mod laziness {
    struct Panicking;

    impl Iterator for Panicking {
        type Item = ();
        fn next(&mut self) -> Option<()> {
            panic!("iterator adaptor is not lazy")
        }
    }
    
    macro_rules! tests {
        ($(test $name:ident { $body:expr })*) => {
            $(
                #[deny(unused_must_use)]
                #[test]
                fn $name() {
                    let _ = $body;
                }
            )*
        }
    }
    
    use itertools::*;
    
    tests! {
        test interleave {
            Panicking.interleave(Panicking)
        }
        
        test interleave_shortest {
            Panicking.interleave_shortest(Panicking)
        }
        
        test intersperse {
            Panicking.intersperse(())
        }
        
        /* and so on */
    }
}