tests: allow to mock final classes

Author: Alcides Ramos

tests/Unit/Providers/FooTest.php

@@ -52,9 +52,11 @@ public static function dataProviderForGetDateTime(): array
     #[Test]
     public function checkMockFinalClass(): void
     {
-        self::assertEquals('pong', (new Foo())->ping());
+        $instance = new Foo();
 
-        $mock = $this->createMock(Foo::class);
+        self::assertEquals('pong', $instance->ping());
+
+        $mock = $this->createMock(get_class($instance));
         $mock->expects(self::once())->method('ping')->willReturn('knock knock');
 
         self::assertEquals('knock knock', $mock->ping());