public function testAfterUnsubscribeCustomerById() { $subscriber = $this->getMock('\\Magento\\Newsletter\\Model\\Subscriber|\\PHPUnit_Framework_MockObject_MockObject'); $subscriber->expects($this->once())->method('getMageMonkeyId')->willReturn('magemonkey_id'); $subscriber->expects($this->atLeastOnce())->method('save')->willReturnSelf(); $this->plugin->afterUnsubscribeCustomerById($subscriber); }