Function xpct::eq_diff

pub fn eq_diff<'a, Actual, Expected>(
    expected: Expected
) -> Matcher<'a, Actual, Actual>where
    Actual: Debug + PartialEq<Expected> + Eq + 'a,
    Expected: Debug + Diffable<Actual> + 'a,

Available on crate feature diff only.

Succeeds when the actual value equals the expected value and shows a diff otherwise.

This matcher is functionally identical to equal, except it shows a diff if the values are not equal. You can use this matcher with any type that implements Diffable, and you can implement Diffable for your own types.

Out of the box, you can diff strings, slices, sets, and maps.

Examples

use xpct::{expect, eq_diff};

expect!("diffing strings").to(eq_diff("diffing strings"));

use xpct::{expect, eq_diff};

expect!(["slices", "too"]).to(eq_diff(["slices", "too"]));

Custom Styling

This matcher relies on text styling to distinguish added and removed values in string diffs. If the provided text styling for diffs is inaccessible for you, or you prefer to have text styling disabled, you can override the provided styling.

To do this, write a custom style sheet using DiffStyle and write your own matcher function that calls EqDiffMatcher.

This example makes string diffs readable without text styling:

use std::fmt;

use xpct::core::Matcher;
use xpct::format::diff::{DiffFormat, DiffSegmentStyle, DiffStyle};
use xpct::matchers::diff::{Diffable, EqDiffMatcher};

pub fn eq_diff<'a, Actual, Expected>(expected: Expected) -> Matcher<'a, Actual, Actual>
where
    Actual: fmt::Debug + PartialEq<Expected> + Eq + 'a,
    Expected: Diffable<Actual> + fmt::Debug + 'a,
{
    let mut custom_style = DiffStyle::provided();

    custom_style.string.format = DiffSegmentStyle {
        insert: String::from("+(%s)"),
        delete: String::from("-(%s)"),
        equal: String::from("%s"),
    };

    Matcher::new(
        EqDiffMatcher::new(expected),
        DiffFormat::<Actual, Expected>::new(custom_style),
    )
}