1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504 505 506 507 508 509 510 511 512 513 514 515 516 517 518 519 520 521 522 523 524 525 526 527 528 529 530 531 532 533 534 535 536 537 538 539 540 541 542 543 544 545 546 547 548 549 550 551 552 553 554 555 556 557 558 559 560 561 562 563 564 565 566 567 568 569 570 571 572 573 574 575 576 577 578 579 580 581 582 583 584 585 586 587 588 589 590 591 592 593 594 595 596 597 598 599 600 601 602 603 604 605 606 607 608 609 610 611 612 613 614 615 616 617 618 619 620 621 622 623 624 625 626 627 628 629 630 631 632 633 634 635 636 637 638 639 640 641 642 643 644 645 646 647 648 649 650 651 652 653 654 655 656 657 658 659 660 661 662 663 664 665 666 667 668 669 670 671 672 673 674 675 676 677 678 679 680 681 682 683 684 685 686 687 688 689 690 691 692 693 694 695 696 697 698 699 700 701 702 703 704 705 706 707 708 709 710 711 712 713 714 715 716 717 718 719 720 721 722 723 724 725 726 727 728 729 730 731 732 733 734 735 736 737 738 739 740 741 742 743 744 745 746 747 748 749 750 751 752 753 754 755 756 757 758 759 760 761 762 763 764 765 766 767 768 769 770 771 772 773 774 775 776 777 778 779 780 781 782 783 784 785 786 787 788 789 790 791 792 793 794 795 796 797 798 799 800 801 802 803 804 805 806 807 808 809 810 811 812 813 814 815 816 817 818 819 820 821 822 823 824 825 826 827 828 829 830 831 832 833 834 835 836 837 838 839 840 841 842 843 844 845 846 847 848 849 850 851 852 853 854 855 856 857 858 859 860 861 862 863 864 865 866 867 868 869 870 871 872 873 874 875 876 877 878 879 880 881 882 883 884 885 886 887 888 889 890 891 892 893 894 895 896 897 898 899 900 901 902 903 904 905 906 907 908 909 910 911 912 913 914
// Copyright 2022 Google LLC
//
// 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.
// There are no visible documentation elements in this module; the declarative
// macro is documented in the matchers module.
#![doc(hidden)]
/// Matches a container whose elements in any order have a 1:1 correspondence
/// with the provided element matchers.
///
/// ```
/// # use googletest::prelude::*;
/// # fn should_pass() -> Result<()> {
/// verify_that!(vec![3, 2, 1], unordered_elements_are![eq(&1), ge(&2), anything()])?; // Passes
/// # Ok(())
/// # }
/// # fn should_fail_1() -> Result<()> {
/// verify_that!(vec![1], unordered_elements_are![eq(&1), ge(&2)])?; // Fails: container has wrong size
/// # Ok(())
/// # }
/// # fn should_fail_2() -> Result<()> {
/// verify_that!(vec![3, 2, 1], unordered_elements_are![eq(&1), ge(&4), eq(&2)])?; // Fails: second matcher not matched
/// # Ok(())
/// # }
/// # fn should_fail_3() -> Result<()> {
/// verify_that!(vec![3, 2, 1], unordered_elements_are![ge(&3), ge(&3), ge(&3)])?; // Fails: no 1:1 correspondence
/// # Ok(())
/// # }
/// # should_pass().unwrap();
/// # should_fail_1().unwrap_err();
/// # should_fail_2().unwrap_err();
/// # should_fail_3().unwrap_err();
/// ```
///
/// The actual value must be a container such as a `&Vec`, an array, or a
/// slice. More precisely, the actual value must implement [`IntoIterator`].
///
/// This can also be omitted in [`verify_that!`] macros and replaced with curly
/// brackets.
///
/// ```
/// # use googletest::prelude::*;
/// verify_that!(vec![1, 2], {eq(&2), eq(&1)})
/// # .unwrap();
/// ```
///
/// Note: This behavior is only possible in [`verify_that!`] macros. In any
/// other cases, it is still necessary to use the
/// [`unordered_elements_are!`][crate::matchers::unordered_elements_are] macro.
