#test #tests #testing

static_test

Attribute macro for writing tests which check that a given condition ALWAYS holds true or that a given code path is ALWAYS unreachable

1 unstable release

0.1.0 Oct 20, 2019

#218 in Testing

MIT/Apache

11KB
194 lines

Build Status

#[static_test]

Documentation

Example

use static_test::static_test;

#[static_test]
fn test_slice_get_will_always_succeed_if_length_is_known( buffer: &[u8] ) -> u8 {
    assume!( buffer.len() == 1 );
    match buffer.get( 0 ) {
        Some( &value ) => value,
        None => static_unreachable!()
    }
}

#[static_test]
fn test_multiplication( value: u8 ) {
    assume!( value == 2 );
    static_assert!( value * 10 == 20 );
}

You can specify arbitrary types as parameters and as the return type of every function you mark as #[static_test]. The bodies of those functions will never actually be executed, however every static_assert! and static_unreachable! will still be indirectly checked.

If the compiler can't prove that every static_assert! will always hold true and that every static_unreachable! will always be unreachable then an error will be generated at link time.

Every function marked as #[static_test] will be turned into a #[test] function.

The assume!, static_assert! and static_unreachable! macros are defined by the procedural macro and are only available inside functions marked as #[static_test].

Caveats

  • This requires at least Rust 1.40.
  • This requires the linker to run, so it will have no effect on cargo check.
  • This will only work when you compile your code with optimizations turned on, as it depends on the optimizer to remove unreachable static_assert!s and static_unreachable!s.
  • If an assertion fails the error message will not be great.

Acknowledgments

This is inspired by the no_panic crate.

License

Licensed under either of

at your option.

Contribution

Unless you explicitly state otherwise, any contribution intentionally submitted for inclusion in the work by you, as defined in the Apache-2.0 license, shall be dual licensed as above, without any additional terms or conditions.

Dependencies

~310–730KB
~18K SLoC