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
15 use crate::{
16 description::Description,
17 matcher::{Matcher, MatcherBase, MatcherResult},
18 };
19 use std::fmt::Debug;
20
21 /// Matches a container containing all of the items in the given container
22 /// `subset`.
23 ///
24 /// The element type `ElementT` must implement `PartialEq` to allow element
25 /// comparison.
26 ///
27 /// `ActualT` and `ExpectedT` can each be any container which implements
28 /// `IntoIterator`. For instance, `ActualT` and `ExpectedT` can be a
29 /// common container like `&Vec`, arrays or slices. They need not be the same
30 /// container type.
31 ///
32 /// ```
33 /// # use googletest::prelude::*;
34 /// # use std::collections::HashSet;
35 /// # fn should_pass_1() -> Result<()> {
36 /// let value = vec![1, 2, 3];
37 /// verify_that!(value, superset_of([&1, &2]))?; // Passes
38 /// let array_value = [1, 2, 3];
39 /// verify_that!(array_value, superset_of([1, 2]))?; // Passes
40 /// # Ok(())
41 /// # }
42 /// # fn should_fail() -> Result<()> {
43 /// # let value = vec![1, 2, 3];
44 /// verify_that!(value, superset_of([&1, &2, &4]))?; // Fails: 4 is not in the subset
45 /// # Ok(())
46 /// # }
47 /// # should_pass_1().unwrap();
48 /// # should_fail().unwrap_err();
49 ///
50 /// # fn should_pass_2() -> Result<()> {
51 /// let value: HashSet<i32> = [1, 2, 3].into();
52 /// verify_that!(value, superset_of([&1, &2, &3]))?; // Passes
53 /// # Ok(())
54 /// # }
55 /// # should_pass_2().unwrap();
56 /// ```
57 ///
58 /// Item multiplicity in both the actual and expected containers is ignored:
59 ///
60 /// ```
61 /// # use googletest::prelude::*;
62 /// # fn should_pass() -> Result<()> {
63 /// let value: Vec<i32> = vec![0, 0, 1];
64 /// verify_that!(value, superset_of([&0, &1]))?; // Passes
65 /// verify_that!(value, superset_of([&0, &1, &1]))?; // Passes
66 /// # Ok(())
67 /// # }
68 /// # should_pass().unwrap();
69 /// ```
70 ///
71 /// A note on performance: This matcher uses a naive algorithm with a worst-case
72 /// runtime proportional to the *product* of the sizes of the actual and
73 /// expected containers as well as the time to check equality of each pair of
74 /// items. It should not be used on especially large containers.
superset_of<ExpectedT>(subset: ExpectedT) -> SupersetOfMatcher<ExpectedT>75 pub fn superset_of<ExpectedT>(subset: ExpectedT) -> SupersetOfMatcher<ExpectedT> {
76 SupersetOfMatcher { subset }
77 }
78
79 #[derive(MatcherBase)]
80 pub struct SupersetOfMatcher<ExpectedT> {
81 subset: ExpectedT,
82 }
83
84 impl<ElementT: Debug + Copy + PartialEq, ActualT: Debug + Copy, ExpectedT: Debug> Matcher<ActualT>
85 for SupersetOfMatcher<ExpectedT>
86 where
87 ActualT: IntoIterator<Item = ElementT>,
88 for<'a> &'a ExpectedT: IntoIterator<Item = &'a ElementT>,
89 {
matches(&self, actual: ActualT) -> MatcherResult90 fn matches(&self, actual: ActualT) -> MatcherResult {
91 for expected_item in &self.subset {
92 if actual_is_missing(actual, expected_item) {
93 return MatcherResult::NoMatch;
94 }
95 }
96 MatcherResult::Match
97 }
98
explain_match(&self, actual: ActualT) -> Description99 fn explain_match(&self, actual: ActualT) -> Description {
100 let missing_items: Vec<_> = self
101 .subset
102 .into_iter()
103 .filter(|expected_item| actual_is_missing(actual, *expected_item))
104 .map(|expected_item| format!("{expected_item:#?}"))
105 .collect();
106 match missing_items.len() {
107 0 => "whose no element is missing".into(),
108 1 => format!("whose element {} is missing", &missing_items[0]).into(),
109 _ => format!("whose elements {} are missing", missing_items.join(", ")).into(),
110 }
111 }
112
describe(&self, matcher_result: MatcherResult) -> Description113 fn describe(&self, matcher_result: MatcherResult) -> Description {
114 match matcher_result {
115 MatcherResult::Match => format!("is a superset of {:#?}", self.subset).into(),
116 MatcherResult::NoMatch => format!("isn't a superset of {:#?}", self.subset).into(),
117 }
118 }
119 }
120
