You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: app.rs
    path of file: ./repos/dozer/dozer-core/src/tests
    
    the code of the file until where you have to start completion: use super::run_dag;
use crate::app::{App, AppPipeline, PipelineEntryPoint};
use crate::appsource::{AppSourceManager
    
fn test_apps_source_manager_connection_exists() {
    let mut asm = AppSourceManager::new();
    let _r = asm.add(
        Box::new(NoneSourceFactory {}),
        AppSourceMappings::new(
            "conn1".to_string(),
            vec![("table1".to_string(), 1_u16)].into_iter().collect(),
        ),
    );
    let r = asm.add(
        Box::new(NoneSourceFactory {}),
        AppSourceMappings::new(
            "conn1".to_string(),
            vec![("table2".to_string(), 1_u16)].into_iter().collect(),
        ),
    );
    assert!(r.is_err());
}