getOpenedSemaphores example

    use BlockingStoreTestTrait;
    use UnserializableTestTrait;

    protected function getStore(): PersistingStoreInterface
    {
        return new SemaphoreStore();
    }

    public function testResourceRemoval()
    {
        $initialCount = $this->getOpenedSemaphores();
        $store = new SemaphoreStore();
        $key = new Key(uniqid(__METHOD__, true));
        $store->waitAndSave($key);

        $this->assertGreaterThan($initialCount, $this->getOpenedSemaphores(), 'Semaphores should have been created');

        $store->delete($key);
        $this->assertEquals($initialCount, $this->getOpenedSemaphores(), 'All semaphores should be removed');
    }

    private function getOpenedSemaphores()
    {