payload.setHeader(MailProperties.SENT_DATE_PROPERTY, invalid);
payload.setSubject(TEST_SUBJECT);
payload.setHeader(MailProperties.CONTENT_TYPE_PROPERTY, invalid);
payload.setHeader(customProperty, customProperty);
MuleMessageFactory factory = createMuleMessageFactory();
MuleMessage muleMessage = factory.create(payload, encoding, muleContext);
assertEquals(TEST_TO, muleMessage.getInboundProperty(MailProperties.TO_ADDRESSES_PROPERTY));
assertEquals(TEST_CC, muleMessage.getInboundProperty(MailProperties.CC_ADDRESSES_PROPERTY));
assertEquals(TEST_BCC, muleMessage.getInboundProperty(MailProperties.BCC_ADDRESSES_PROPERTY));
assertEquals(TEST_FROM, muleMessage.getInboundProperty(MailProperties.FROM_ADDRESS_PROPERTY));