Migrate Microsoft.DotNet.ApiCompat.Tests to MSTest.Sdk on MTP by Evangelink · Pull Request #54724 · dotnet/sdk

Evangelink · 2026-06-11T19:28:55Z

Same pattern as #54723. This project's single test file (RegexStringTransformerTests.cs) only uses xUnit Fact/Assert.Equal — no Microsoft.NET.TestFramework types — so the TestFramework ProjectReference can be dropped and the project switched to MSTest.Sdk in one self-contained change.

Changes

test/Microsoft.DotNet.ApiCompat.Tests/Microsoft.DotNet.ApiCompat.Tests.csproj
- Use Sdk="MSTest.Sdk", set UseMSTestSdk=true.
- Drop ProjectReference to Microsoft.NET.TestFramework (unused).
- Drop OutputType=Exe (MSTest.Sdk handles it).
- Add Microsoft.VisualStudio.TestTools.UnitTesting global using.
test/Microsoft.DotNet.ApiCompat.Tests/RegexStringTransformerTests.cs: [Fact] → [TestMethod], add [TestClass], Assert.Equal → Assert.AreEqual.

Verification

✅ 5/5 tests pass on MTP (~250 ms).

Merge ordering

Stacks on top of #54723 which stacks on #54722. Once both merge, this PR will rebase cleanly onto main.

Relates to #52914.

Copilot

Pull request overview

This PR migrates several test projects from xUnit-based defaults to MSTest.Sdk (running on Microsoft.Testing.Platform) by introducing a per-project opt-out switch (UseMSTestSdk=true) and mechanically converting affected tests/asserters. It also adjusts dotnet-watch.Tests to host Aspire-related integration tests that still depend on Microsoft.NET.TestFramework.

Changes:

Add MSTest.Sdk to global.json and gate the test-folder xUnit defaults in test/Directory.Build.targets behind UseMSTestSdk.
Convert multiple unit test projects to Sdk="MSTest.Sdk" and update test attributes/assertions accordingly (including a local AssertEx helper where needed).
Move/enable Aspire integration-test support in dotnet-watch.Tests via additional references and InternalsVisibleTo.

Show a summary per file

File	Description
global.json	Pins `MSTest.Sdk` MSBuild SDK version so `Sdk="MSTest.Sdk"` projects restore/build.
test/Directory.Build.targets	Gates xUnit-specific defaults/usings behind `UseMSTestSdk` to allow per-project MSTest adoption.
test/Microsoft.DotNet.ApiCompat.Tests/Microsoft.DotNet.ApiCompat.Tests.csproj	Switches ApiCompat test project to `MSTest.Sdk` and adds MSTest global using.
test/Microsoft.DotNet.ApiCompat.Tests/RegexStringTransformerTests.cs	Converts xUnit `[Fact]`/`Assert.Equal` to MSTest `[TestMethod]`/`Assert.AreEqual`.
test/containerize.UnitTests/containerize.UnitTests.csproj	Switches to `MSTest.Sdk`, opts out of xUnit defaults, removes `Microsoft.NET.TestFramework` reference.
test/containerize.UnitTests/ParserTests.cs	Converts xUnit tests to MSTest equivalents (`[DataRow]`, `Assert.AreEqual`, etc.).
test/Microsoft.DotNet.HotReload.Watch.Aspire.Tests/Microsoft.DotNet.HotReload.Watch.Aspire.Tests.csproj	Switches the Aspire unit test project to `MSTest.Sdk`, drops xUnit-coupled test utilities, adds assertion packages/usings.
test/Microsoft.DotNet.HotReload.Watch.Aspire.Tests/AssertEx.cs	Adds a small local assertion helper to avoid depending on xUnit-coupled shared test utilities.
test/Microsoft.DotNet.HotReload.Watch.Aspire.Tests/AspireServerLauncherCliTests.cs	Converts xUnit tests to MSTest (`[TestClass]`, `[TestMethod]`, MSTest asserts).
test/Microsoft.DotNet.HotReload.Watch.Aspire.Tests/AspireResourceLauncherCliTests.cs	Converts xUnit tests to MSTest, including theory/data conversion to `[DataRow]`.
test/Microsoft.DotNet.HotReload.Watch.Aspire.Tests/AspireHostLauncherTests.cs	Converts xUnit tests to MSTest and updates asserts accordingly.
test/Microsoft.DotNet.HotReload.Watch.Aspire.Tests/AspireHostLauncherCliTests.cs	Converts xUnit tests to MSTest and updates asserts accordingly.
src/Dotnet.Watch/Watch.Aspire/Properties/AssemblyInfo.cs	Grants `InternalsVisibleTo` for `dotnet-watch.Tests` to support moved integration tests.
test/dotnet-watch.Tests/dotnet-watch.Tests.csproj	Adds a reference to `Watch.Aspire` for Aspire integration tests that execute the launcher.
test/dotnet-watch.Tests/Aspire/PipeUtilities.cs	Adds helper for reading status events from a named pipe in integration tests.
test/dotnet-watch.Tests/Aspire/AspireLauncherIntegrationTests.cs	Renames the Aspire launcher test class to reflect its integration-test nature.

