Pretty Assertions
When writing tests in Rust, you'll probably use assert_eq!(a, b)
a lot.
If such a test fails, it will present all the details of a
and b
, but you have to spot, the differences yourself, which is not always straightforward, like here:
Wouldn't that task be much easier with a colorful diff?
Yep — and you only need one line of code to make it happen:
extern crate pretty_assertions;
// 1. add the `pretty_assertions` dependency to `Cargo.toml`.
// 2. insert this line at the top of your crate root or integration test
extern crate pretty_assertions;
Tip
Specify it as [dev-dependency]
and it will only be used for compiling tests, examples, and benchmarks.
This way the compile time of cargo build
won't be affected!
In your crate root, also add #[cfg(test)]
to the crate import, like this:
// <-- not needed in examples + integration tests
extern crate pretty_assertions;
Note
- Each example and integration test also needs
#[macro_use] extern crate pretty_assertions
, if you want colorful diffs there. - The replacement is only effective in your own crate, not in other libraries you include.
pretty_assertions
is an ultra-thin wrapper around thedifference
crate, which does the heavy lifting. All thatpretty_assertions
does is to replace theassert_eq!
macro with just about 22 lines of code.
License
Licensed under either of
- Apache License, Version 2.0, (LICENSE-APACHE or http://www.apache.org/licenses/LICENSE-2.0)
- MIT license (LICENSE-MIT or http://opensource.org/licenses/MIT)
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.