///
/// ```compile_fail
/// # use googletest::prelude::*;
/// verify_that!(vec![vec![1,2], vec![3]], {{eq(2), eq(1)}, {eq(3)}})
/// # .unwrap();
/// ```
///
/// Use this instead:
/// ```
/// # use googletest::prelude::*;
/// verify_that!(vec![vec![1,2], vec![3]],
/// {unordered_elements_are![eq(&2), eq(&1)], unordered_elements_are![eq(&3)]})
/// # .unwrap();
/// ```
///
/// If an inner matcher is `eq(...)`, it can be omitted:
///
/// ```
/// # use googletest::prelude::*;
///
/// verify_that!(vec![1,2,3], unordered_elements_are![lt(&2), gt(&1), &3])
/// # .unwrap();
/// ```
///
/// The matcher proceeds in three stages:
///
/// 1. It first checks whether the actual value is of the right size to possibly
/// be matched by each of the given matchers. If not, then it immediately
/// fails explaining that the size is incorrect.
///
/// 2. It then checks whether each matcher matches at least one corresponding
/// element in the actual container and each element in the actual container
/// is matched by at least one matcher. If not, it fails with a message
/// indicating which matcher respectively container elements had no
/// counterparts.
///
/// 3. Finally, it checks whether the mapping of matchers to corresponding
/// actual elements is a 1-1 correspondence and fails if that is not the
/// case. The failure message then shows the best matching it could find,
/// including which matchers did not have corresponding unique elements in
/// the container and which container elements had no corresponding matchers.
///
/// [`IntoIterator`]: std::iter::IntoIterator
/// [`Iterator`]: std::iter::Iterator
/// [`Iterator::collect`]: std::iter::Iterator::collect
/// [`Vec`]: std::vec::Vec
#[macro_export]
#[doc(hidden)]
macro_rules! __unordered_elements_are {
($(,)?) => {{
$crate::matchers::__internal_unstable_do_not_depend_on_these::
UnorderedElementsAreMatcher::new(
[],
$crate::matchers::__internal_unstable_do_not_depend_on_these::
Requirements::PerfectMatch)
}};
($($matcher:expr),* $(,)?) => {{
$crate::matchers::__internal_unstable_do_not_depend_on_these::
UnorderedElementsAreMatcher::new(
[$(Box::new(
$crate::matcher_support::__internal_unstable_do_not_depend_on_these::auto_eq!(
$matcher
)
)),*],
$crate::matchers::__internal_unstable_do_not_depend_on_these::
Requirements::PerfectMatch)
}};
}
/// Matches a container containing elements matched by the given matchers.
///
/// To match, each given matcher must have a corresponding element in the
/// container which it matches. There must be a mapping uniquely matching each
/// matcher to a container element. The container can, however, contain
/// additional elements that don't correspond to any matcher.
///
/// Put another way, `contains_each!` matches if there is a subset of the actual
/// container which
/// [`unordered_elements_are`][crate::matchers::unordered_elements_are] would
/// match.
///
/// ```
/// # use googletest::prelude::*;
/// # fn should_pass() -> Result<()> {
/// verify_that!(vec![3, 2, 1], contains_each![eq(&2), ge(&3)])?; // Passes
/// verify_that!(vec![3, 2, 1], contains_each![ge(&2), ge(&2)])?; // Passes
/// # Ok(())
/// # }
/// # fn should_fail_1() -> Result<()> {
/// verify_that!(vec![1], contains_each![eq(&1), ge(&2)])?; // Fails: container too small
/// # Ok(())
/// # }
/// # fn should_fail_2() -> Result<()> {
/// verify_that!(vec![3, 2, 1], contains_each![eq(&1), ge(&4)])?; // Fails: second matcher unmatched
/// # Ok(())
/// # }
/// # fn should_fail_3() -> Result<()> {
/// verify_that!(vec![3, 2, 1], contains_each![ge(&3), ge(&3), ge(&3)])?; // Fails: no matching
/// # Ok(())
/// # }
/// # should_pass().unwrap();
/// # should_fail_1().unwrap_err();
/// # should_fail_2().unwrap_err();
/// # should_fail_3().unwrap_err();
/// ```
///
/// The actual value must be a container such as a `&Vec`, an array, or a
/// slice. More precisely, the actual value must implement [`IntoIterator`].
///
/// If an inner matcher is `eq(...)`, it can be omitted:
///
/// ```
/// # use googletest::prelude::*;
///
/// verify_that!(vec![1,2,3], contains_each![lt(&2), &3])
/// # .unwrap();
/// ```
///
/// The matcher proceeds in three stages:
///
/// 1. It first checks whether the actual value is large enough to possibly be
/// matched by each of the given matchers. If not, then it immediately fails
/// explaining that the size is too small.