Copilot's findings

Files reviewed: 15/16 changed files
Comments generated: 1

… on MTP Same pattern as previous migrations. None of the 6 test files used any Microsoft.NET.TestFramework types - only xUnit primitives - so the TestFramework ProjectReference can be dropped and the project switched to MSTest.Sdk in one self-contained change. Changes: * test/Microsoft.AspNetCore.Watch.BrowserRefresh.Tests/csproj: - Use Sdk="MSTest.Sdk", set UseMSTestSdk=true. - Drop ProjectReference to Microsoft.NET.TestFramework (unused). - Drop OutputType=Exe (MSTest.Sdk handles it). - Add Microsoft.VisualStudio.TestTools.UnitTesting global using. * 6 test files: xUnit -> MSTest mechanical conversion plus targeted fixes: - [Fact]/[Theory] -> [TestMethod], [InlineData] -> [DataRow], add [TestClass]. - Assert.True/False/Null/NotNull/Empty/NotEmpty/Equal/NotEqual -> IsTrue/IsFalse/IsNull/IsNotNull/IsEmpty/IsNotEmpty/AreEqual/AreNotEqual. - Assert.Single(x) -> Assert.HasCount(1, x). - String Assert.Contains(needle, haystack) -> StringAssert.Contains(haystack, needle) (xUnit and MSTest argument orders are reversed). - One Assert.DoesNotContain(needle, str) -> Assert.IsFalse(str.Contains(needle)). - Assert.Collection in BrowserScriptMiddlewareTest expanded to inline Assert.HasCount + indexed AreEqual checks. - Assert.ThrowsAsync<T> -> Assert.ThrowsExactlyAsync<T>. - Assert.AreEqual on byte[]/int[] -> Assert.AreSequenceEqual (MSTEST0065: MSTest does not do element-wise equality on collections; the analyzer catches a real semantic difference vs xUnit). - StringValues (Microsoft.Extensions.Primitives) ambiguity with Assert.AreEqual<T> resolved by calling .ToString() at 5 call sites. - xUnit v3 TestContext.Current.CancellationToken -> CancellationToken.None (MSTest's TestContext.Current is experimental; tests do not actually require test-cancellation propagation). Verification: 110/110 tests pass on MTP in ~480 ms. Stacks on dotnet#54724 which stacks on dotnet#54723 which stacks on dotnet#54722. Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Evangelink · 2026-06-11T20:21:43Z

Re-validated this PR against the new migrate-xunit-to-mstest skill landed in #54727 and bumped MSTest.Sdk to 4.3.0-preview.26311.10 (latest internal preview) via the pathfinder.

Changes applied in the latest push on this branch:
Re-validated; no changes required.

Other gotchas reviewed (no changes needed here):

Assert.AreEqual argument order — verified (expected, actual) throughout, matching the xUnit Assert.Equal(expected, actual) original.
CollectionAssert argument order — verified.
Assert.ThrowsExactly<T> vs Assert.Throws<T> semantics — verified (xUnit Throws<T> is exact; MSTest's same-named API is inclusive, so the migration uses ThrowsExactly<T>).
IsInstanceOfType<T> vs IsExactInstanceOfType<T> — see dotnet/skills#755 for the cheatsheet update we filed upstream.

Tests still pass locally on the bumped MSTest.Sdk.

