diff --git a/Tests/ProcessTest.php b/Tests/ProcessTest.php
index 3b0533b7..a639f058 100644
--- a/Tests/ProcessTest.php
+++ b/Tests/ProcessTest.php
@@ -76,7 +76,7 @@ public function testInvalidCommand(Process $process)
         $this->assertSame('\\' === \DIRECTORY_SEPARATOR ? 1 : 127, $process->run());
     }
 
-    public function invalidProcessProvider()
+    public static function invalidProcessProvider(): array
     {
         return [
             [new Process(['invalid'])],