///
/// 2. It then checks whether each matcher matches at least one corresponding
/// element in the actual container and fails if that is not the case. The
/// failure message indicates which matcher had no corresponding element.
///
/// 3. Finally, it checks whether the mapping of matchers to corresponding
/// actual elements is 1-1 and fails if that is not the case. The failure
/// message then shows the best matching it could find, including which
/// matchers did not have corresponding unique elements in the container.
///
/// [`IntoIterator`]: std::iter::IntoIterator
/// [`Iterator`]: std::iter::Iterator
/// [`Iterator::collect`]: std::iter::Iterator::collect
/// [`Vec`]: std::vec::Vec
#[macro_export]
#[doc(hidden)]
macro_rules! __contains_each {
($(,)?) => {{
$crate::matchers::__internal_unstable_do_not_depend_on_these::
UnorderedElementsAreMatcher::new(
[],
$crate::matchers::__internal_unstable_do_not_depend_on_these::Requirements::Superset)
}};
($($matcher:expr),* $(,)?) => {{
$crate::matchers::__internal_unstable_do_not_depend_on_these::
UnorderedElementsAreMatcher::new(
[$(Box::new(
$crate::matcher_support::__internal_unstable_do_not_depend_on_these::auto_eq!(
$matcher
)
)),*],
$crate::matchers::__internal_unstable_do_not_depend_on_these::Requirements::Superset)
}}
}
/// Matches a container all of whose elements are matched by the given matchers.
///
/// To match, each element in the container must have a corresponding matcher
/// which matches it. There must be a 1-1 mapping from container elements to
/// matchers, so that no matcher has more than one corresponding element.
///
/// There may, however, be matchers not corresponding to any elements in the
/// container.
///
/// Put another way, `is_contained_in!` matches if there is a subset of the
/// matchers which would match with
/// [`unordered_elements_are`][crate::matchers::unordered_elements_are].
///
/// ```
/// # use googletest::prelude::*;
/// # fn should_pass() -> Result<()> {
/// verify_that!(vec![2, 1], is_contained_in![eq(&1), ge(&2)])?; // Passes
/// verify_that!(vec![2, 1], is_contained_in![ge(&1), ge(&1)])?; // Passes
/// # Ok(())
/// # }
/// # fn should_fail_1() -> Result<()> {
/// verify_that!(vec![1, 2, 3], is_contained_in![eq(&1), ge(&2)])?; // Fails: container too large
/// # Ok(())
/// # }
/// # fn should_fail_2() -> Result<()> {
/// verify_that!(vec![2, 1], is_contained_in![eq(&1), ge(&4)])?; // Fails: second matcher unmatched
/// # Ok(())
/// # }
/// # fn should_fail_3() -> Result<()> {
/// verify_that!(vec![3, 1], is_contained_in![ge(&3), ge(&3), ge(&3)])?; // Fails: no matching
/// # Ok(())
/// # }
/// # should_pass().unwrap();
/// # should_fail_1().unwrap_err();
/// # should_fail_2().unwrap_err();
/// # should_fail_3().unwrap_err();
/// ```
///
/// The actual value must be a container such as a `&Vec`, an array, or a slice.
/// More precisely, the actual value must implement [`IntoIterator`].
///
/// If an inner matcher is `eq(...)`, it can be omitted:
///
/// ```
/// # use googletest::prelude::*;
///
/// verify_that!(vec![1,2,3], is_contained_in![lt(&2), &3, &4, gt(&0)])
/// # .unwrap();
/// ```
///
/// The matcher proceeds in three stages:
///
/// 1. It first checks whether the actual value is too large to possibly be
/// matched by each of the given matchers. If so, it immediately fails
/// explaining that the size is too large.
///
/// 2. It then checks whether each actual container element is matched by at
/// least one matcher and fails if that is not the case. The failure message
/// indicates which element had no corresponding matcher.
///
/// 3. Finally, it checks whether the mapping of elements to corresponding
/// matchers is 1-1 and fails if that is not the case. The failure message
/// then shows the best matching it could find, including which container
/// elements did not have corresponding matchers.
