public void initializer() {
		if (!initialized) {
			adminServer = xdEnvironment.getAdminServerUrl();
			validation.verifyXDAdminReady(adminServer);
			containers = getAvailableContainers(adminServer);
			containerResolver = new ContainerResolver(adminServer, containers, STREAM_NAME);
			sources.setContainerResolver(containerResolver);
			sinks.setContainerResolver(containerResolver);
			assertTrue("There must be at least one container", containers.size() > 0);
			initialized = true;
		}
	}
Initializes the environment before the test. Also asserts that the admin server is up and at least one container is
available.
spring-xd-integration-test/src/test/java/org/springframework/xd/integration/test/AbstractIntegrationTest.java