Switch the Coverage Engine to Microsoft.Testing.Extensions.CodeCoverage

.github/workflows/publish-release.yml

@@ -42,8 +42,10 @@ jobs:
       ref_name: ${{ github.ref_name }}
 
   # The same gate the PR runs, on the branch tip, running only when a publish will happen. Still this repo's
-  # own validate-task.yml rather than the hub's: the hub's unit-test step is the VSTest invocation that
-  # Microsoft.Testing.Platform rejects on the .NET 10 SDK (ptr727/ProjectTemplate#1088).
+  # own validate-task.yml rather than the hub's. The unit-test step matches the hub's now that
+  # ptr727/ProjectTemplate#1107 migrated it, but the hub's task declares no ref input and checks out the
+  # caller's default ref, where ref: github.sha below is what makes the publish gate validate the exact commit
+  # being published, per D4.6. Adopting it as-is would validate a different tree.
   validate:
     name: Validate job
     needs: [plan]

.github/workflows/test-pull-request.yml

@@ -25,8 +25,8 @@ jobs:
 
   # `!github.event.deleted` skips a branch-deletion push (github.sha is all-zeros, so checkout/build fail).
   # The same unit-test + lint gate the publisher runs, so the PR gate and the publish gate are identical.
-  # Still this repo's own validate-task.yml rather than the hub's: the hub's unit-test step is the VSTest
-  # invocation that Microsoft.Testing.Platform rejects on the .NET 10 SDK (ptr727/ProjectTemplate#1088).
+  # Still this repo's own validate-task.yml rather than the hub's. The unit-test step matches the hub's now,
+  # but the hub's task declares no ref input, which publish-release.yml's own validate job needs (see there).
   validate:
     name: Validate job
     if: ${{ !github.event.deleted }}

.github/workflows/validate-task.yml

@@ -32,10 +32,20 @@ jobs:
 
       # Builds with TreatWarningsAsErrors, so analyzer and code-style warnings fail here.
       # global.json opts dotnet test into Microsoft.Testing.Platform (MTP), the .NET 10 SDK's replacement for
-      # the VSTest runner; --coverlet drives coverlet.MTP (coverlet.collector's VSTest data collector is silently
-      # ignored under MTP) to emit Cobertura XML into ./coverage/.
+      # the VSTest runner, and Microsoft.Testing.Extensions.CodeCoverage emits the Cobertura XML.
+      # --coverage-output stays unset, since pinning one filename gives every test project in the solution the
+      # same path and the last to finish overwrites the rest. The default <guid>.cobertura.xml it writes instead
+      # is a name codecov-cli's own file finder does not match, its patterns being *coverage*.* and an exact
+      # cobertura.xml, so each report is prefixed rather than renamed, keeping the guid that makes it unique.
+      # This step is byte-identical to the hub validator's own, so the two gates cannot drift on coverage.
       - name: Run unit tests step
-        run: dotnet test --coverlet --coverlet-output-format cobertura --results-directory ./coverage
+        run: |
+          set -Eeuo pipefail
+          dotnet test --coverage --coverage-output-format cobertura --results-directory ./coverage
+          for report in ./coverage/*.cobertura.xml; do
+            [ -e "$report" ] || continue
+            mv "$report" "./coverage/coverage-$(basename "$report")"
+          done
 
       # Report-only: fail_ci_if_error is false so a Codecov hiccup or an absent token never fails the gate.
       - name: Upload coverage to Codecov step

.gitignore

@@ -8,6 +8,9 @@
 .artifacts
 .codex
 coverage/
+# MTP writes <guid>.cobertura.xml, into ./TestResults when a run names no --results-directory.
+*.cobertura.xml
+TestResults/
 .DS_Store
 
 *.log

ARCHITECTURE.md

@@ -381,7 +381,7 @@ Two entry-point workflows, whose build and publish jobs are thin callers of the
 
 - **test-pull-request.yml**: CI on every push. `validate` (this repo's own `validate-task.yml`, unit tests plus the full lint set) and `smoke-build` (the hub's `build-release-task.yml` with `smoke: true`, which builds both targets and hard-disables every publish path) feed the `Check pull request workflow status` aggregator, whose name is the ruleset-bound required check.
 - **publish-release.yml**: the sole publisher (weekly `schedule` plus `workflow_dispatch`). `plan` (the hub's `publish-plan-task.yml`) makes the release-gate decision once, `validate` re-runs the gate on the branch tip, `publish` (the hub's `build-release-task.yml`) versions once and builds the executable 7z and the multi-arch Docker image before cutting the GitHub release, and `publish-docker-readme` (the hub's `publish-docker-readme-task.yml`) pushes the Docker Hub overview on `main`.
-- **validate-task.yml** is the one task still carried here rather than reached at the hub, because the hub's own unit-test step is the VSTest invocation that Microsoft.Testing.Platform rejects on the .NET 10 SDK (ptr727/ProjectTemplate#1088). It converges once that lands.
+- **validate-task.yml** is the one task still carried here rather than reached at the hub. Its unit-test step now matches the hub's, which ptr727/ProjectTemplate#1107 migrated to Microsoft.Testing.Platform, so that is no longer the blocker. The hub's task declares no `ref` input and checks out the caller's default ref, while the `validate` job in `publish-release.yml` passes `github.sha` so the publish gate validates the exact commit being published (D4.6), so adopting it as-is would validate a different tree.
 - The executable and Docker builds run the hub's default hooks rather than repo-specific ones: `dotnet_publish_project` names `./PlexCleaner/PlexCleaner.csproj`, which the default publishes across the 7-runtime matrix and archives as `PlexCleaner.7z`, and `docker_image` names `ptr727/plexcleaner`, which the default builds from `./Docker/Dockerfile` for `linux/amd64,linux/arm64` on a `main` publish.
 - Version info: `version.json` with Nerdbank.GitVersioning format. The hub's `get-version-task.yml`, reached from inside `build-release-task.yml`, surfaces `SemVer2`, the assembly versions, and `GitCommitId` (used to pin the release `target_commitish`).
 - Branches: `main` (stable releases, `latest`), `develop` (pre-releases, `develop`).