///
/// [`IntoIterator`]: std::iter::IntoIterator
/// [`Iterator`]: std::iter::Iterator
/// [`Iterator::collect`]: std::iter::Iterator::collect
/// [`Vec`]: std::vec::Vec
#[macro_export]
#[doc(hidden)]
macro_rules! __is_contained_in {
($(,)?) => {{
$crate::matchers::__internal_unstable_do_not_depend_on_these::
UnorderedElementsAreMatcher::new(
[], $crate::matchers::__internal_unstable_do_not_depend_on_these::Requirements::Subset)
}};
($($matcher:expr),* $(,)?) => {{
$crate::matchers::__internal_unstable_do_not_depend_on_these::
UnorderedElementsAreMatcher::new(
[$(Box::new(
$crate::matcher_support::__internal_unstable_do_not_depend_on_these::auto_eq!(
$matcher
)
)),*],
$crate::matchers::__internal_unstable_do_not_depend_on_these::Requirements::Subset)
}}
}
/// Module for use only by the macros in this module.
///
/// **For internal use only. API stablility is not guaranteed!**
#[doc(hidden)]
pub mod internal {
use crate::description::Description;
use crate::matcher::{Matcher, MatcherBase, MatcherResult};
use crate::matcher_support::count_elements::count_elements;
use std::collections::HashSet;
use std::fmt::{Debug, Display};
/// This struct is meant to be used only through the
/// `unordered_elements_are![...]` macro.
///
/// **For internal use only. API stablility is not guaranteed!**
#[doc(hidden)]
#[derive(MatcherBase)]
pub struct UnorderedElementsAreMatcher<'a, T: Debug + Copy, const N: usize> {
elements: [Box<dyn Matcher<T> + 'a>; N],
requirements: Requirements,
}
impl<'a, T: Debug + Copy, const N: usize> UnorderedElementsAreMatcher<'a, T, N> {
pub fn new(elements: [Box<dyn Matcher<T> + 'a>; N], requirements: Requirements) -> Self {
Self { elements, requirements }
}
}
// This matcher performs the checks in three different steps in both `matches`
// and `explain_match`. This is useful for performance but also to produce
// an actionable error message.
// 1. `UnorderedElementsAreMatcher` verifies that both collections have the same
// size
// 2. `UnorderedElementsAreMatcher` verifies that each actual element matches at
// least one expected element and vice versa.
// 3. `UnorderedElementsAreMatcher` verifies that a perfect matching exists
// using Ford-Fulkerson.
impl<'a, T: Debug + Copy, ContainerT: Debug + Copy, const N: usize> Matcher<ContainerT>
for UnorderedElementsAreMatcher<'a, T, N>
where
ContainerT: IntoIterator<Item = T>,
{
fn matches(&self, actual: ContainerT) -> MatcherResult {
let match_matrix = MatchMatrix::generate(actual, &self.elements);
match_matrix.is_match_for(self.requirements).into()
}
fn explain_match(&self, actual: ContainerT) -> Description {
if let Some(size_mismatch_explanation) =
self.requirements.explain_size_mismatch(actual, N)
{
return size_mismatch_explanation;
}
let match_matrix = MatchMatrix::generate(actual, &self.elements);
if let Some(unmatchable_explanation) =
match_matrix.explain_unmatchable(self.requirements)
{
return unmatchable_explanation;
}
let best_match = match_matrix.find_best_match();
best_match
.get_explanation(actual, &self.elements, self.requirements)
.unwrap_or("whose elements all match".into())
}
fn describe(&self, matcher_result: MatcherResult) -> Description {
format!(
"{} elements matching in any order:\n{}",
if matcher_result.into() { "contains" } else { "doesn't contain" },
self.elements
.iter()
.map(|matcher| matcher.describe(MatcherResult::Match))
.collect::<Description>()
.enumerate()
.indent()
)
.into()
}
}
/// The requirements of the mapping between matchers and actual values by
/// which [`UnorderedElementsAre`] is deemed to match its input.
///
/// **For internal use only. API stablility is not guaranteed!**
#[doc(hidden)]
#[derive(Clone, Copy)]
pub enum Requirements {
/// There must be a 1:1 correspondence between the actual values and the
/// matchers.
PerfectMatch,
/// The mapping from matched actual values to their corresponding
/// matchers must be surjective.
Superset,
/// The mapping from matchers to matched actual values must be
/// surjective.
