#debug #failure #assertions #fail #automatic #information #messages #fancy

yanked arsert

Assertions that provide more sophisticated failure messages

0.0.2 Jan 12, 2019

MIT license

154 lines

Build Status


arsert - assertions that fail very sophisticatedly

This crate allows you to write assertions like you would with a builtin [assert][assert], but when the assertion fails, it outputs diagnostic information about the parameters to the assertion.


Here's a failing assertion:

use arsert::arsert;
let x = 1;
let y: i32 = 2;
arsert!(x >= y.pow(3));

This outputs:

thread 'main' panicked at 'x >= y . pow ( 3 )
x = 1
y . pow ( 3 ) = 8', arsert_failure/src/lib.rs:23:5

Here's a successful one:

use arsert::arsert;
let x = 20 as i64;
arsert!(x <= x.pow(3));

Supported operations

Right now, arsert supports "simple" assertions (very much like assert does), unary assertions (e.g. *foo and !foo), and assertions on binary operations, like ==, >, && and so on.

I'm working on more supported expressions (and maybe, once proc_macros as statements get stabilized, an extension mechanism).

The Name

Sorry for the toilet humor (everybody poops, y'all). Name improvement suggestions gladly accepted, provided the resulting name is terse and meaningful.

License: MIT


~42K SLoC