Directory.Packages.props

@@ -2,11 +2,22 @@
   <ItemGroup>
     <PackageVersion Include="AwesomeAssertions" Version="9.6.0" />
     <PackageVersion Include="CliWrap" Version="3.10.5" />
-    <!-- coverlet.MTP replaces coverlet.collector: the VSTest data collector is silently ignored
-         under Microsoft.Testing.Platform (MTP0001), so coverage needs the MTP-native extension. -->
-    <PackageVersion Include="coverlet.MTP" Version="10.0.1" />
     <PackageVersion Include="Microsoft.NET.Test.Sdk" Version="18.9.0" />
     <PackageVersion Include="Microsoft.SourceLink.GitHub" Version="10.0.400" />
+    <!-- The MTP-native coverage extension WORKFLOW.md D1.2 requires of an MTP-based test project.
+         It replaces coverlet.MTP here, the interim choice made before ptr727/ProjectTemplate#1088
+         resolved the fleet on this package. The baseline it displaces further back is the VSTest
+         coverlet.collector, whose data collector MTP ignores without failing, which is the wording
+         D1.2 itself uses.
+         The 18.9.0 floor is load-bearing rather than cautionary, and it takes two reasons rather
+         than one. Below 18.1.0 the extension is built against Microsoft.Testing.Platform 1.x, so an
+         18.0.x resolution throws a TypeLoadException against the 2.x platform xunit.v3 4.0.0
+         carries, runs zero tests, and still writes a well-formed Cobertura file reporting full
+         coverage, leaving only the non-zero exit to say the run reported nothing. 18.9.0 is then
+         the first release on Microsoft.Testing.Platform 2.3.x, where every test project writes into
+         the one shared results directory the invocation names rather than resolving that relative
+         path per project. Do not lower the floor to 18.1.0 on the first reason alone. -->
+    <PackageVersion Include="Microsoft.Testing.Extensions.CodeCoverage" Version="18.10.0" />
     <PackageVersion Include="NEbml" Version="1.1.0.5" />
     <PackageVersion Include="ptr727.LanguageTags" Version="1.5.90" />
     <PackageVersion Include="ptr727.Utilities" Version="4.0.38" />

PlexCleanerTests/PlexCleanerTests.csproj

@@ -10,14 +10,16 @@
       <PrivateAssets>all</PrivateAssets>
       <IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>
     </PackageReference>
-    <!-- coverlet.MTP is a native Microsoft.Testing.Platform extension, not a build-time-only tool
-         like the VSTest coverlet.collector was: its self-registration codegen needs the package on
-         this project's own compile-time closure, so IncludeAssets must not exclude "compile" (the
-         collector's restricted list omitted it, which is fine for a VSTest data collector but
-         breaks a compiled-against library). PrivateAssets is unrelated to that and stays unset,
-         since it only controls exposure to downstream consumers, which this test project has none
-         of. xunit.runner.visualstudio is gone with the VSTest runner it adapted. -->
-    <PackageReference Include="coverlet.MTP" />
+    <!-- Microsoft.Testing.Extensions.CodeCoverage replaces coverlet.MTP, per WORKFLOW.md D1.2.
+         Like it, and unlike the VSTest coverlet.collector both displace, it is a native
+         Microsoft.Testing.Platform extension rather than a build-time-only tool: its
+         self-registration codegen needs the package on this project's own compile-time closure, so
+         IncludeAssets must not exclude "compile" (the collector's restricted list omitted it, which
+         is fine for a VSTest data collector but breaks a compiled-against library). A build failure
+         is what enforces that, since the generated SelfRegisteredExtensions.cs calls into the
+         package directly. PrivateAssets is unrelated and stays unset, since it only controls
+         exposure to downstream consumers, which this test project has none of. -->
+    <PackageReference Include="Microsoft.Testing.Extensions.CodeCoverage" />
   </ItemGroup>
   <ItemGroup>
     <ProjectReference Include="..\PlexCleaner\PlexCleaner.csproj" />

