test: update coding style

Author: kenjis

tests/system/HTTP/SiteURITest.php

@@ -65,7 +65,7 @@ public function provideConstructor(): iterable
         return array_merge($this->provideSetPath(), $this->provideRelativePathWithQueryOrFragment());
     }
 
-    public function provideSetPath(): iterable
+    public static function provideSetPath(): iterable
     {
         return [
             '' => [

tests/system/Helpers/ArrayHelperTest.php

@@ -519,7 +519,7 @@ public function testArrayGroupByExcludeEmpty(array $indexes, array $data, array
         $this->assertSame($expected, $actual, 'array excluding empty not the same');
     }
 
-    public function provideArrayGroupByIncludeEmpty(): iterable
+    public static function provideArrayGroupByIncludeEmpty(): iterable
     {
         yield 'simple group-by test' => [
             ['color'],
@@ -930,7 +930,7 @@ public function provideArrayGroupByIncludeEmpty(): iterable
         ];
     }
 
-    public function provideArrayGroupByExcludeEmpty(): iterable
+    public static function provideArrayGroupByExcludeEmpty(): iterable
     {
         yield 'simple group-by test' => [
             ['color'],

tests/system/View/TableTest.php

@@ -791,7 +791,7 @@ public function testGenerateOrderedColumns(array $heading, array $row, string $e
         $this->assertStringContainsString($expectContainsString, $generated);
     }
 
-    public function orderedColumnUsecases(): iterable
+    public static function orderedColumnUsecases(): iterable
     {
         yield from [
             'reorder example #1' => [