diff --git a/psalm.xml b/psalm.xml
index 5c152d9..e7c5ea3 100644
--- a/psalm.xml
+++ b/psalm.xml
@@ -6,11 +6,13 @@
 >
     <projectFiles>
         <directory name="src" />
+        <directory name="tests" />
     </projectFiles>
 
     <issueHandlers>
         <PossiblyUnusedMethod>
             <errorLevel type="suppress">
+                <directory name="tests" />
                  <referencedMethod name="Erusev\Parsedown\Components\Inlines\PlainText::text" />
                  <referencedMethod name="Erusev\Parsedown\Html\Renderables\Container::contents" />
                  <referencedMethod name="Erusev\Parsedown\Html\Renderables\Element::create" />
@@ -18,14 +20,8 @@
                  <referencedMethod name="Erusev\Parsedown\Html\Renderables\Element::settingName" />
                  <referencedMethod name="Erusev\Parsedown\Html\Renderables\Element::settingAttributes" />
                  <referencedMethod name="Erusev\Parsedown\Html\Renderables\Element::settingContents" />
-                 <referencedMethod name="Erusev\Parsedown\Parsedown::__construct" />
-                 <referencedMethod name="Erusev\Parsedown\Parsedown::text" />
                  <referencedMethod name="Erusev\Parsedown\Parsing\Lines::appendingContext" />
                  <referencedMethod name="Erusev\Parsedown\Parsing\Lines::last" />
-                 <referencedMethod name="Erusev\Parsedown\Configurables\StrictMode::enabled" />
-                 <referencedMethod name="Erusev\Parsedown\Configurables\SafeMode::enabled" />
-                 <referencedMethod name="Erusev\Parsedown\Configurables\BlockTypes::removing" />
-                 <referencedMethod name="Erusev\Parsedown\Configurables\Breaks::enabled" />
                  <referencedMethod name="Erusev\Parsedown\State::mergingWith" />
                  <referencedMethod name="Erusev\Parsedown\Html\Sanitisation\Escaper::htmlElementValue" />
                  <referencedMethod name="Erusev\Parsedown\Configurables\InlineTypes::addingHighPrecedence" />
diff --git a/tests/CommonMarkTest.php b/tests/CommonMarkTest.php
index 1245954..3d3e492 100644
--- a/tests/CommonMarkTest.php
+++ b/tests/CommonMarkTest.php
@@ -25,7 +25,8 @@ namespace Erusev\Parsedown\Tests;
 class CommonMarkTest extends CommonMarkTestStrict
 {
     /**
-     * @return array
+     * @return array<int, array{id: int, section: string, markdown: string, expectedHtml: string}>
+     * @throws \PHPUnit\Framework\AssertionFailedError
      */
     public function data()
     {
@@ -68,10 +69,13 @@ class CommonMarkTest extends CommonMarkTestStrict
     /**
      * @group update
      * @dataProvider dataUpdate
-     * @param $id
-     * @param $section
-     * @param $markdown
-     * @param $expectedHtml
+     * @param int $id
+     * @param string $section
+     * @param string $markdown
+     * @param string $expectedHtml
+     * @return void
+     * @throws \PHPUnit\Framework\AssertionFailedError
+     * @throws \SebastianBergmann\RecursionContext\InvalidArgumentException
      */
     public function testUpdateDatabase($id, $section, $markdown, $expectedHtml)
     {
@@ -79,19 +83,25 @@ class CommonMarkTest extends CommonMarkTestStrict
 
         // you can only get here when the test passes
         $dir = static::getDataDir(true);
-        $basename = $id . '-' . \preg_replace('/[^\w.-]/', '_', $section);
+        $basename = \strval($id) . '-' . \preg_replace('/[^\w.-]/', '_', $section);
         \file_put_contents($dir . $basename . '.md', $markdown);
         \file_put_contents($dir . $basename . '.html', $expectedHtml);
     }
 
     /**
-     * @return array
+     * @return array<int, array{id: int, section: string, markdown: string, expectedHtml: string}>
+     * @throws \PHPUnit\Framework\AssertionFailedError
      */
     public function dataUpdate()
     {
         return parent::data();
     }
 