Subset,
}
impl Requirements {
fn explain_size_mismatch<ContainerT: IntoIterator + Copy>(
&self,
actual: ContainerT,
expected_size: usize,
) -> Option<Description> {
let actual_size = count_elements(actual);
match self {
Requirements::PerfectMatch if actual_size != expected_size => Some(
format!("which has size {} (expected {})", actual_size, expected_size).into(),
),
Requirements::Superset if actual_size < expected_size => Some(
format!("which has size {} (expected at least {})", actual_size, expected_size)
.into(),
),
Requirements::Subset if actual_size > expected_size => Some(
format!("which has size {} (expected at most {})", actual_size, expected_size)
.into(),
),
_ => None,
}
}
}
impl Display for Requirements {
fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
match self {
Requirements::PerfectMatch => {
write!(f, "perfect")
}
Requirements::Superset => {
write!(f, "superset")
}
Requirements::Subset => {
write!(f, "subset")
}
}
}
}
/// The bipartite matching graph between actual and expected elements.
struct MatchMatrix<const N: usize>(Vec<[MatcherResult; N]>);
impl<const N: usize> MatchMatrix<N> {
fn generate<'a, T: Debug + Copy + 'a, ContainerT: Debug + Copy + IntoIterator<Item = T>>(
actual: ContainerT,
expected: &[Box<dyn Matcher<T> + 'a>; N],
) -> Self {
let mut matrix = MatchMatrix(vec![[MatcherResult::NoMatch; N]; count_elements(actual)]);
for (actual_idx, actual) in actual.into_iter().enumerate() {
for (expected_idx, expected) in expected.iter().enumerate() {
matrix.0[actual_idx][expected_idx] = expected.matches(actual);
}
}
matrix
}
fn is_match_for(&self, requirements: Requirements) -> bool {
match requirements {
Requirements::PerfectMatch => {
!self.find_unmatchable_elements().has_unmatchable_elements()
&& self.find_best_match().is_full_match()
}
Requirements::Superset => {
!self.find_unmatched_expected().has_unmatchable_elements()
&& self.find_best_match().is_superset_match()
}
Requirements::Subset => {
!self.find_unmatched_actual().has_unmatchable_elements()
&& self.find_best_match().is_subset_match()
}
}
}
fn explain_unmatchable(&self, requirements: Requirements) -> Option<Description> {
let unmatchable_elements = match requirements {
Requirements::PerfectMatch => self.find_unmatchable_elements(),
Requirements::Superset => self.find_unmatched_expected(),
Requirements::Subset => self.find_unmatched_actual(),
};
unmatchable_elements.get_explanation()
}
// Verifies that each actual matches at least one expected and that
// each expected matches at least one actual.
// This is a necessary condition but not sufficient. But it is faster
// than `find_best_match()`.
fn find_unmatchable_elements(&self) -> UnmatchableElements<N> {
let unmatchable_actual =
self.0.iter().map(|row| row.iter().all(|&e| e.is_no_match())).collect();
let mut unmatchable_expected = [false; N];
for (col_idx, expected) in unmatchable_expected.iter_mut().enumerate() {
*expected = self.0.iter().map(|row| row[col_idx]).all(|e| e.is_no_match());
}
UnmatchableElements { unmatchable_actual, unmatchable_expected }
}
fn find_unmatched_expected(&self) -> UnmatchableElements<N> {
let mut unmatchable_expected = [false; N];
for (col_idx, expected) in unmatchable_expected.iter_mut().enumerate() {
*expected = self.0.iter().map(|row| row[col_idx]).all(|e| e.is_no_match());
}
UnmatchableElements { unmatchable_actual: vec![false; N], unmatchable_expected }
}
fn find_unmatched_actual(&self) -> UnmatchableElements<N> {
let unmatchable_actual =
self.0.iter().map(|row| row.iter().all(|e| e.is_no_match())).collect();
UnmatchableElements { unmatchable_actual, unmatchable_expected: [false; N] }
}
// Verifies that a full match exists.
//
// Uses the well-known Ford-Fulkerson max flow method to find a maximum
// bipartite matching. Flow is considered to be from actual to expected.
// There is an implicit source node that is connected to all of the actual
// nodes, and an implicit sink node that is connected to all of the
// expected nodes. All edges have unit capacity.
//
// Neither the flow graph nor the residual flow graph are represented
// explicitly. Instead, they are implied by the information in `self.0` and
// the local `actual_match : [Option<usize>; N]` whose elements are initialized
// to `None`. This represents the initial state of the algorithm,
// where the flow graph is empty, and the residual flow graph has the
// following edges:
// - An edge from source to each actual element node
// - An edge from each expected element node to sink
// - An edge from each actual element node to each expected element node, if
// the actual element matches the expected element, i.e.
