public function testCustomerLogout()
{
$event = $this->getMockBuilder('Magento\\Framework\\Event\\Observer')->disableOriginalConstructor()->getMock();
/** @var $event \Magento\Framework\Event\Observer */
$this->customerSession->expects($this->once())->method('setWishlistItemCount')->with($this->equalTo(0));
$this->assertInstanceOf('Magento\\Wishlist\\Model\\Observer', $this->observer->customerLogout($event));
}