Make a skipped test impossible to write

`MEOS.NET.Tests/BannedSymbols.txt` names every construct MSTest offers for
stopping a test from asserting — the `[Ignore]` attribute and the three
`Assert.Inconclusive` overloads — and `RS0030` is an error in the test project,
so each one fails the build rather than reaching a reviewer, a log or a count. A
skipped test asserts nothing and reads as a pass in the conclusion, which is why
the construct is refused at the compiler rather than tallied afterwards.

Deleting a test is then the only remaining way to stop running it, and that
leaves no skip behind. What moves is the total, so the workflow reads the run
through `MobilityDB/MEOS-API/.github/actions/check-test-outcome` against a floor
of 67: the same rules every other binding in the ecosystem is held to, from the
one runnable definition, so the CI answer and the answer a developer gets by
hand cannot differ. The run the floor is taken from collects the whole suite —
the snapshot step above it narrows with `--filter` deliberately and no count is
read from that one.

Four refuters, each measured. `[Ignore("refuter")]` on a test takes
`error RS0030: The symbol 'IgnoreAttribute' is banned in this project`, and
`Assert.Inconclusive("refuter")` in a body takes the same error naming
`Assert.Inconclusive(string?)`; both read `Build FAILED`. Against the suite's own
log the guard reads `total=67 skipped=0 floor=67` and passes, while a floor of 68
is refused as a shrinking suite and a log whose summary carries `Skipped: 1` is
refused as a skip. Without all four the pair would be configuration rather than
enforcement.

The suite passes 67 of 67 with none skipped, and the build takes 0 warnings.

Author: estebanzimanyi

.github/workflows/ci.yml

@@ -53,11 +53,25 @@ jobs:
       - name: Build solution
         run: dotnet build MEOS.NET.sln -c Release
 
+      # No --filter here: this run is the one the floor below is read from, so it
+      # collects the whole suite. The snapshot step above narrows deliberately and
+      # its result is not what any count is taken from.
       - name: Run tests
-        run: dotnet test MEOS.NET.sln -c Release --no-build
+        run: dotnet test MEOS.NET.sln -c Release --no-build 2>&1 | tee test.log
         env:
           LD_LIBRARY_PATH: ${{ steps.provision.outputs.libmeos-prefix }}/lib
 
+      # A skip is already impossible to WRITE — MEOS.NET.Tests/BannedSymbols.txt
+      # makes [Ignore] and Assert.Inconclusive compile errors. Deleting a test is
+      # the remaining way to stop running it, and that leaves no skip behind, so
+      # the total carries a floor. Raise it when the suite grows; lowering it is a
+      # deliberate act belonging to the commit that removes the tests.
+      - name: Refuse a skipped test and a shrinking suite
+        uses: MobilityDB/MEOS-API/.github/actions/check-test-outcome@master
+        with:
+          log: test.log
+          min-tests: "67"
+
       - name: Smoke-test the FFI
         run: dotnet run --project ExampleApp/ExampleApp.csproj -c Release --no-build
         env:

MEOS.NET.Tests/BannedSymbols.txt

@@ -0,0 +1,14 @@
+; Every way MSTest lets a test stop asserting while the run still reports success.
+; BannedApiAnalyzers resolves each entry to a symbol and RS0030 is an ERROR here, so a
+; skip does not reach a reviewer, a CI log or a floor — it fails to compile.
+;
+; A skipped test asserts nothing and reads as a pass in the conclusion, which is the
+; whole reason the construct is banned rather than merely counted. Deleting a test is
+; then the only remaining way to stop running it, and that moves the total, which the
+; floor in the workflow refuses.
+;
+; Format: <documentation-comment ID>;<message shown at the error>.
+T:Microsoft.VisualStudio.TestTools.UnitTesting.IgnoreAttribute;A test that does not run asserts nothing. Fix or delete the test — the suite carries no skips.
+M:Microsoft.VisualStudio.TestTools.UnitTesting.Assert.Inconclusive;Inconclusive reports as skipped and reads as a pass. Assert the real outcome, or delete the test.
+M:Microsoft.VisualStudio.TestTools.UnitTesting.Assert.Inconclusive(System.String);Inconclusive reports as skipped and reads as a pass. Assert the real outcome, or delete the test.
+M:Microsoft.VisualStudio.TestTools.UnitTesting.Assert.Inconclusive(System.String,System.Object[]);Inconclusive reports as skipped and reads as a pass. Assert the real outcome, or delete the test.

MEOS.NET.Tests/MEOS.NET.Tests.csproj

@@ -7,13 +7,28 @@
 
     <IsPackable>false</IsPackable>
     <IsTestProject>true</IsTestProject>
+
+    <!-- A banned symbol is an ERROR, not a warning: a warning is a thing a build
+         prints and a reader scrolls past, so it leaves the skip reachable. RS0030
+         is the diagnostic BannedApiAnalyzers raises for every entry in
+         BannedSymbols.txt. -->
+    <WarningsAsErrors>$(WarningsAsErrors);RS0030</WarningsAsErrors>
   </PropertyGroup>
 
   <ItemGroup>
     <PackageReference Include="Microsoft.NET.Test.Sdk" Version="17.9.0" />
     <PackageReference Include="MSTest.TestAdapter" Version="3.3.1" />
     <PackageReference Include="MSTest.TestFramework" Version="3.3.1" />
     <PackageReference Include="coverlet.collector" Version="6.0.2" />
+    <!-- Resolves BannedSymbols.txt and refuses every construct it names. -->
+    <PackageReference Include="Microsoft.CodeAnalysis.BannedApiAnalyzers" Version="3.3.4">
+      <PrivateAssets>all</PrivateAssets>
+      <IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>
+    </PackageReference>
+  </ItemGroup>
+
+  <ItemGroup>
+    <AdditionalFiles Include="BannedSymbols.txt" />
   </ItemGroup>
 
   <ItemGroup>