// `matches!(self.0[actual_id][expected_id], Matches)`
//
// When the `try_augment(...)` method adds a flow, it sets `actual_match[l] =
// Some(r)` for some nodes l and r. This induces the following changes:
// - The edges (source, l), (l, r), and (r, sink) are added to the flow graph.
// - The same three edges are removed from the residual flow graph.
// - The reverse edges (l, source), (r, l), and (sink, r) are added to the
// residual flow graph, which is a directional graph representing unused
// flow capacity.
//
// When the method augments a flow (changing `actual_match[l]` from `Some(r1)`
// to `Some(r2)`), this can be thought of as "undoing" the above steps
// with respect to r1 and "redoing" them with respect to r2.
//
// It bears repeating that the flow graph and residual flow graph are
// never represented explicitly, but can be derived by looking at the
// information in 'self.0' and in `actual_match`.
//
// As an optimization, there is a second local `expected_match: [Option<usize>;
// N]` which does not provide any new information. Instead, it enables
// more efficient queries about edges entering or leaving the expected elements
// nodes of the flow or residual flow graphs. The following invariants
// are maintained:
//
// actual_match[a] == None or expected_match[actual_match[a].unwrap()] ==
// Some(a)
// expected_match[r] == None or actual_match[expected_match[e].unwrap()] ==
// Some(e)
//
// | [ source ] |
// | ||| |
// | ||| |
// | ||\-> actual_match[0]=Some(1) -\ expected_match[0]=None ---\ |
// | || | | |
// | |\--> actual_match[1]=None \-> expected_match[1]=Some(0) --\| |
// | | || |
// | \---> actual_match[2]=Some(2) --> expected_match[2]=Some(2) -\|| |
// | ||| |
// | elements matchers vvv |
// | [ sink ] |
//
// See Also:
// [1] Cormen, et al (2001). "Section 26.2: The Ford-Fulkerson method".
// "Introduction to Algorithms (Second ed.)", pp. 651-664.
// [2] "Ford-Fulkerson algorithm", Wikipedia,
// 'http://en.wikipedia.org/wiki/Ford%E2%80%93Fulkerson_algorithm'
fn find_best_match(&self) -> BestMatch<N> {
let mut actual_match = vec![None; self.0.len()];
let mut expected_match: [Option<usize>; N] = [None; N];
// Searches the residual flow graph for a path from each actual node to
// the sink in the residual flow graph, and if one is found, add this path
// to the graph.
// It's okay to search through the actual nodes once. The
// edge from the implicit source node to each previously-visited actual
// node will have flow if that actual node has any path to the sink
// whatsoever. Subsequent augmentations can only add flow to the
// network, and cannot take away that previous flow unit from the source.
// Since the source-to-actual edge can only carry one flow unit (or,
// each actual element can be matched to only one expected element), there is no
// need to visit the actual nodes more than once looking for
// augmented paths. The flow is known to be possible or impossible
// by looking at the node once.
for actual_idx in 0..self.0.len() {
assert!(actual_match[actual_idx].is_none());
let mut seen = [false; N];
self.try_augment(actual_idx, &mut seen, &mut actual_match, &mut expected_match);
}
BestMatch(actual_match)
}
// Perform a depth-first search from actual node `actual_idx` to the sink by
// searching for an unassigned expected node. If a path is found, flow
// is added to the network by linking the actual and expected vector elements
// corresponding each segment of the path. Returns true if a path to
// sink was found, which means that a unit of flow was added to the
// network. The 'seen' array elements correspond to expected nodes and are
// marked to eliminate cycles from the search.
//
// Actual nodes will only be explored at most once because they
// are accessible from at most one expected node in the residual flow
// graph.
//
// Note that `actual_match[actual_idx]` is the only element of `actual_match`
// that `try_augment(...)` will potentially transition from `None` to
// `Some(...)`. Any other `actual_match` element holding `None` before
// `try_augment(...)` will be holding it when `try_augment(...)`
// returns.
//
fn try_augment(
&self,
actual_idx: usize,
seen: &mut [bool; N],
actual_match: &mut [Option<usize>],
expected_match: &mut [Option<usize>; N],
) -> bool {
for expected_idx in 0..N {
if seen[expected_idx] {
continue;
}
if self.0[actual_idx][expected_idx].is_no_match() {
continue;
}
// There is an edge between `actual_idx` and `expected_idx`.
seen[expected_idx] = true;
// Next a search is performed to determine whether
// this edge is a dead end or leads to the sink.
//
// `expected_match[expected_idx].is_none()` means that there is residual flow
// from expected node at index expected_idx to the sink, so we
// can use that to finish this flow path and return success.
