Add BeSupersetOf, BeProperSubsetOf and BeProperSupersetOf collection assertions - #3271
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Pull request overview
Adds new set-containment style collection assertions to FluentAssertions (BeSupersetOf, BeProperSubsetOf, BeProperSupersetOf) and factors shared subset/containment logic to reduce duplication, along with tests, docs, and updated API approval baselines.
Changes:
- Added
BeSupersetOf,BeProperSubsetOf, andBeProperSupersetOftoGenericCollectionAssertions. - Extracted shared helpers (
AssertSubsetOf,AssertContainment) and introducedConvertOrCastToSetfor set-based checks. - Added/ported specs and updated collection docs + release notes + API approval baselines.
Reviewed changes
Copilot reviewed 11 out of 12 changed files in this pull request and generated 4 comments.
Show a summary per file
| File | Description |
|---|---|
| Tests/FluentAssertions.Specs/Collections/CollectionAssertionSpecs.BeSupersetOf.cs | New specs covering BeSupersetOf success/failure and scope behavior. |
| Tests/FluentAssertions.Specs/Collections/CollectionAssertionSpecs.BeProperSupersetOf.cs | New specs covering BeProperSupersetOf, including equivalence and duplicates scenarios. |
| Tests/FluentAssertions.Specs/Collections/CollectionAssertionSpecs.BeProperSubsetOf.cs | New specs covering BeProperSubsetOf, including equivalence and null/empty scenarios. |
| Tests/Approval.Tests/ApprovedApi/FluentAssertions/netstandard2.1.verified.txt | API baseline updated for new assertions. |
| Tests/Approval.Tests/ApprovedApi/FluentAssertions/netstandard2.0.verified.txt | API baseline updated for new assertions. |
| Tests/Approval.Tests/ApprovedApi/FluentAssertions/net6.0.verified.txt | API baseline updated for new assertions. |
| Tests/Approval.Tests/ApprovedApi/FluentAssertions/net47.verified.txt | API baseline updated for new assertions. |
| Src/FluentAssertions/Common/EnumerableExtensions.cs | Adds internal ConvertOrCastToSet helper for set-based operations. |
| Src/FluentAssertions/Collections/GenericCollectionAssertions.cs | Implements the new assertions and refactors subset/containment logic into helpers. |
| docs/_pages/releases.md | Adds an “Unreleased” note about the new collection assertions. |
| docs/_pages/collections.md | Documents usage examples for the new assertions. |
| .gitignore | Fixes .junie/memory/ ignore entry and adds .nuke/temp. |
Suppressed comments (1)
Tests/FluentAssertions.Specs/Collections/CollectionAssertionSpecs.BeProperSupersetOf.cs:68
- Test name says "proper subset" but this spec is for
BeProperSupersetOf. Rename to "proper superset" to match the behavior under test.
public void A_collection_with_duplicates_is_not_a_proper_subset_of_another_with_duplicates()
…assertions Ports the work originally submitted in PR fluentassertions#2432 by @Meir017, adapted to the current AssertionChain-based assertion API. The original PR could not be reopened because its base branch (develop) no longer exists. - Add ConvertOrCastToSet extension to EnumerableExtensions - Extract AssertSubsetOf and AssertContainment helpers in GenericCollectionAssertions to share logic with the new assertions - Add BeSupersetOf, BeProperSubsetOf and BeProperSupersetOf methods - Add spec tests ported from the original PR - Update collections.md docs and releases.md Co-authored-by: Meir017 <Meir017@users.noreply.github.com> Co-authored-by: Copilot App <223556219+Copilot@users.noreply.github.com>
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Pull request overview
Copilot reviewed 11 out of 12 changed files in this pull request and generated no new comments.
Suppressed comments (2)
Tests/FluentAssertions.Specs/Collections/CollectionAssertionSpecs.BeProperSubsetOf.cs:54
- This test name says the collection "has extra items", but the Arrange section is asserting that duplicates do not make a collection a proper subset when the distinct items are equivalent to the superset. Rename the test to describe equivalence rather than extra elements.
public void A_collection_with_all_items_and_duplicates_of_a_superset_but_has_extra_items_is_not_a_proper_subset()
Tests/FluentAssertions.Specs/Collections/CollectionAssertionSpecs.BeProperSubsetOf.cs:38
- This test name says the collection "has extra items", but the Arrange section uses two collections with the same distinct items (they're equivalent as sets). Rename the test to reflect that the failure is due to equivalence (not extra elements).
