_messageMock = $this->createPartialMock( \Magento\Framework\Mail\Message::class, ['setBody', 'setMessageType'] ); } public function testSetBodyHtml() { $this->_messageMock->expects($this->once()) ->method('setMessageType') ->with('text/html'); $this->_messageMock->expects($this->once()) ->method('setBody') ->with('body'); $this->_messageMock->setBodyHtml('body'); } public function testSetBodyText() { $this->_messageMock->expects($this->once()) ->method('setMessageType') ->with('text/plain'); $this->_messageMock->expects($this->once()) ->method('setBody') ->with('body'); $this->_messageMock->setBodyText('body'); } }