+    /**
+     * @param bool $mkdir
+     * @return string
+     * @throws \PHPUnit\Framework\AssertionFailedError
+     */
     public static function getDataDir($mkdir = false)
     {
         $dir = __DIR__ . '/commonmark/';
diff --git a/tests/CommonMarkTestStrict.php b/tests/CommonMarkTestStrict.php
index 6687081..f83a058 100644
--- a/tests/CommonMarkTestStrict.php
+++ b/tests/CommonMarkTestStrict.php
@@ -20,30 +20,49 @@ class CommonMarkTestStrict extends TestCase
     const SPEC_LOCAL_CACHE = 'spec_cache.txt';
     const SPEC_CACHE_SECONDS = 300;
 
-    protected $parsedown;
+    /** @var Parsedown */
+    protected $Parsedown;
 
-    protected function setUp()
+    /**
+     * @param string|null $name
+     * @param array $data
+     * @param string $dataName
+     */
+    public function __construct($name = null, array $data = [], $dataName = '')
     {
-        $this->parsedown = new Parsedown(new State([
+        $this->Parsedown = new Parsedown(new State([
             StrictMode::enabled(),
             InlineTypes::initial()->removing([Url::class]),
         ]));
+
+        $this->backupGlobals = false;
+        $this->backupStaticAttributes = false;
+        $this->runTestInSeparateProcess = false;
+
+        parent::__construct($name, $data, $dataName);
     }
 
     /**
      * @dataProvider data
-     * @param $id
-     * @param $section
-     * @param $markdown
-     * @param $expectedHtml
+     * @param int $_
+     * @param string $__
+     * @param string $markdown
+     * @param string $expectedHtml
+     * @return void
+     * @throws \PHPUnit\Framework\AssertionFailedError
+     * @throws \SebastianBergmann\RecursionContext\InvalidArgumentException
      */
-    public function testExample($id, $section, $markdown, $expectedHtml)
+    public function testExample($_, $__, $markdown, $expectedHtml)
     {
-        $actualHtml = $this->parsedown->text($markdown);
+        $actualHtml = $this->Parsedown->text($markdown);
         $this->assertEquals($expectedHtml, $actualHtml);
     }
 
-    public static function getSpec()
+    /**
+     * @return string
+     * @throws \PHPUnit\Framework\AssertionFailedError
+     */
+    public function getSpec()
     {
         $specPath = __DIR__ .'/'.self::SPEC_LOCAL_CACHE;
 
@@ -57,20 +76,23 @@ class CommonMarkTestStrict extends TestCase
             \file_put_contents($specPath, $spec);
         }
 
-        return $spec;
-    }
-
-    /**
-     * @return array
-     */
-    public function data()
-    {
-        $spec = self::getSpec();
         if ($spec === false) {
             $this->fail('Unable to load CommonMark spec from ' . self::SPEC_URL);
         }
 
+        return $spec;
+    }
+
+    /**
+     * @return array<int, array{id: int, section: string, markdown: string, expectedHtml: string}>
+     * @throws \PHPUnit\Framework\AssertionFailedError
+     */
+    public function data()
+    {
+        $spec = $this->getSpec();
+
         $spec = \str_replace("\r\n", "\n", $spec);
+        /** @var string */
         $spec = \strstr($spec, '<!-- END TESTS -->', true);
 
         $matches = [];
@@ -79,6 +101,7 @@ class CommonMarkTestStrict extends TestCase
         $data = [];
         $currentId = 0;
         $currentSection = '';
+        /** @var array{0: string, 1: string, 2?: string, 3?: string} $match */
         foreach ($matches as $match) {
             if (isset($match[3])) {
                 $currentSection = $match[3];
diff --git a/tests/CommonMarkTestWeak.php b/tests/CommonMarkTestWeak.php
index 19832ed..22a4470 100644
--- a/tests/CommonMarkTestWeak.php
+++ b/tests/CommonMarkTestWeak.php
@@ -18,37 +18,57 @@ use Erusev\Parsedown\Html\Renderables\Element;
  */
 class CommonMarkTestWeak extends CommonMarkTestStrict
 {
+    /** @var string */
     protected $textLevelElementRegex;
 