… on MTP Same pattern as previous migrations. None of the 6 test files used any Microsoft.NET.TestFramework types - only xUnit primitives - so the TestFramework ProjectReference can be dropped and the project switched to MSTest.Sdk in one self-contained change. Changes: * test/Microsoft.AspNetCore.Watch.BrowserRefresh.Tests/csproj: - Use Sdk="MSTest.Sdk", set UseMSTestSdk=true. - Drop ProjectReference to Microsoft.NET.TestFramework (unused). - Drop OutputType=Exe (MSTest.Sdk handles it). - Add Microsoft.VisualStudio.TestTools.UnitTesting global using. * 6 test files: xUnit -> MSTest mechanical conversion plus targeted fixes: - [Fact]/[Theory] -> [TestMethod], [InlineData] -> [DataRow], add [TestClass]. - Assert.True/False/Null/NotNull/Empty/NotEmpty/Equal/NotEqual -> IsTrue/IsFalse/IsNull/IsNotNull/IsEmpty/IsNotEmpty/AreEqual/AreNotEqual. - Assert.Single(x) -> Assert.HasCount(1, x). - String Assert.Contains(needle, haystack) -> StringAssert.Contains(haystack, needle) (xUnit and MSTest argument orders are reversed). - One Assert.DoesNotContain(needle, str) -> Assert.IsFalse(str.Contains(needle)). - Assert.Collection in BrowserScriptMiddlewareTest expanded to inline Assert.HasCount + indexed AreEqual checks. - Assert.ThrowsAsync<T> -> Assert.ThrowsExactlyAsync<T>. - Assert.AreEqual on byte[]/int[] -> Assert.AreSequenceEqual (MSTEST0065: MSTest does not do element-wise equality on collections; the analyzer catches a real semantic difference vs xUnit). - StringValues (Microsoft.Extensions.Primitives) ambiguity with Assert.AreEqual<T> resolved by calling .ToString() at 5 call sites. - xUnit v3 TestContext.Current.CancellationToken -> CancellationToken.None (MSTest's TestContext.Current is experimental; tests do not actually require test-cancellation propagation). Verification: 110/110 tests pass on MTP in ~480 ms. Stacks on dotnet#54724 which stacks on dotnet#54723 which stacks on dotnet#54722. Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Imports the migrate-xunit-to-mstest skill from dotnet/skills@main (plugins/dotnet-test/skills/migrate-xunit-to-mstest) into this repo so the xUnit -> MSTest migration that's currently in progress (#54722, #54723, #54724, #54725, #54726) has a documented, repeatable procedure that contributors and agents can follow consistently. Files added (verbatim from upstream): - .github/skills/migrate-xunit-to-mstest/SKILL.md - .github/skills/migrate-xunit-to-mstest/references/mapping-cheatsheet.md Note: SKILL.md is 546 lines, slightly above the 500-line "Progressive Disclosure" guideline checked by .github/skills/ValidateSkill.cs. The validator is advisory (not CI-enforced) and we are intentionally mirroring the upstream content verbatim to keep future syncs trivial. Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Evangelink · 2026-06-12T11:31:00Z

Replaced the manual <UseMSTestSdk>true</UseMSTestSdk> opt-in with the property MSTest.Sdk already sets for us: UsingMSTestSdk. Since MSTest.Sdk's Sdk.props runs before Microsoft.NET.Sdk.props and test/Directory.Build.targets is imported at the bottom of evaluation, the property is in scope wherever we need it — no per-project knob required.

Also refreshed the related comments in XUnitPublish.targets / XUnitRunner.targets and renamed the intermediate _UseMSTestSdk MSBuild property to _UsingMSTestSdk for clarity. (Thanks @Evangelink for the catch.)

Evangelink · 2026-06-12T11:37:49Z

Made --report-trx conditional on Microsoft.Testing.Extensions.TrxReport actually being loaded. MSTest.Sdk enables that extension by default via EnableMicrosoftTestingExtensionsTrxReport=true for the Default / AllMicrosoft profiles, but other MTP hosts (xUnit v3 MTP, MSTest.Sdk with TestingExtensionsProfile=None, etc.) do not — passing --report-trx there fails with 'unknown argument'.

The new GetTrxReportEnabled target queries that property; XUnitRunner.targets propagates it as EnableTrxReport metadata, and SDKCustomCreateXUnitWorkItemsWithTestExclusion only emits the flag when it's true. No behavioural change for the current PRs since all migrated projects are MSTest.Sdk-based, but the dispatcher is now forward-safe.

(Applied to all 9 stacked PRs since they share these plumbing files.)

Evangelink · 2026-06-12T11:37:52Z

Replaced the custom <UseMSTestSdk> opt-in property with the built-in UsingMSTestSdk property that MSTest.Sdk already sets in its Sdk.props before Directory.Build.props is evaluated. This drops a redundant declaration in every migrated csproj and just reads what the SDK already publishes.

Evangelink · 2026-06-12T12:09:45Z

Round 3: moved FluentAssertions Using and AwesomeAssertions PackageReference to test/Directory.Build.targets.

The Using is now global for any test project ('$(IsTestProject)' == 'true' OR '$(UsingMSTestSdk)' == 'true'). The PackageReference is added for MSTest.Sdk projects only — xUnit projects already get it transitively via the Microsoft.NET.TestFramework project reference.

Deviation from your literal suggestion: I left the Microsoft.NET.TestFramework.* Usings and Xunit Using gated on UsingMSTestSdk != true. Moving them unconditional would also require a global <ProjectReference Include="Microsoft.NET.TestFramework" /> (otherwise MSTest projects would fail with CS0246), which would drag xunit.v3.assert and other xUnit pieces into the MSTest projects. Happy to apply the broader change (with a global ProjectRef) if you'd prefer.

