diff --git a/Tests/DocsXsd/DocsXsdTest.php b/Tests/DocsXsd/DocsXsdTest.php
index d978967..5676a1b 100644
--- a/Tests/DocsXsd/DocsXsdTest.php
+++ b/Tests/DocsXsd/DocsXsdTest.php
@@ -60,7 +60,7 @@ public function testXsdValidationPassedWithValidXml($fixtureFile)
      *
      * @return array<string, array<string, string>>
      */
-    public function dataValidXsd()
+    public static function dataValidXsd()
     {
         return [
             'Valid docs example with single standard in the file' => [
@@ -110,7 +110,7 @@ public function testXsdValidationFailsForInvalidXml($fixtureFile, $expectedStdOu
      *
      * @return array<string, array<string, string>>
      */
-    public function dataInvalidXsd()
+    public static function dataInvalidXsd()
     {
         return [
             'Title attribute too long on <documentation> element' => [
diff --git a/Tests/FeatureComplete/Check/ColorTest.php b/Tests/FeatureComplete/Check/ColorTest.php
index c6aba94..1cdbe82 100644
--- a/Tests/FeatureComplete/Check/ColorTest.php
+++ b/Tests/FeatureComplete/Check/ColorTest.php
@@ -65,7 +65,7 @@ public function testColors($fixtureDir, $expectedOutput, $exitCode, $src = 'stdo
      *
      * @return array<string, array<string, string|int>>
      */
-    public function dataColors()
+    public static function dataColors()
     {
         return [
             'feature complete - header' => [
diff --git a/Tests/FeatureComplete/Check/MarkProgressTest.php b/Tests/FeatureComplete/Check/MarkProgressTest.php
index 8801f0d..0bacaeb 100644
--- a/Tests/FeatureComplete/Check/MarkProgressTest.php
+++ b/Tests/FeatureComplete/Check/MarkProgressTest.php
@@ -105,7 +105,7 @@ public function testProgress($nrOfFiles, $expectedOutput)
      *
      * @return array<string, array<string, int|string>>
      */
-    public function dataProgress()
+    public static function dataProgress()
     {
         return [
             'single line progress reporting (<= 60 sniffs)'      => [
diff --git a/Tests/FeatureComplete/Check/NoSniffsTest.php b/Tests/FeatureComplete/Check/NoSniffsTest.php
index d043b20..58abf3d 100644
--- a/Tests/FeatureComplete/Check/NoSniffsTest.php
+++ b/Tests/FeatureComplete/Check/NoSniffsTest.php
@@ -78,7 +78,7 @@ public function testTargetDoesntContainSniffs($fixtureDir)
      *
      * @return array<string, array<string>>
      */
-    public function dataTargetDoesntContainSniffs()
+    public static function dataTargetDoesntContainSniffs()
     {
         return [
             'empty directory'                            => ['EmptyDir'],
diff --git a/Tests/FeatureComplete/Check/ValidStandardsTest.php b/Tests/FeatureComplete/Check/ValidStandardsTest.php
index 82a2417..30f6df7 100644
--- a/Tests/FeatureComplete/Check/ValidStandardsTest.php
+++ b/Tests/FeatureComplete/Check/ValidStandardsTest.php
@@ -63,7 +63,7 @@ public function testFeatureCompleteStandard($fixtureDir, $testDocCount)
      *
      * @return array<string, array<string, string|int>>
      */
-    public function dataFeatureCompleteStandard()
+    public static function dataFeatureCompleteStandard()
     {
         return [
             'feature complete with CSS test files'      => [
diff --git a/Tests/FeatureComplete/Config/GetHelpTest.php b/Tests/FeatureComplete/Config/GetHelpTest.php
index 5f24db3..70ceec3 100644
--- a/Tests/FeatureComplete/Config/GetHelpTest.php
+++ b/Tests/FeatureComplete/Config/GetHelpTest.php
@@ -107,7 +107,7 @@ public function testShowHelpNoColors($command)
      *
      * @return array<string, array<string, string>>
      */
-    public function dataShowHelp()
+    public static function dataShowHelp()
     {
         return [
             '-h'     => [
diff --git a/Tests/FeatureComplete/Config/GetVersionTest.php b/Tests/FeatureComplete/Config/GetVersionTest.php
index 95fc977..36f5502 100644
--- a/Tests/FeatureComplete/Config/GetVersionTest.php
+++ b/Tests/FeatureComplete/Config/GetVersionTest.php
@@ -49,7 +49,7 @@ public function testShowVersion($command)
      *
      * @return array<string, array<string, string>>
      */
-    public function dataShowVersion()
+    public static function dataShowVersion()
     {
         return [
             '-V'        => [
diff --git a/Tests/FeatureComplete/Config/MagicMethodsTest.php b/Tests/FeatureComplete/Config/MagicMethodsTest.php
index 8c16eb6..b062f30 100644
--- a/Tests/FeatureComplete/Config/MagicMethodsTest.php
+++ b/Tests/FeatureComplete/Config/MagicMethodsTest.php
@@ -65,7 +65,7 @@ public function testGet($propertyName, $expected)
      *
      * @return array<string, array<string, string|int|null>>
      */
-    public function dataGet()
+    public static function dataGet()
     {
         return [
             'property which doesn\'t exist on the class' => [
@@ -104,7 +104,7 @@ public function testIsset($propertyName, $expected)
      *
      * @return array<string, array<string, string|bool>>
      */
-    public function dataIsset()
+    public static function dataIsset()
     {
         return [
             'property which doesn\'t exist on the class' => [
@@ -167,7 +167,7 @@ public function testUnset($propertyName)
      *
      * @return array<string, array<string>>
      */
-    public function dataSetUnset()
+    public static function dataSetUnset()
     {
         return [
             'property which doesn\'t exist on the class' => ['doesnotexist'],
diff --git a/Tests/FeatureComplete/Config/ProcessCliCommandTest.php b/Tests/FeatureComplete/Config/ProcessCliCommandTest.php
index 9d22cf0..7593298 100644
--- a/Tests/FeatureComplete/Config/ProcessCliCommandTest.php
+++ b/Tests/FeatureComplete/Config/ProcessCliCommandTest.php
@@ -73,7 +73,7 @@ public function testProcessCliCommandUnsupportedArgument($command)
      *
      * @return array<string, array<string, string>>
      */
-    public function dataProcessCliCommandUnsupportedArgument()
+    public static function dataProcessCliCommandUnsupportedArgument()
     {
         return [
             'Unsupported short arguments' => [
@@ -141,7 +141,7 @@ public function testProcessCliCommand($command, array $expectedChanged, $checkSh
      *
      * @return array<string, array<string, string|bool|array<string, string|bool|int|array<string>>>>
      */
-    public function dataProcessCliCommand()
+    public static function dataProcessCliCommand()
     {
         /*
          * For project root, we only really verify that it has been set as the value will depend
@@ -402,7 +402,7 @@ public function testProcessCliCommandOutputOnlyArgs($command, $expectedChanged)
      *
      * @return array<string, array<string, string|array<string, string|bool>>>
      */
-    public function dataProcessCliCommandOutputOnlyArgs()
+    public static function dataProcessCliCommandOutputOnlyArgs()
     {
         /*
          * For project root, we only verify that it has been set as the value will depend on the