-    protected function setUp()
+    /**
+     * @param string|null $name
+     * @param array $data
+     * @param string $dataName
+     */
+    public function __construct($name = null, array $data = [], $dataName = '')
     {
-        parent::setUp();
-
         $textLevelElements = \array_keys(Element::$TEXT_LEVEL_ELEMENTS);
 
-        \array_walk($textLevelElements, function (&$element) {
-            $element = \preg_quote($element, '/');
-        });
+        \array_walk(
+            $textLevelElements,
+            /**
+             * @param string &$element
+             * @return void
+             */
+            function (&$element) {
+                $element = \preg_quote($element, '/');
+            }
+        );
         $this->textLevelElementRegex = '\b(?:' . \implode('|', $textLevelElements) . ')\b';
+
+        parent::__construct($name, $data, $dataName);
     }
 
     /**
      * @dataProvider data
-     * @param $id
-     * @param $section
-     * @param $markdown
-     * @param $expectedHtml
+     * @param int $_
+     * @param string $__
+     * @param string $markdown
+     * @param string $expectedHtml
+     * @return void
+     * @throws \PHPUnit\Framework\AssertionFailedError
+     * @throws \SebastianBergmann\RecursionContext\InvalidArgumentException
      */
-    public function testExample($id, $section, $markdown, $expectedHtml)
+    public function testExample($_, $__, $markdown, $expectedHtml)
     {
         $expectedHtml = $this->cleanupHtml($expectedHtml);
 
-        $actualHtml = $this->parsedown->text($markdown);
+        $actualHtml = $this->Parsedown->text($markdown);
         $actualHtml = $this->cleanupHtml($actualHtml);
 
         $this->assertEquals($expectedHtml, $actualHtml);
     }
 
+    /**
+     * @param string $markup
+     * @return string
+     */
     protected function cleanupHtml($markup)
     {
         // invisible whitespaces at the beginning and end of block elements
diff --git a/tests/ParsedownTest.php b/tests/ParsedownTest.php
index 187a29f..03bf8aa 100755
--- a/tests/ParsedownTest.php
+++ b/tests/ParsedownTest.php
@@ -15,30 +15,40 @@ use PHPUnit\Framework\TestCase;
 
 class ParsedownTest extends TestCase
 {
+    /**
+     * @param string|null $name
+     * @param array $data
+     * @param string $dataName
+     */
     final public function __construct($name = null, array $data = [], $dataName = '')
     {
         $this->dirs = $this->initDirs();
 
+        $this->backupGlobals = false;
+        $this->backupStaticAttributes = false;
+        $this->runTestInSeparateProcess = false;
+
         parent::__construct($name, $data, $dataName);
     }
 
+    /** @var string[]  */
     private $dirs;
-    protected $Parsedown;
 
     /**
-     * @return array
+     * @return string[]
      */
     protected function initDirs()
     {
-        $dirs []= \dirname(__FILE__).'/data/';
-
-        return $dirs;
+        return [\dirname(__FILE__).'/data/'];
     }
 
     /**
      * @dataProvider data
-     * @param $test
-     * @param $dir
+     * @param string $test
+     * @param string $dir
+     * @return void
+     * @throws \PHPUnit\Framework\ExpectationFailedException
+     * @throws \SebastianBergmann\RecursionContext\InvalidArgumentException
      */
     public function test_($test, $dir)
     {
@@ -60,6 +70,7 @@ class ParsedownTest extends TestCase
         $this->assertEquals($expectedMarkup, $actualMarkup);
     }
 
+    /** @return array<int, array{0:string, 1:string} */
     public function data()
     {
         $data = [];
@@ -93,6 +104,11 @@ class ParsedownTest extends TestCase
         return $data;
     }
 
+    /**
+     * @return void
+     * @throws \PHPUnit\Framework\ExpectationFailedException
+     * @throws \SebastianBergmann\RecursionContext\InvalidArgumentException
+     */
     public function test_no_markup()
     {
         $markdownWithHtml = <<<MARKDOWN_WITH_MARKUP