This issue also appears on line 54 of the same file.
public void A_collection_with_all_items_of_a_superset_but_has_extra_items_is_not_a_proper_subset()
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We have an inconsistency in whether we allow the expectation to be empty.
E.g. when both subject and expectation are empty we get the following outcomes.
BeSubsetOf: passesBeProperSubsetOf: Expected subset to be a proper subset of {empty}, but items {empty} are equivalent to the superset {empty}BeSupersetOf: ArgumentException : Cannot verify containment against an empty collection (Parameter 'expected')BeProperSupersetOf: ArgumentException : Cannot verify containment against an empty collection (Parameter 'expected')
I think the superset APIs should allow the expectation to be empty.
See e.g. the discussion in #2143
Addresses jnyrup's review feedback on fluentassertions#3271: BeSupersetOf and BeProperSupersetOf previously threw ArgumentException when the expected collection was empty, which was inconsistent with BeSubsetOf/BeProperSubsetOf (an empty set is trivially a subset of everything, so a superset check against an empty expectation should never throw). - Split the empty-argument guard out of AssertContainment behind an allowEmptyExpectation flag so Contain keeps its existing behavior while BeSupersetOf/BeProperSupersetOf now evaluate normally instead of throwing. - BeSupersetOf(empty) now always passes. - BeProperSupersetOf(empty) now passes when the subject is non-empty and fails (not throws) when the subject is also empty, since two empty collections are identical rather than a proper superset. - Rewrote the XML doc comments for BeSubsetOf/BeSupersetOf/ BeProperSubsetOf/BeProperSupersetOf in plain language, removing set notation and math jargon, and dropped the now-inaccurate ArgumentException doc entries for the superset methods. - Wrapped single-element expectations in curly braces in the new superset failure messages, matching how multi-element collections are already rendered. - Added missing spec coverage: null expectation, both empty, and equal-non-empty collections for BeSupersetOf, BeProperSubsetOf and BeProperSupersetOf. - Updated docs/_pages/collections.md and releases.md. Co-authored-by: Copilot App <223556219+Copilot@users.noreply.github.com>
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Good points indeed. I think I have all scenarios covered now. |
…ainment Fixes a CI failure (StackTraceHiddenSpecs.Non_public_methods_in_annotable_classes_are_hidden) surfaced after modifying these private helper methods. Co-authored-by: Copilot App <223556219+Copilot@users.noreply.github.com>
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Co-authored-by: Copilot App <223556219+Copilot@users.noreply.github.com>
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Updated [FluentAssertions](https://github.com/fluentassertions/fluentassertions) from 8.10.0 to 8.11.0. <details> <summary>Release notes</summary> _Sourced from [FluentAssertions's releases](https://github.com/fluentassertions/fluentassertions/releases)._ ## 8.11.0 <!-- Release notes generated using configuration in .github/release.yml at main --> ## What's Changed ### New features * Add `ThatSatisfy` for methods and properties by @jnyrup in fluentassertions/fluentassertions#3257 * Add BeSupersetOf, BeProperSubsetOf and BeProperSupersetOf collection assertions by @dennisdoomen in fluentassertions/fluentassertions#3271 * Add BeJsonSerializable round-trip assertions by @dennisdoomen in fluentassertions/fluentassertions#3293 * Support asserting on delegates that return a value task by @dennisdoomen in fluentassertions/fluentassertions#3301 ### Improvements * BeEmpty for IEnumerable<T> assertions now lists the first 10 items in… by @Xceed-DelvaJB in fluentassertions/fluentassertions#3198 * Clean-up the stack trace further by @jnyrup in fluentassertions/fluentassertions#3290 * Add HaveLineCount()/NotHaveLineCount() and ContainLine()/NotContainLine() to StringAssertions by @dennisdoomen in fluentassertions/fluentassertions#3297 * Add public ValueTypeAssertions<TSubject, TAssertions> base class by @dennisdoomen in