diff --git a/tests/AbsoluteDateTest.php b/tests/AbsoluteDateTest.php
index ef5aa95..c8ce464 100755
--- a/tests/AbsoluteDateTest.php
+++ b/tests/AbsoluteDateTest.php
@@ -63,7 +63,7 @@ public function testModifyEnforcePattern(string $pattern, bool $patternIsValid):
     /**
      * @return iterable<mixed>
      */
-    public function providerModifyEnforcePattern(): iterable
+    public static function providerModifyEnforcePattern(): iterable
     {
         // Invalid pattern
         yield ['+1 second', false];
@@ -161,7 +161,7 @@ public function testUnserialization(string $serialized): void
     }
 
     /** @return array<string>[] */
-    public function providerSerializedData(): iterable
+    public static function providerSerializedData(): iterable
     {
         yield 'old format' => ['O:32:"AssoConnect\PHPDate\AbsoluteDate":1:{s:4:"date";s:18:"s:10:"2022-01-01";";}'];
         yield 'another old format' => [
diff --git a/tests/LocalizedStringParserTest.php b/tests/LocalizedStringParserTest.php
index 4fac2a6..4322d08 100644
--- a/tests/LocalizedStringParserTest.php
+++ b/tests/LocalizedStringParserTest.php
@@ -17,7 +17,7 @@ public function testCreateFromLocaleWorks(string $formattedDate, string $locale,
     }
 
     /** @return array{string, string, string}[] */
-    public function provideStringsAndLocales(): iterable
+    public static function provideStringsAndLocales(): iterable
     {
         yield ['09/01/2023', 'en_US', '2023-09-01'];
         yield ['9/1/2023', 'en_US', '2023-09-01'];
diff --git a/tests/TimeTravelerTest.php b/tests/TimeTravelerTest.php
index 882135d..559930d 100644
--- a/tests/TimeTravelerTest.php
+++ b/tests/TimeTravelerTest.php
@@ -24,7 +24,7 @@ public function testAddMonth(string $from, string $expected): void
     }
 
     /** @return array{string, string}[] */
-    public function provideAddMonths(): iterable
+    public static function provideAddMonths(): iterable
     {
         yield ['2020-01-01', '2020-02-01'];
         yield ['2020-01-28', '2020-02-28'];
@@ -42,7 +42,7 @@ public function testRemoveMonth(string $from, string $expected): void
     }
 
     /** @return iterable<string, array{string, string}> */
-    public function provideRemoveMonths(): iterable
+    public static function provideRemoveMonths(): iterable
     {
         foreach (
             [
@@ -77,7 +77,7 @@ public function testAddMonthWithReference(string $reference, string $from, strin
     }
 
     /** @return array{string, string, string}[] */
-    public function provideMonthsWithReference(): iterable
+    public static function provideMonthsWithReference(): iterable
     {
         yield ['2020-01-01', '2020-01-01', '2020-02-01'];
         yield ['2020-01-01', '2020-02-01', '2020-03-01'];
@@ -106,7 +106,7 @@ public function testAddMonthWithReferenceWorksYearOverYear(string $referenceAsSt
     }
 
     /** @return array{string, string}[] */
-    public function provideMonthsWithReferenceOverYear(): iterable
+    public static function provideMonthsWithReferenceOverYear(): iterable
     {
         yield ['2020-01-01', '2021-01-01'];
         yield ['2020-01-15', '2021-01-15'];
@@ -124,7 +124,7 @@ public function testAddYear(string $from, string $expected): void
     }
 
     /** @return array{string, string}[] */
-    public function provideYears(): iterable
+    public static function provideYears(): iterable
     {
         yield ['2020-01-01', '2021-01-01'];
         yield ['2020-01-31', '2021-01-31'];