@Bean
		public PropertyPlaceholderConfigurer ppc() {
			PropertyPlaceholderConfigurer propertyPlaceholderConfigurer = new PropertyPlaceholderConfigurer();
			Properties props = new Properties();
			props.put("timeField", "null");
			props.put("dateFormat", "yyyy-MM-dd'T'HH:mm:ss.SSS'Z'");
			props.put("computedNameExpression", "'foo'");
			props.put("incrementExpression", "payload");
			propertyPlaceholderConfigurer.setProperties(props);
			return propertyPlaceholderConfigurer;
		}
Tests the aggregate-counter module.

@author Eric Bottard
spring-xd-analytics/src/test/java/org/springframework/xd/analytics/metrics/integration/AggregateCounterTests.java