//
// Otherwise, we look for a residual flow starting from
// `expected_match[expected_idx].unwrap()` by calling
// ourselves recursively to see if this ultimately leads to
// sink.
if expected_match[expected_idx].is_none()
|| self.try_augment(
expected_match[expected_idx].unwrap(),
seen,
actual_match,
expected_match,
)
{
// We found a residual flow from source to sink. We thus need to add the new
// edge to the current flow.
// Note: this also remove the potential flow that existed by overwriting the
// value in the `expected_match` and `actual_match`.
expected_match[expected_idx] = Some(actual_idx);
actual_match[actual_idx] = Some(expected_idx);
return true;
}
}
false
}
}
/// The list of elements that do not match any element in the corresponding
/// set.
/// These lists are represented as fixed sized bit set to avoid
/// allocation.
/// TODO(bjacotg) Use BitArr!(for N) once generic_const_exprs is stable.
struct UnmatchableElements<const N: usize> {
unmatchable_actual: Vec<bool>,
unmatchable_expected: [bool; N],
}
impl<const N: usize> UnmatchableElements<N> {
fn has_unmatchable_elements(&self) -> bool {
self.unmatchable_actual.iter().any(|b| *b)
|| self.unmatchable_expected.iter().any(|b| *b)
}
fn get_explanation(&self) -> Option<Description> {
let unmatchable_actual = self.unmatchable_actual();
let actual_idx = unmatchable_actual
.iter()
.map(|idx| format!("#{}", idx))
.collect::<Vec<_>>()
.join(", ");
let unmatchable_expected = self.unmatchable_expected();
let expected_idx = unmatchable_expected
.iter()
.map(|idx| format!("#{}", idx))
.collect::<Vec<_>>()
.join(", ");
match (unmatchable_actual.len(), unmatchable_expected.len()) {
(0, 0) => None,
(1, 0) => {
Some(format!("whose element {actual_idx} does not match any expected elements").into())
}
(_, 0) => {
Some(format!("whose elements {actual_idx} do not match any expected elements",).into())
}
(0, 1) => Some(format!(
"which has no element matching the expected element {expected_idx}"
).into()),
(0, _) => Some(format!(
"which has no elements matching the expected elements {expected_idx}"
).into()),
(1, 1) => Some(format!(
"whose element {actual_idx} does not match any expected elements and no elements match the expected element {expected_idx}"
).into()),
(_, 1) => Some(format!(
"whose elements {actual_idx} do not match any expected elements and no elements match the expected element {expected_idx}"
).into()),
(1, _) => Some(format!(
"whose element {actual_idx} does not match any expected elements and no elements match the expected elements {expected_idx}"
).into()),
(_, _) => Some(format!(
"whose elements {actual_idx} do not match any expected elements and no elements match the expected elements {expected_idx}"
).into()),
}
}
fn unmatchable_actual(&self) -> Vec<usize> {
self.unmatchable_actual
.iter()
.enumerate()
.filter_map(|(idx, b)| if *b { Some(idx) } else { None })
.collect()
}
fn unmatchable_expected(&self) -> Vec<usize> {
self.unmatchable_expected
.iter()
.enumerate()
.filter_map(|(idx, b)| if *b { Some(idx) } else { None })
.collect()
}
}
/// The representation of a match between actual and expected.
/// The value at idx represents to which expected the actual at idx is
/// matched with. For example, `BestMatch([Some(0), None, Some(1)])`
/// means:
/// * The 0th element in actual matches the 0th element in expected.
/// * The 1st element in actual does not match.
/// * The 2nd element in actual matches the 1st element in expected.
