diff -ru src/Symfony/Component/Messenger/Tests/Handler/ExactlyOneHandlerLocatorTest.php src/Symfony/Component/Messenger/Tests/Handler/ExactlyOneHandlerLocatorTest.php
--- src/Symfony/Component/Messenger/Tests/Handler/ExactlyOneHandlerLocatorTest.php	2021-02-19 17:13:45.303854148 +0000
+++ src/Symfony/Component/Messenger/Tests/Handler/ExactlyOneHandlerLocatorTest.php	2021-02-19 17:13:46.250835700 +0000
@@ -24,12 +24,12 @@
 
 class ExactlyOneHandlerLocatorTest extends TestCase
 {
-    public function testItIsAHandlerLocator(): void
+    public function testItIsAHandlerLocator()
     {
         $this->assertInstanceOf(HandlersLocatorInterface::class, new ExactlyOneHandlerLocator([]));
     }
 
-    public function testItProvidesAHandler(): void
+    public function testItProvidesAHandler()
     {
         $handler1 = $this->createPartialMock(ExactlyOneHandlerLocatorTestCallable::class, ['__invoke']);
         $handler2 = $this->createPartialMock(ExactlyOneHandlerLocatorTestCallable::class, ['__invoke']);
@@ -56,7 +56,7 @@
         ]);
     }
 
-    public function testItThrowsExceptionWhenNoHandlerMatchesMessage(): void
+    public function testItThrowsExceptionWhenNoHandlerMatchesMessage()
     {
         $this->expectException(NoHandlerForMessageException::class);