Overwrite assert_eq! with a drop-in replacement, adding a colorful diff.
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:
rust,ignore
use pretty_assertions::{assert_eq, assert_ne};
Show the example behind the screenshots above.
``rust,ignore
// 1. add theprettyassertionsdependency toCargo.toml`.
// 2. insert this line at the top of each module, as needed
use prettyassertions::{asserteq, assertne};
fn main() {
#[derive(Debug, PartialEq)]
struct Foo {
lorem: &'static str,
ipsum: u32,
dolor: Result
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);
} ```
The exact output of assertions is not guaranteed to be consistent over time, and may change between minor versions. The output of this crate is designed to be read by a human. It is not suitable for exact comparison, for example in snapshot testing.
This crate adheres to semantic versioning for publically exported crate items, except the private module, which may change between any version.
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:
```rust,ignore
use prettyassertions::{asserteq, assert_ne}; ```
Rust 2018 edition, you need to declare
use pretty_assertions::{assert_eq, assert_ne}; per module.
Before you would write #[macro_use] extern crate pretty_assertions;.assert_ne is also switched to multi-line presentation, but does not show
a diff.no_std supportFor no_std support, disable the std feature and enable the alloc feature:
```toml
pretty_assertions = { version= "...", default-features = false, features = ["alloc"] } ```
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