use async_std::{fs, task}; #[test] fn open_file() { task::block_on(async { let non_existing_file = "/ashjudlkahasdasdsikdhajik/asdasdasdasdasdasd/fjuiklashdbflasas"; let res = fs::File::open(non_existing_file).await; match res { Ok(_) => panic!("Found file with random name: We live in a simulation"), Err(e) => assert_eq!( "Could not open `/ashjudlkahasdasdsikdhajik/asdasdasdasdasdasd/fjuiklashdbflasas`", &format!("{}", e) ), } }) }