1 use rayon_core::ThreadPoolBuilder; 2 use std::error::Error; 3 4 #[test] double_init_fail()5fn double_init_fail() { 6 let result1 = ThreadPoolBuilder::new().build_global(); 7 assert_eq!(result1.unwrap(), ()); 8 let err = ThreadPoolBuilder::new().build_global().unwrap_err(); 9 assert!(err.source().is_none()); 10 assert_eq!( 11 err.to_string(), 12 "The global thread pool has already been initialized.", 13 ); 14 } 15