MockFileSessionStorage example

    public function __construct(string $savePath = null, string $name = 'MOCKSESSID', MetadataBag $metaBag = null)
    {
        $this->savePath = $savePath;
        $this->name = $name;
        $this->metaBag = $metaBag;
    }

    public function createStorage(?Request $request): SessionStorageInterface
    {
        return new MockFileSessionStorage($this->savePath, $this->name, $this->metaBag);
    }
}

    public function __construct(string $savePath = null, string $name = 'MOCKSESSID', MetadataBag $metaBag = null)
    {
        $this->savePath = $savePath;
        $this->name = $name;
        $this->metaBag = $metaBag;
    }

    public function createStorage(?Request $request): SessionStorageInterface
    {
        return new MockFileSessionStorage($this->savePath, $this->name, $this->metaBag);
    }
}

    public function testSaveWithoutStart()
    {
        $this->expectException(\RuntimeException::class);
        $storage1 = $this->getStorage();
        $storage1->save();
    }

    private function getStorage(): MockFileSessionStorage
    {
        $storage = new MockFileSessionStorage($this->sessionDir);
        $storage->registerBag(new FlashBag());
        $storage->registerBag(new AttributeBag());

        return $storage;
    }
}