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// Copyright 2023 Google LLC
// Copyright 2026 Bradford Hovinen <bradford@hovinen.me>
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
#![doc(hidden)]
use crate::{
description::Description,
matcher::{Describable, Matcher, MatcherResult},
};
use core::fmt::Debug;
/// Matches precisely values matched by `inner`.
///
/// The returned matcher produces a description prefixed by the string
/// `description`. This is useful in contexts where the test assertion failure
/// output must include the additional description.
pub fn is<'a, InnerMatcherT>(
description: &'a str,
inner: InnerMatcherT,
) -> IsMatcher<'a, InnerMatcherT> {
IsMatcher { description, inner }
}
#[doc(hidden)]
pub struct IsMatcher<'a, InnerMatcherT> {
description: &'a str,
inner: InnerMatcherT,
}
impl<'a, ActualT: Debug + ?Sized, InnerMatcherT: Matcher<ActualT>> Matcher<ActualT>
for IsMatcher<'a, InnerMatcherT>
{
fn matches(&self, actual: &ActualT) -> MatcherResult {
self.inner.matches(actual)
}
fn explain_match(&self, actual: &ActualT) -> Description {
self.inner.explain_match(actual)
}
}
impl<'a, InnerMatcherT: Describable> Describable for IsMatcher<'a, InnerMatcherT> {
fn describe(&self, matcher_result: MatcherResult) -> Description {
match matcher_result {
MatcherResult::Match => format!(
"is {} which {}",
self.description,
self.inner.describe(MatcherResult::Match)
)
.into(),
MatcherResult::NoMatch => format!(
"is not {} which {}",
self.description,
self.inner.describe(MatcherResult::Match)
)
.into(),
}
}
}