struct BestMatch<const N: usize>(Vec<Option<usize>>);
impl<const N: usize> BestMatch<N> {
fn is_full_match(&self) -> bool {
self.0.iter().all(|o| o.is_some())
}
fn is_subset_match(&self) -> bool {
self.is_full_match()
}
fn is_superset_match(&self) -> bool {
self.get_unmatched_expected().is_empty()
}
fn get_matches(&self) -> impl Iterator<Item = (usize, usize)> + '_ {
self.0.iter().enumerate().filter_map(|(actual_idx, maybe_expected_idx)| {
maybe_expected_idx.map(|expected_idx| (actual_idx, expected_idx))
})
}
fn get_unmatched_actual(&self) -> impl Iterator<Item = usize> + '_ {
self.0
.iter()
.enumerate()
.filter(|&(_, o)| o.is_none())
.map(|(actual_idx, _)| actual_idx)
}
fn get_unmatched_expected(&self) -> Vec<usize> {
let matched_expected: HashSet<_> = self.0.iter().flatten().collect();
(0..N).filter(|expected_idx| !matched_expected.contains(expected_idx)).collect()
}
fn get_explanation<
'a,
T: Debug + Copy,
ContainerT: Debug + Copy + IntoIterator<Item = T>,
>(
&self,
actual: ContainerT,
expected: &[Box<dyn Matcher<T> + 'a>; N],
requirements: Requirements,
) -> Option<Description> {
let actual: Vec<_> = actual.into_iter().collect();
if self.is_full_match() {
return None;
}
let mut error_message =
format!("which does not have a {requirements} match with the expected elements.");
error_message.push_str("\n The best match found was: ");
let matches = self.get_matches().map(|(actual_idx, expected_idx)|{
format!(
"Actual element {:?} at index {actual_idx} matched expected element `{}` at index {expected_idx}.",
actual[actual_idx],
expected[expected_idx].describe(MatcherResult::Match),
)});
let unmatched_actual = self.get_unmatched_actual().map(|actual_idx| {
format!(
"Actual element {:#?} at index {actual_idx} did not match any remaining expected element.",
actual[actual_idx]
)
});
let unmatched_expected = self.get_unmatched_expected().into_iter().map(|expected_idx|{format!(
"Expected element `{}` at index {expected_idx} did not match any remaining actual element.",
expected[expected_idx].describe(MatcherResult::Match)
)});
let best_match = matches
.chain(unmatched_actual)
.chain(unmatched_expected)
.collect::<Description>()
.indent();
Some(format!(
"which does not have a {requirements} match with the expected elements. The best match found was:\n{best_match}"
).into())
}
}
}
#[cfg(test)]
mod tests {
use crate::matcher::MatcherResult;
use crate::prelude::*;
use indoc::indoc;
use std::collections::HashMap;
#[test]
fn has_correct_description_for_map() -> Result<()> {
// UnorderedElementsAreMatcher maintains references to the matchers, so the
// constituent matchers must live longer. Inside a verify_that! macro, the
// compiler takes care of that, but when the matcher is created separately,
// we must create the constitute matchers separately so that they
// aren't dropped too early.
let matchers = ((eq(&2), eq(&"Two")), (eq(&1), eq(&"One")), (eq(&3), eq(&"Three")));
let matcher = unordered_elements_are![
(matchers.0.0, matchers.0.1),
(matchers.1.0, matchers.1.1),
(matchers.2.0, matchers.2.1)
];
verify_that!(
Matcher::<&HashMap<i32, String>>::describe(&matcher, MatcherResult::Match),
displays_as(eq(indoc!(
"
contains elements matching in any order:
0. is a tuple whose values respectively match:
is equal to 2
is equal to \"Two\"
1. is a tuple whose values respectively match:
is equal to 1
is equal to \"One\"
2. is a tuple whose values respectively match:
is equal to 3
is equal to \"Three\""
)))
)
}
#[test]
fn unordered_elements_are_description_no_full_match_with_map() -> Result<()> {
// UnorderedElementsAreMatcher maintains references to the matchers, so the
// constituent matchers must live longer. Inside a verify_that! macro, the
// compiler takes care of that, but when the matcher is created separately,
// we must create the constitute matchers separately so that they
// aren't dropped too early.
let value: HashMap<u32, u32> = HashMap::from_iter([(0, 1), (1, 1), (2, 2)]);
let matchers = ((anything(), eq(&1)), (anything(), eq(&2)), (anything(), eq(&2)));
let matcher = unordered_elements_are![
(matchers.0.0, matchers.0.1),
(matchers.1.0, matchers.1.1),
(matchers.2.0, matchers.2.1),
];
verify_that!(
matcher.explain_match(&value),
all![
displays_as(contains_regex(
"Actual element \\(2, 2\\) at index [0-2] matched expected element `is a tuple whose values respectively match:\n is anything\n is equal to 2` at index [0-2]."
)),
displays_as(contains_regex(
"Actual element \\(\n [0-1],\n [0-1],\n \\) at index [0-2] did not match any remaining expected element."
)),
displays_as(contains_substring(
"Expected element `is a tuple whose values respectively match:\n is anything\n is equal to 2` at index 2 did not match any remaining actual element."
))
]
)
}
}