[TASK] Make the data providers static (#443)

Newer versions of PHPUnit require this, and we might as well do this
now.

Closes #414

Author: oliverklee

tests/CSSList/AtRuleBlockListTest.php

@@ -46,7 +46,7 @@ public function implementsCommentable()
     /**
      * @return array<string, array<int, string>>
      */
-    public function mediaRuleDataProvider()
+    public static function mediaRuleDataProvider()
     {
         return [
             'without spaces around arguments' => ['@media(min-width: 768px){.class{color:red}}'],

tests/CSSList/DocumentTest.php

@@ -50,7 +50,7 @@ public function getContentsInitiallyReturnsEmptyArray()
     /**
      * @return array<string, array<int, array<int, DeclarationBlock>>>
      */
-    public function contentsDataProvider()
+    public static function contentsDataProvider()
     {
         return [
             'empty array' => [[]],

tests/RuleSet/DeclarationBlockTest.php

@@ -33,7 +33,7 @@ public function expandBorderShorthand($sCss, $sExpected)
     /**
      * @return array<int, array<int, string>>
      */
-    public function expandBorderShorthandProvider()
+    public static function expandBorderShorthandProvider()
     {
         return [
             ['body{ border: 2px solid #000 }', 'body {border-width: 2px;border-style: solid;border-color: #000;}'],
@@ -66,7 +66,7 @@ public function expandFontShorthand($sCss, $sExpected)
     /**
      * @return array<int, array<int, string>>
      */
-    public function expandFontShorthandProvider()
+    public static function expandFontShorthandProvider()
     {
         return [
             [
@@ -122,7 +122,7 @@ public function expandBackgroundShorthand($sCss, $sExpected)
     /**
      * @return array<int, array<int, string>>
      */
-    public function expandBackgroundShorthandProvider()
+    public static function expandBackgroundShorthandProvider()
     {
         return [
             ['body {border: 1px;}', 'body {border: 1px;}'],
@@ -175,7 +175,7 @@ public function expandDimensionsShorthand($sCss, $sExpected)
     /**
      * @return array<int, array<int, string>>
      */
-    public function expandDimensionsShorthandProvider()
+    public static function expandDimensionsShorthandProvider()
     {
         return [
             ['body {border: 1px;}', 'body {border: 1px;}'],
@@ -213,7 +213,7 @@ public function createBorderShorthand($sCss, $sExpected)
     /**
      * @return array<int, array<int, string>>
      */
-    public function createBorderShorthandProvider()
+    public static function createBorderShorthandProvider()
     {
         return [
             ['body {border-width: 2px;border-style: solid;border-color: #000;}', 'body {border: 2px solid #000;}'],
@@ -244,7 +244,7 @@ public function createFontShorthand($sCss, $sExpected)
     /**
      * @return array<int, array<int, string>>
      */
-    public function createFontShorthandProvider()
+    public static function createFontShorthandProvider()
     {
         return [
             ['body {font-size: 12px; font-family: serif}', 'body {font: 12px serif;}'],
@@ -287,7 +287,7 @@ public function createDimensionsShorthand($sCss, $sExpected)
     /**
      * @return array<int, array<int, string>>
      */
-    public function createDimensionsShorthandProvider()
+    public static function createDimensionsShorthandProvider()
     {
         return [
             ['body {border: 1px;}', 'body {border: 1px;}'],
@@ -325,7 +325,7 @@ public function createBackgroundShorthand($sCss, $sExpected)
     /**
      * @return array<int, array<int, string>>
      */
-    public function createBackgroundShorthandProvider()
+    public static function createBackgroundShorthandProvider()
     {
         return [
             ['body {border: 1px;}', 'body {border: 1px;}'],