[−][src]Crate pretty_assertions
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:
ⓘThis example is not tested
use pretty_assertions::{assert_eq, assert_ne};
Show the example behind the screenshots above.
ⓘThis example is not tested
// 1. add the `pretty_assertions` dependency to `Cargo.toml`. // 2. insert this line at the top of each module, as needed use pretty_assertions::{assert_eq, assert_ne}; fn main() { #[derive(Debug, PartialEq)] struct Foo { lorem: &'static str, ipsum: u32, dolor: Result<String, String>, } let x = Some(Foo { lorem: "Hello World!", ipsum: 42, dolor: Ok("hey".to_string())}); let y = Some(Foo { lorem: "Hello Wrold!", ipsum: 42, dolor: Ok("hey ho!".to_string())}); assert_eq!(x, y); }
Tip
Specify it as [dev-dependencies]
and it will only be used for compiling tests, examples, and benchmarks.
This way the compile time of cargo build
won't be affected!
Also add #[cfg(test)]
to your use
statements, like this:
ⓘThis example is not tested
#[cfg(test)] use pretty_assertions::{assert_eq, assert_ne};
Note
- Since
Rust 2018
edition, you need to declareuse pretty_assertions::{assert_eq, assert_ne};
per module. Before you would write#[macro_use] extern crate pretty_assertions;
. - The replacement is only effective in your own crate, not in other libraries you include.
assert_ne
is also switched to multi-line presentation, but does not show a diff.
Macros
assert_eq | |
assert_ne |
Structs
Style | A style is a collection of properties that can format a string using ANSI escape codes. |