actual_is_missing<ElementT: PartialEq, ActualT>(actual: ActualT, needle: &ElementT) -> bool where ActualT: IntoIterator<Item = ElementT>,121 fn actual_is_missing<ElementT: PartialEq, ActualT>(actual: ActualT, needle: &ElementT) -> bool
122 where
123 ActualT: IntoIterator<Item = ElementT>,
124 {
125 !actual.into_iter().any(|item| &item == needle)
126 }
127 #[cfg(test)]
128 mod tests {
129 use crate::prelude::*;
130 use indoc::indoc;
131 use std::collections::HashSet;
132
133 #[test]
superset_of_matches_empty_vec() -> Result<()>134 fn superset_of_matches_empty_vec() -> Result<()> {
135 let value: Vec<i32> = vec![];
136 verify_that!(value, superset_of([]))
137 }
138
139 #[test]
superset_of_matches_vec_with_one_element() -> Result<()>140 fn superset_of_matches_vec_with_one_element() -> Result<()> {
141 let value = vec![1];
142 verify_that!(value, superset_of([&1]))
143 }
144
145 #[test]
superset_of_matches_vec_with_two_items() -> Result<()>146 fn superset_of_matches_vec_with_two_items() -> Result<()> {
147 let value = vec![1, 2];
148 verify_that!(value, superset_of([&1, &2]))
149 }
150
151 #[test]
superset_of_matches_vec_when_actual_has_excess_element() -> Result<()>152 fn superset_of_matches_vec_when_actual_has_excess_element() -> Result<()> {
153 let value = vec![1, 2, 3];
154 verify_that!(value, superset_of([&1, &2]))
155 }
156
157 #[test]
superset_of_matches_vec_when_actual_has_excess_element_first() -> Result<()>158 fn superset_of_matches_vec_when_actual_has_excess_element_first() -> Result<()> {
159 let value = vec![3, 1, 2];
160 verify_that!(value, superset_of([&1, &2]))
161 }
162
163 #[test]
superset_of_matches_slice_with_one_element() -> Result<()>164 fn superset_of_matches_slice_with_one_element() -> Result<()> {
165 let value = &[1];
166 verify_that!(value, superset_of([&1]))
167 }
168
169 #[test]
superset_of_matches_hash_set_with_one_element() -> Result<()>170 fn superset_of_matches_hash_set_with_one_element() -> Result<()> {
171 let value: HashSet<i32> = [1].into();
172 verify_that!(value, superset_of([&1]))
173 }
174
175 #[test]
superset_of_does_not_match_when_first_element_does_not_match() -> Result<()>176 fn superset_of_does_not_match_when_first_element_does_not_match() -> Result<()> {
177 let value = vec![0];
178 verify_that!(value, not(superset_of([&1])))
179 }
180
181 #[test]
superset_of_does_not_match_when_second_element_does_not_match() -> Result<()>182 fn superset_of_does_not_match_when_second_element_does_not_match() -> Result<()> {
183 let value = vec![2];
184 verify_that!(value, not(superset_of([&2, &0])))
185 }
186
187 #[test]
superset_of_shows_correct_message_when_first_item_does_not_match() -> Result<()>188 fn superset_of_shows_correct_message_when_first_item_does_not_match() -> Result<()> {
189 let result = verify_that!(vec![0, 2, 3], superset_of([&1, &2, &3]));
190
191 verify_that!(
192 result,
193 err(displays_as(contains_substring(indoc!(
194 "
195 Value of: vec![0, 2, 3]
196 Expected: is a superset of [
197 1,
198 2,
199 3,
200 ]
201 Actual: [0, 2, 3],
202 whose element 1 is missing
203 "
204 ))))
205 )
206 }
207
208 #[test]
superset_of_shows_correct_message_when_second_item_does_not_match() -> Result<()>209 fn superset_of_shows_correct_message_when_second_item_does_not_match() -> Result<()> {
210 let result = verify_that!(vec![1, 0, 3], superset_of([&1, &2, &3]));
211
212 verify_that!(
213 result,
214 err(displays_as(contains_substring(indoc!(
215 "
216 Value of: vec![1, 0, 3]
217 Expected: is a superset of [
218 1,
219 2,
220 3,
221 ]
222 Actual: [1, 0, 3],
223 whose element 2 is missing
224 "
225 ))))
226 )
227 }
228
229 #[test]
superset_of_shows_correct_message_when_first_two_items_do_not_match() -> Result<()>230 fn superset_of_shows_correct_message_when_first_two_items_do_not_match() -> Result<()> {
231 let result = verify_that!(vec![0, 0, 3], superset_of([&1, &2, &3]));
232
233 verify_that!(
234 result,
235 err(displays_as(contains_substring(indoc!(
236 "
237 Value of: vec![0, 0, 3]
238 Expected: is a superset of [
239 1,
240 2,
241 3,
242 ]
243 Actual: [0, 0, 3],
244 whose elements 1, 2 are missing
245 "
246 ))))
247 )
248 }
249 }
250