Expression x = parser.parseExpression("attr", new FluentParserContext().evaluate(AttributeMap.class));
Expression y = parser.parseExpression("flowScope.attr", new FluentParserContext()
.evaluate(RequestContext.class));
attributeMapper.addMapping(new DefaultMapping(x, y));
flow.setInputMapper(attributeMapper);
MockRequestControlContext context = new MockRequestControlContext(flow);
LocalAttributeMap sessionInput = new LocalAttributeMap();
sessionInput.put("attr", "foo");
flow.start(context, sessionInput);
assertEquals("foo", context.getFlowScope().get("attr"));
}