@Override
	public void cleanup() {
		if (greenMail != null) {
			greenMail.stop();
		}
	}
Base class for fixtures that interact with a mail server. Uses the {@link GreenMail} library and makes sure it is
properly shut down.

<p>
Creates two server setups, one for sending and one for receiving. Depending on the type of module being tested, one
will be used as the real server and the other will be used to interact with the former, or vice-versa.
</p>

@param <T> the type of this

@author Eric Bottard
spring-xd-test-fixtures/src/main/java/org/springframework/xd/test/fixtures/DisposableMailSupport.java