googletest/matchers/
not_matcher.rs

1// Copyright 2022 Google LLC
2//
3// Licensed under the Apache License, Version 2.0 (the "License");
4// you may not use this file except in compliance with the License.
5// You may obtain a copy of the License at
6//
7//      http://www.apache.org/licenses/LICENSE-2.0
8//
9// Unless required by applicable law or agreed to in writing, software
10// distributed under the License is distributed on an "AS IS" BASIS,
11// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12// See the License for the specific language governing permissions and
13// limitations under the License.
14
15use crate::{
16    description::Description,
17    matcher::{Matcher, MatcherBase, MatcherResult},
18};
19use std::fmt::Debug;
20
21/// Matches the actual value exactly when the inner matcher does _not_ match.
22///
23/// ```
24/// # use googletest::prelude::*;
25/// # fn should_pass() -> Result<()> {
26/// verify_that!(0, not(eq(1)))?; // Passes
27/// #     Ok(())
28/// # }
29/// # fn should_fail() -> Result<()> {
30/// verify_that!(0, not(eq(0)))?; // Fails
31/// #     Ok(())
32/// # }
33/// # should_pass().unwrap();
34/// # should_fail().unwrap_err();
35/// ```
36pub fn not<InnerMatcherT>(inner: InnerMatcherT) -> NotMatcher<InnerMatcherT> {
37    NotMatcher { inner }
38}
39
40#[derive(MatcherBase)]
41pub struct NotMatcher<InnerMatcherT> {
42    inner: InnerMatcherT,
43}
44
45impl<T: Debug + Copy, InnerMatcherT: Matcher<T>> Matcher<T> for NotMatcher<InnerMatcherT> {
46    fn matches(&self, actual: T) -> MatcherResult {
47        match self.inner.matches(actual) {
48            MatcherResult::Match => MatcherResult::NoMatch,
49            MatcherResult::NoMatch => MatcherResult::Match,
50        }
51    }
52
53    fn explain_match(&self, actual: T) -> Description {
54        self.inner.explain_match(actual)
55    }
56
57    fn describe(&self, matcher_result: MatcherResult) -> Description {
58        self.inner.describe(if matcher_result.into() {
59            MatcherResult::NoMatch
60        } else {
61            MatcherResult::Match
62        })
63    }
64}
65
66#[cfg(test)]
67mod tests {
68    use crate::matcher::MatcherResult;
69    use crate::prelude::*;
70    use crate::Result;
71    use indoc::indoc;
72
73    #[test]
74    fn matches_when_inner_matcher_does_not_match() -> Result<()> {
75        let matcher = not(eq(1));
76
77        let result = matcher.matches(0);
78
79        verify_that!(result, eq(MatcherResult::Match))
80    }
81
82    #[test]
83    fn does_not_match_when_inner_matcher_matches() -> Result<()> {
84        let matcher = not(eq(1));
85
86        let result = matcher.matches(1);
87
88        verify_that!(result, eq(MatcherResult::NoMatch))
89    }
90
91    #[test]
92    fn match_explanation_references_actual_value() -> Result<()> {
93        let result = verify_that!(&[1], not(container_eq([1])));
94
95        verify_that!(
96            result,
97            err(displays_as(contains_substring(indoc!(
98                "
99                Actual: [1],
100                  which contains all the elements
101                "
102            ))))
103        )
104    }
105}
googletest/matchers/not_matcher.rs

googletest/matchers/
not_matcher.rs