…n MTP This is a pathfinder PR for migrating the test suite to MSTest on Microsoft.Testing.Platform (MTP). Microsoft.DotNet.HotReload.Watch.Aspire.Tests was chosen because it has no dependency on the shared Microsoft.NET.TestFramework (which is xUnit-coupled and referenced by ~57 of 78 test projects), so it can migrate in isolation without unblocking dependents first. Changes: * global.json: add MSTest.Sdk 4.3.0-preview.26307.5 to msbuild-sdks. * test/Directory.Build.targets: gate the xUnit defaults (TestRunnerName=XUnitV3, Using Include=Xunit, etc.) behind $(UseMSTestSdk) != true, so MSTest.Sdk projects opt out cleanly. * test/Microsoft.DotNet.HotReload.Watch.Aspire.Tests: - csproj now uses Sdk="MSTest.Sdk", sets UseMSTestSdk=true, references AwesomeAssertions and only the Watch.Aspire project. MTP is on by default via MSTest.Sdk (EnableMSTestRunner + TestingPlatformDotnetTestSupport). - All 4 unit-test files converted from xUnit to MSTest attributes/asserts ([Fact]/[Theory] -> [TestMethod]/[DataRow], Assert.* equivalents, Assert.IsInstanceOfType<T>, Assert.HasCount, Assert.IsEmpty). - Local AssertEx.SequenceEqual<T> helper replaces the xUnit-coupled one from HotReload.Test.Utilities. * Move the 2 integration tests (AspireLauncherTests + PipeUtilities) to test/dotnet-watch.Tests/Aspire/ so the Aspire.Tests project stays a pure MSTest unit-test project. They keep xUnit because they depend on WatchSdkTest, WatchableApp, [PlatformSpecificFact], ITestOutputHelper and TestAssets from Microsoft.NET.TestFramework. AspireLauncherTests was renamed to AspireLauncherIntegrationTests to reflect its new role. * src/Dotnet.Watch/Watch.Aspire/Properties/AssemblyInfo.cs: grant InternalsVisibleTo to dotnet-watch.Tests (needed by PipeUtilities, which uses internal WatchStatusEvent). * test/dotnet-watch.Tests/dotnet-watch.Tests.csproj: add ProjectReference to Watch.Aspire (ExcludeAssets=Runtime) so the moved integration tests compile. Verification: * Microsoft.DotNet.HotReload.Watch.Aspire.Tests builds with MSTest.Sdk and all 58 unit tests pass under MTP (705 ms). * test/dotnet-watch.Tests builds successfully with the moved files. Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

- Bumps MSTest.Sdk to the latest internal preview to pick up the newest 4.3 assertion APIs (Assert.ContainsSingle, Assert.Contains for strings with the more natural (needle, haystack) signature, etc.). - Applies the assertion mapping flagged by the migrate-xunit-to-mstest skill in this repo (.github/skills/migrate-xunit-to-mstest, PR dotnet#54727): Assert.HasCount(1, x) -> Assert.ContainsSingle(x) (one occurrence in AspireResourceLauncherCliTests.cs) Verified: 58/58 tests still pass. Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

…parity Per reviewer feedback: MSTest 4.1.0+ exposes Assert.IsExactInstanceOfType<T>(value) which returns T and enforces exact-type semantics -- the proper equivalent of xUnit's Assert.IsType<T>(x). Assert.IsInstanceOfType<T> is the equivalent of xUnit's Assert.IsAssignableFrom<T> (assignable, not exact), which would be a silent semantic regression for the IsType<T> originals. All 39 occurrences across AspireHostLauncherCliTests.cs, AspireResourceLauncherCliTests.cs, AspireServerLauncherCliTests.cs, and AspireLauncherIntegrationTests.cs were originally Assert.IsType<T> in xUnit (verified against main), so all 39 are flipped to Assert.IsExactInstanceOfType<T>. Note: the migrate-xunit-to-mstest skill cheatsheet at .github/skills/migrate-xunit-to-mstest/references/mapping-cheatsheet.md recommends `Assert.IsInstanceOfType<T>` plus an extra typeof-check for exact-type semantics; that guidance predates IsExactInstanceOfType being available. Follow-up upstream (dotnet/skills) suggested. Verified: 58/58 Aspire tests still pass; dotnet-watch.Tests builds clean. Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Evangelink · 2026-06-13T18:22:35Z

/azp run dotnet-sdk-public-ci

azure-pipelines · 2026-06-13T18:22:46Z