diff --git a/Tests/ProcessTest.php b/Tests/ProcessTest.php
index 013bca9b..ad44373c 100644
--- a/Tests/ProcessTest.php
+++ b/Tests/ProcessTest.php
@@ -300,7 +300,7 @@ public function testInvalidInput($value)
         $process->setInput($value);
     }
 
-    public function provideInvalidInputValues()
+    public static function provideInvalidInputValues()
     {
         return [
             [[]],
@@ -318,7 +318,7 @@ public function testValidInput($expected, $value)
         $this->assertSame($expected, $process->getInput());
     }
 
-    public function provideInputValues()
+    public static function provideInputValues()
     {
         return [
             [null, null],
@@ -327,7 +327,7 @@ public function provideInputValues()
         ];
     }
 
-    public function chainedCommandsOutputProvider()
+    public static function chainedCommandsOutputProvider()
     {
         if ('\\' === \DIRECTORY_SEPARATOR) {
             return [
@@ -421,7 +421,7 @@ public function testIncrementalOutput($getOutput, $getIncrementalOutput, $uri)
         fclose($h);
     }
 
-    public function provideIncrementalOutput()
+    public static function provideIncrementalOutput()
     {
         return [
             ['getOutput', 'getIncrementalOutput', 'php://stdout'],
@@ -955,7 +955,7 @@ public function testMethodsThatNeedARunningProcess($method)
         $process->{$method}();
     }
 
-    public function provideMethodsThatNeedARunningProcess()
+    public static function provideMethodsThatNeedARunningProcess()
     {
         return [
             ['getOutput'],
@@ -986,7 +986,7 @@ public function testMethodsThatNeedATerminatedProcess($method)
         throw $e;
     }
 
-    public function provideMethodsThatNeedATerminatedProcess()
+    public static function provideMethodsThatNeedATerminatedProcess()
     {
         return [
             ['hasBeenSignaled'],
@@ -1091,7 +1091,7 @@ public function testGetOutputWhileDisabled($fetchMethod)
         $p->{$fetchMethod}();
     }
 
-    public function provideOutputFetchingMethods()
+    public static function provideOutputFetchingMethods()
     {
         return [
             ['getOutput'],
@@ -1128,7 +1128,7 @@ public function testTermSignalTerminatesProcessCleanly()
         $this->assertTrue(true, 'A call to signal() is not expected to cause wait() to throw a RuntimeException');
     }
 
-    public function responsesCodeProvider()
+    public static function responsesCodeProvider()
     {
         return [
             // expected output / getter / code to execute
@@ -1138,7 +1138,7 @@ public function responsesCodeProvider()
         ];
     }
 
-    public function pipesCodeProvider()
+    public static function pipesCodeProvider()
     {
         $variations = [
             'fwrite(STDOUT, $in = file_get_contents(\'php://stdin\')); fwrite(STDERR, $in);',
@@ -1181,7 +1181,7 @@ public function testIncrementalOutputDoesNotRequireAnotherCall($stream, $method)
         $process->stop();
     }
 
-    public function provideVariousIncrementals()
+    public static function provideVariousIncrementals()
     {
         return [
             ['php://stdout', 'getIncrementalOutput'],
@@ -1447,7 +1447,7 @@ public function testRawCommandLine()
         $this->assertSame($expected, str_replace('Standard input code', '-', $p->getOutput()));
     }
 
-    public function provideEscapeArgument()
+    public static function provideEscapeArgument()
     {
         yield ['a"b%c%'];
         yield ['a"b^c^'];