autoload.php" executionOrder="depends,defects" beStrictAboutOutputDuringTests="true" failOnRisky="true" failOnWarning="true" colors="true" cacheDirectory=".phpunit.cache" requireCoverageMetadata="true" beStrictAboutCoverageMetadata="true">
+  <testsuites>
+    <testsuite name="Gos Test Suite">
+      <directory suffix=".php">tests</directory>
+    </testsuite>
+  </testsuites>
+  <source>
+    <include>
+      <directory suffix=".php">src</directory>
+    </include>
+  </source>
+</phpunit>
diff --git a/src/Provider/SeptemberFirstProvider.php b/src/Provider/SeptemberFirstProvider.php
index 643f292..618b8fe 100755
--- a/src/Provider/SeptemberFirstProvider.php
+++ b/src/Provider/SeptemberFirstProvider.php
@@ -1,12 +1,9 @@
-<?php
-
-declare(strict_types=1);
+<?php declare(strict_types=1);
 
 namespace Sept\OAuth2\Client\Provider;
 
 use League\OAuth2\Client\Provider\Exception\IdentityProviderException;
 use League\OAuth2\Client\Provider\GenericProvider;
-use League\OAuth2\Client\Provider\ResourceOwnerInterface;
 use League\OAuth2\Client\Token\AccessToken;
 use League\OAuth2\Client\Tool\BearerAuthorizationTrait;
 use Psr\Http\Message\ResponseInterface;
@@ -54,17 +51,20 @@ class SeptemberFirstProvider extends GenericProvider
     const USERINFO_PATH = '/2.0/userinfo';
 
     /**
-     * Undocumented function
+     * Constructor
      *
      * @param mixed[] $options
      * @param object[] $collaborators
      */
     public function __construct(array $options = [], array $collaborators = [])
     {
+        $authBase = $options['authBase'] ?? static::AUTH_BASE;
+        $apiBase  = $options['apiBase']  ?? static::API_BASE;
+
         $defaultOptions = [
-            'urlAuthorize' => static::AUTH_BASE.static::AUTHORIZE_PATH,
-            'urlAccessToken' => static::API_BASE.static::ACCESS_TOKEN_PATH,
-            'urlResourceOwnerDetails' => static::API_BASE.static::USERINFO_PATH,
+            'urlAuthorize' => $authBase.static::AUTHORIZE_PATH,
+            'urlAccessToken' => $apiBase.static::ACCESS_TOKEN_PATH,
+            'urlResourceOwnerDetails' => $apiBase.static::USERINFO_PATH,
             'scopes' => static::SCOPES_DEFAULT,
             'scopeSeparator' => static::SCOPES_SEPARATOR,
         ];
@@ -83,7 +83,7 @@ class SeptemberFirstProvider extends GenericProvider
      */
     protected function checkResponse(ResponseInterface $response, $data): void
     {
-        if (! empty($data['error'])) {
+        if (isset($data['error'])) {
             throw new IdentityProviderException($data['error'].': '.$data['message'], 0, $response);
         }
     }
diff --git a/src/Provider/SeptemberFirstUser.php b/src/Provider/SeptemberFirstUser.php
index 76ca7c6..836e0f0 100755
--- a/src/Provider/SeptemberFirstUser.php
+++ b/src/Provider/SeptemberFirstUser.php
@@ -1,6 +1,4 @@
-<?php
-
-declare(strict_types=1);
+<?php declare(strict_types=1);
 
 namespace Sept\OAuth2\Client\Provider;
 
@@ -155,7 +153,7 @@ class SeptemberFirstUser implements ResourceOwnerInterface
      */
     public function getBirthday(): ?\DateTime
     {
-        return ! empty($this->data['birthday']) ? new \DateTime($this->data['birthday']) : null;
+        return isset($this->data['birthday']) ? new \DateTime($this->data['birthday']) : null;
     }
 
     /**
@@ -168,7 +166,7 @@ class SeptemberFirstUser implements ResourceOwnerInterface
      */
     public function getAvatarUrl(bool $rejectDefaultAvatar = false): ?string
     {
-        return ($rejectDefaultAvatar && $this->isDefaultAvatar()) ? null : $this->getField('avatar');
+        return ($rejectDefaultAvatar && ($this->isDefaultAvatar() ?? false)) ? null : $this->getField('avatar');
     }
 
     /**
@@ -182,7 +180,7 @@ class SeptemberFirstUser implements ResourceOwnerInterface
     public function getAvatarSizeUrl(int $size, int $ratioMultiplier = 1, bool $addVersion = true): ?string
     {
         $ratio = ($ratioMultiplier > 1) ? '@' . $ratioMultiplier . 'x' : '';
-        $url = static::AVATAR_BASE .'/'. $this->getId() . ($size ? '.' : '') . $size . $ratio . '.jpeg';
+        $url = static::AVATAR_BASE .'/'. $this->getId() . (((bool) $size)? '.' : '') . $size . $ratio . '.jpeg';
         return $url . ($addVersion ? $this->getAvatarVersionQuery() : '');
     }
 
@@ -244,7 +242,8 @@ class SeptemberFirstUser implements ResourceOwnerInterface
     public function getAvatarVersionQuery(): string
     {
         $query = '';
-        if ($version = $this->getField('avatar_version')) {
+        $version = $this->getField('avatar_version');
+        if ((bool) $version) {
             $query .= '?v=' . $version;
         }
         return $query;
@@ -321,7 +320,7 @@ class SeptemberFirstUser implements ResourceOwnerInterface
     public function getAddressID(): ?int
     {
         $id = $this->getField('address.id');
-        return $id ? (int) $id : null;
+        return ((bool) $id) ? ((int) $id) : null;
     }
 
     /**
@@ -553,7 +552,7 @@ class SeptemberFirstUser implements ResourceOwnerInterface
      */
     public static function getFieldFromArray(string $key, ?array $array): mixed
     {
-        if (strpos($key, '.')) { // key.subKey.subSubKey
+        if ((bool) strpos($key, '.')) { // key.subKey.subSubKey
             list ($key, $subKey) = explode('.', $key, 2);
             return isset($array[$key]) ? static::getFieldFromArray($subKey, $array[$key]) : null;
         }
diff --git a/tests/UserTest.php b/tests/UserTest.php
new file mode 100644
index 0000000..8f592c1
--- /dev/null
+++ b/tests/UserTest.php
@@ -0,0 +1,22 @@
+<?php declare(strict_types=1);
+
+namespace Sept\OAuth2\Client\Test;
+
+use PHPUnit\Framework\Attributes\CoversMethod;
+use PHPUnit\Framework\TestCase;
+use Sept\OAuth2\Client\Provider\SeptemberFirstUser;
+
+#[CoversMethod(SeptemberFirstUser::class, 'getFirstName')]
+final class UserTest extends TestCase
+{
+    public function testCreate(): void
+    {
+        $name = 'Alex';
+        $user = new SeptemberFirstUser([
+            'personal_name' => [
+                'name' => $name,
+            ],
+        ]);
+        self::assertSame($name, $user->getFirstName());
+    }
+}