fluentassertions/fluentassertions#3308 ### Fixes * Fix JsonNodeAssertions.HaveProperty/NotHaveProperty for properties with explicit null values by @dennisdoomen with @Copilot in fluentassertions/fluentassertions#3282 * Fix exception on `HaveProperty` on `JsonArray` by @jnyrup in fluentassertions/fluentassertions#3295 * Fix potential NREs when using AssertionScope (#3178) by @dennisdoomen in fluentassertions/fluentassertions#3323 ### Documentation * Fix typos by @jnyrup in fluentassertions/fluentassertions#3310 * Fix typo in exceptions page by @jpgomezv in fluentassertions/fluentassertions#3317 ### Others * Simplify GetMinValue/GetMaxValue by @jnyrup in fluentassertions/fluentassertions#3210 * Revert "Bump coverlet.collector from 6.0.4 to 8.0.1" by @jnyrup in fluentassertions/fluentassertions#3218 * Update nugets by @jnyrup in fluentassertions/fluentassertions#3226 * Convert the build pipeline from Nuke to Fallout by @dennisdoomen in fluentassertions/fluentassertions#3234 * Expose ShouldThrowOnCyclicReference on IEquivalencyValidationContext by @dennisdoomen in fluentassertions/fluentassertions#3242 * Prevent pwn-request RCE via the Qodana workflow by @dennisdoomen in fluentassertions/fluentassertions#3217 * Harden NPM install by @jnyrup in fluentassertions/fluentassertions#3258 * Pin System.Security.Cryptography.Xml to patched version to fix build restore failures by @dennisdoomen in fluentassertions/fluentassertions#3283 * Exclude dependabot PRs from auto-generated release notes by @dennisdoomen in fluentassertions/fluentassertions#3294 * Fix Qodana PR scans failing on pull requests from forks by @dennisdoomen in fluentassertions/fluentassertions#3299 * Cancel duplicate CI runs when a push triggers both push and pull_request events by @dennisdoomen in fluentassertions/fluentassertions#3298 * Fix Qodana-flagged possible multiple enumeration and unused auto-property warnings by @dennisdoomen in fluentassertions/fluentassertions#3300 * Document lessons learned from #3291 in agents.md by @dennisdoomen in fluentassertions/fluentassertions#3307 * Pin SDK to workaround 10.0.400 by @jnyrup in fluentassertions/fluentassertions#3309 * Stop the Build workflow from running twice on same-repo PRs by @dennisdoomen in fluentassertions/fluentassertions#3311 * Update NuGet.Frameworks to workaround Fallout issue by @jnyrup in fluentassertions/fluentassertions#3318 * Prefer Count > 0 over Any() by @jnyrup in fluentassertions/fluentassertions#3321 * Correct the arguments passed to `string.Format` on failure by @jnyrup in fluentassertions/fluentassertions#3325 * Migrate xunit v3 test projects off the VSTest pipeline by @dennisdoomen in fluentassertions/fluentassertions#3320 * Include PackageGuard risk report and SBOM in pipeline by @dennisdoomen in fluentassertions/fluentassertions#3324 ## New Contributors * @jpgomezv made their first contribution in fluentassertions/fluentassertions#3317 **Full Changelog**: fluentassertions/fluentassertions@8.10.0...8.11.0 Commits viewable in [compare view](fluentassertions/fluentassertions@8.10.0...8.11.0). </details> Signed-off-by: dependabot[bot] <support@github.com> Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
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Ports the work originally submitted in #2432 by @Meir017 (
Meir017:feature/api-subset-and-superset), which added BeSupersetOf, BeProperSubsetOf and BeProperSupersetOf collection assertions.That PR could not be reopened because its base branch (develop) has since been deleted/renamed to main, so this PR recreates the same feature against current main.
What's included
Closes #2432
Resolves #2363
All credit for the original design and implementation goes to @Meir017.
Empty-collection behavior
Following up on review feedback, here's how each assertion behaves when the expected collection is empty:
BeSubsetOfBeSubsetOfBeProperSubsetOfBeSupersetOfBeProperSupersetOfBeProperSupersetOfnullArgumentNullExceptionBeSupersetOfandBeProperSupersetOfpreviously threwArgumentExceptionfor an empty expectation instead of evaluating normally - that's now fixed so they behave consistently withBeSubsetOf/BeProperSubsetOf.