WORKFLOW.md

@@ -30,9 +30,12 @@ Dependabot pull requests merge themselves once their checks pass.
 The **build, publish, plan, merge-bot and Docker-Hub-overview jobs are thin callers of hub-hosted reusable
 tasks** in `ptr727/ProjectTemplate`, reached by a commit-SHA `uses:` pin that Dependabot bumps, per that
 repo's `docs/reusable-workflows.md`. This repo carries no copy of them. The one task still carried here is
-`validate-task.yml`, because the hub's own unit-test step is the VSTest invocation that
-Microsoft.Testing.Platform rejects on the .NET 10 SDK (ptr727/ProjectTemplate#1088); it converges once that
-lands.
+`validate-task.yml`. Its unit-test step is now byte-identical to the hub's, which
+ptr727/ProjectTemplate#1107 migrated to Microsoft.Testing.Platform, so that is no longer what blocks
+adoption. What blocks it is that the hub's task declares no `ref` input and checks out the caller's default
+ref, where the `validate` job in `publish-release.yml` passes `github.sha` so the publish gate validates the
+exact commit being published, which is D4.6. Adopting the hub task without a `ref` input there would
+silently validate a different tree.
 
 ### Glossary
 
@@ -333,8 +336,20 @@ Each is a **MUST**, stated as input -> output plus the failure it prevents.
 - **D1.2 Unit tests always run.** Output: `validate-task`'s `unit-test` job runs `dotnet test` (build with
   `TreatWarningsAsErrors`, so analyzer/style warnings fail here). [`global.json`](./global.json) opts the run
   into Microsoft.Testing.Platform, which the .NET 10 SDK requires of a test project carrying
-  `Microsoft.Testing.Platform.MSBuild`, and `--coverlet --coverlet-output-format cobertura` drives
-  `coverlet.MTP` to emit the Cobertura XML the Codecov upload reads.
+  `Microsoft.Testing.Platform.MSBuild`, and `--coverage --coverage-output-format cobertura` drives
+  `Microsoft.Testing.Extensions.CodeCoverage` to emit the Cobertura XML the Codecov upload reads. Two details
+  of that invocation are load-bearing and neither fails the job on its own, so both are asserted in 5A.
+  `--coverage-output` stays unset, because pinning one filename gives every test project in the solution the
+  same path and the last to finish overwrites the rest. The `<guid>.cobertura.xml` default it writes instead is
+  a name `codecov-cli`'s own file finder does not match (its patterns are `*coverage*.*` and an exact
+  `cobertura.xml`), so the step prefixes each report to `coverage-<guid>.cobertura.xml`, keeping the guid that
+  makes it unique. The extension is pinned at or above **18.9.0**, for two reasons rather than one. Below
+  18.1.0 it is built against Microsoft.Testing.Platform 1.x, so an 18.0.x resolution throws a
+  `TypeLoadException` against the 2.x platform xunit.v3 4.0.0 carries, runs zero tests, and still writes a
+  well-formed Cobertura file reporting full coverage, leaving only the non-zero exit to say the run reported
+  nothing. 18.9.0 is then the first release on Microsoft.Testing.Platform 2.3.x, where every test project
+  writes into the one shared `--results-directory` the invocation names rather than resolving that relative
+  path per project, which is what the rename loop's glob depends on.
 - **D1.3 Lint enforces the editor checks in CI.** Output: `validate-task`'s `lint` job runs CSharpier check,
   `dotnet format style --verify-no-changes`, `markdownlint-cli2`, `cspell` on the user-facing docs (README,
   HISTORY), `ruff` and `mypy` over the `RegressionTests` Python tooling, `actionlint` (which shellchecks every
@@ -507,8 +522,11 @@ Read the workflow files plus `version.json` and assert the fact behind each appl
   exists under `.github/workflows/`.
 - **D1:** CI runs on `push` with no paths filter; `validate` + `smoke-build` (both targets, `smoke: true`)
   run; every build `upload-artifact` is gated `!smoke`; `global.json` declares
-  `test.runner = Microsoft.Testing.Platform` and the unit-test step passes `--coverlet
-  --coverlet-output-format cobertura`; `lint` runs CSharpier, `dotnet format style`, markdownlint, cspell on
+  `test.runner = Microsoft.Testing.Platform`, the unit-test step passes `--coverage
+  --coverage-output-format cobertura` with no `--coverage-output`, and prefixes each report to
+  `coverage-<guid>.cobertura.xml` before the upload reads the directory;
+  `Directory.Packages.props` pins `Microsoft.Testing.Extensions.CodeCoverage` at 18.9.0 or above;
+  `lint` runs CSharpier, `dotnet format style`, markdownlint, cspell on
   README/HISTORY, ruff, mypy, actionlint, editorconfig-checker; the aggregator `needs:` both and blocks on
   non-success.
 - **D2:** the hub task's `validate-release` job runs before the build jobs and they `needs:` it; it checks