diff --git a/tests/OutputFormatTest.php b/tests/OutputFormatTest.php
index 4da2ff2d..9e0d4c4e 100644
--- a/tests/OutputFormatTest.php
+++ b/tests/OutputFormatTest.php
@@ -3,6 +3,7 @@
 namespace Sabberworm\CSS\Tests;
 
 use PHPUnit\Framework\TestCase;
+use Sabberworm\CSS\CSSList\Document;
 use Sabberworm\CSS\OutputFormat;
 use Sabberworm\CSS\Parser;
 
@@ -31,8 +32,14 @@ class OutputFormatTest extends TestCase
 
 EOT;
 
+    /**
+     * @var Parser
+     */
     private $oParser;
 
+    /**
+     * @var Document
+     */
     private $oDocument;
 
     protected function setUp()
diff --git a/tests/ParserTest.php b/tests/ParserTest.php
index 27b4cfda..7f624ba9 100644
--- a/tests/ParserTest.php
+++ b/tests/ParserTest.php
@@ -931,12 +931,12 @@ public function missingPropertyValueLenient()
     }
 
     /**
-     * Parse structure for file.
+     * Parses structure for file.
      *
-     * @param string $sFileName Filename.
-     * @param Settings|null $oSettings Settings.
+     * @param string $sFileName
+     * @param Settings|null $oSettings
      *
-     * @return Document Parsed document.
+     * @return Document parsed document
      */
     private function parsedStructureForFile($sFileName, $oSettings = null)
     {
@@ -1005,8 +1005,6 @@ public function lineNumbersParsing()
 
     /**
      * @expectedException \Sabberworm\CSS\Parsing\UnexpectedTokenException
-     * Credit: This test by @sabberworm (from
-     *     https://github.com/sabberworm/PHP-CSS-Parser/pull/105#issuecomment-229643910 )
      *
      * @test
      */
diff --git a/tests/RuleSet/DeclarationBlockTest.php b/tests/RuleSet/DeclarationBlockTest.php
index 0a0e636f..49526952 100644
--- a/tests/RuleSet/DeclarationBlockTest.php
+++ b/tests/RuleSet/DeclarationBlockTest.php
@@ -13,10 +13,13 @@
 class DeclarationBlockTest extends TestCase
 {
     /**
+     * @param string $sCss
+     * @param string $sExpected
+     *
      * @dataProvider expandBorderShorthandProvider
      *
      * @test
-     * */
+     */
     public function expandBorderShorthand($sCss, $sExpected)
     {
         $oParser = new Parser($sCss);
@@ -27,6 +30,9 @@ public function expandBorderShorthand($sCss, $sExpected)
         self::assertSame(trim((string)$oDoc), $sExpected);
     }
 
+    /**
+     * @return array<int, array<int, string>>
+     */
     public function expandBorderShorthandProvider()
     {
         return [
@@ -40,10 +46,13 @@ public function expandBorderShorthandProvider()
     }
 
     /**
+     * @param string $sCss
+     * @param string $sExpected
+     *
      * @dataProvider expandFontShorthandProvider
      *
      * @test
-     * */
+     */
     public function expandFontShorthand($sCss, $sExpected)
     {
         $oParser = new Parser($sCss);
@@ -54,6 +63,9 @@ public function expandFontShorthand($sCss, $sExpected)
         self::assertSame(trim((string)$oDoc), $sExpected);
     }
 
+    /**
+     * @return array<int, array<int, string>>
+     */
     public function expandFontShorthandProvider()
     {
         return [
@@ -90,10 +102,13 @@ public function expandFontShorthandProvider()
     }
 
     /**
+     * @param string $sCss
+     * @param string $sExpected
+     *
      * @dataProvider expandBackgroundShorthandProvider
      *
      * @test
-     * */
+     */
     public function expandBackgroundShorthand($sCss, $sExpected)
     {
         $oParser = new Parser($sCss);
@@ -104,6 +119,9 @@ public function expandBackgroundShorthand($sCss, $sExpected)
         self::assertSame(trim((string)$oDoc), $sExpected);
     }
 
+    /**
+     * @return array<int, array<int, string>>
+     */
     public function expandBackgroundShorthandProvider()
     {
         return [
@@ -137,10 +155,13 @@ public function expandBackgroundShorthandProvider()
     }
 
     /**
+     * @param string $sCss
+     * @param string $sExpected
+     *
      * @dataProvider expandDimensionsShorthandProvider
      *
      * @test
-     * */
+     */
     public function expandDimensionsShorthand($sCss, $sExpected)
     {
         $oParser = new Parser($sCss);
@@ -151,6 +172,9 @@ public function expandDimensionsShorthand($sCss, $sExpected)
         self::assertSame(trim((string)$oDoc), $sExpected);
     }
 
+    /**
+     * @return array<int, array<int, string>>
+     */
     public function expandDimensionsShorthandProvider()
     {
         return [
@@ -169,10 +193,13 @@ public function expandDimensionsShorthandProvider()
     }
 
     /**
+     * @param string $sCss
+     * @param string $sExpected
+     *
      * @dataProvider createBorderShorthandProvider
      *
      * @test
-     * */
+     */
     public function createBorderShorthand($sCss, $sExpected)
     {
         $oParser = new Parser($sCss);
@@ -183,6 +210,9 @@ public function createBorderShorthand($sCss, $sExpected)
         self::assertSame(trim((string)$oDoc), $sExpected);
     }
 
+    /**
+     * @return array<int, array<int, string>>
+     */
     public function createBorderShorthandProvider()
     {
         return [
@@ -194,10 +224,13 @@ public function createBorderShorthandProvider()
     }
 
     /**
+     * @param string $sCss
+     * @param string $sExpected
+     *
      * @dataProvider createFontShorthandProvider
      *
      * @test
-     * */
+     */
     public function createFontShorthand($sCss, $sExpected)
     {
         $oParser = new Parser($sCss);
@@ -208,6 +241,9 @@ public function createFontShorthand($sCss, $sExpected)
         self::assertSame(trim((string)$oDoc), $sExpected);
     }
 
+    /**
+     * @return array<int, array<int, string>>
+     */
     public function createFontShorthandProvider()
     {
         return [
@@ -231,10 +267,13 @@ public function createFontShorthandProvider()
     }
 
     /**
+     * @param string $sCss
+     * @param string $sExpected
+     *
      * @dataProvider createDimensionsShorthandProvider
      *
      * @test
-     * */
+     */
     public function createDimensionsShorthand($sCss, $sExpected)
     {
         $oParser = new Parser($sCss);
@@ -245,6 +284,9 @@ public function createDimensionsShorthand($sCss, $sExpected)
         self::assertSame(trim((string)$oDoc), $sExpected);
     }
 
+    /**
+     * @return array<int, array<int, string>>
+     */
     public function createDimensionsShorthandProvider()
     {
         return [
@@ -263,10 +305,13 @@ public function createDimensionsShorthandProvider()
     }
 
     /**
+     * @param string $sCss
+     * @param string $sExpected
+     *
      * @dataProvider createBackgroundShorthandProvider
      *
      * @test
-     * */
+     */
     public function createBackgroundShorthand($sCss, $sExpected)
     {
         $oParser = new Parser($sCss);
@@ -277,6 +322,9 @@ public function createBackgroundShorthand($sCss, $sExpected)
         self::assertSame(trim((string)$oDoc), $sExpected);
     }
 
+    /**
+     * @return array<int, array<int, string>>
+     */
     public function createBackgroundShorthandProvider()
     {
         return [