Unit Test the FROM URI of a route

I want to unit test a route for which i used the AdviceWith function replaceFromWith("Direct:Start"); with which i unit tested the route. I got success on that.

But the issue is I replaced the FROM URI which is itself very complicated , Given Below :

I want to unit test the FROM URI , i used the weaveByType(ToDefinition.class).selectFirst().replace().to("mock:out");

This replaced the TO URI with MOCK:OUT But i am unable to keep the route in start mode. How can i use the Producer Template or Is there any other method by which i can test this , without making any changes to my CamelContext.xml

Given below is the code :

Public class CamelAdviceWith extends CamelSpringTestSupport{ 


        @Override 
    protected AbstractApplicationContext createApplicationContext() { 
        return new ClassPathXmlApplicationContext("Camelcontext.xml"); 
    } 

    @Override 
    public boolean isUseAdviceWith() { 
        return true; 
    } 

        @Test 
        public void testAdviceWith() throws Exception 
        { 

                context.getRouteDefinition("gsm-inbound").adviceWith(context, new AdviceWithRouteBuilder() { 

                @Override 
                public void configure() throws Exception { 
                weaveByType(ToDefinition.class).selectFirst().replace().to("mock:out"); 
                } 
            }); 

                context.start(); 

//  template.sendBody(?????????????); --- Commented Code, What should i use here.. 

                context.stop(); 
        } 
}