test: categorize the tests per tested component

.github/copilot-instructions.md

@@ -22,6 +22,7 @@
 │   ├── AsyncObservable.fs          – Async flavour (cold `Async` terminals, `mapAsync`, `ofAsync`)
 │   └── TaskObservable.fs           – Task flavour (hot `Task` terminals, `mapAsync`, `ofTask`)
 ├── tests/FSharp.Control.R3.Tests/  – MSTest test project
+│   ├── TestCategories.fs           – test category attributes for `--filter TestCategory=...`
 │   ├── BuilderTests.fs             – builder behavior tests
 │   └── ObservableTests.fs          – observable behavior tests
 ├── build/                          – FAKE build scripts and release automation

tests/FSharp.Control.R3.Tests/BuilderTests.fs

@@ -7,7 +7,7 @@ open FSharp.Control.R3.Observable.Builders
 open Microsoft.VisualStudio.TestTools.UnitTesting
 open Swensen.Unquote
 
-[<TestClass>]
+[<TestClass; BuilderTestCategory>]
 type BuilderTests () =
 
     [<TestMethod>]

tests/FSharp.Control.R3.Tests/FSharp.Control.R3.Tests.fsproj

@@ -12,6 +12,7 @@
   </ItemGroup>
 
   <ItemGroup>
+    <Compile Include="TestCategories.fs" />
     <Compile Include="BuilderTests.fs" />
     <Compile Include="ObservableTests.fs" />
   </ItemGroup>

tests/FSharp.Control.R3.Tests/ObservableTests.fs

@@ -6,7 +6,7 @@ open FSharp.Control.R3.Async
 open Microsoft.VisualStudio.TestTools.UnitTesting
 open Swensen.Unquote
 
-[<TestClass>]
+[<TestClass; ObservableTestCategory>]
 type ObservableTests () =
 
     [<TestMethod>]

tests/FSharp.Control.R3.Tests/TestCategories.fs

@@ -0,0 +1,65 @@
+// Every TestCategoryBaseAttribute descendant used to categorize the tests of this project, one per tested component.
+// MSTest picks up their TestCategories through --filter TestCategory=... exactly like [<TestCategory>]'s,
+// but each attribute is self-sufficient: no separate string constant is needed to know what to pass it.
+namespace FSharp.Control.R3.Tests
+
+open System.Collections.Generic
+open Microsoft.VisualStudio.TestTools.UnitTesting
+
+/// <summary>
+/// Categorizes the tests of <see cref="T:FSharp.Control.R3.ProcessingOptions"/> and
+/// <see cref="T:FSharp.Control.R3.AwaitOperationConfiguration"/>.
+/// </summary>
+type ProcessingOptionsTestCategoryAttribute () =
+    inherit TestCategoryBaseAttribute ()
+    override _.TestCategories = [| "ProcessingOptions" |] :> IList<string>
+
+/// <summary>
+/// Categorizes the tests of the functions of the <see cref="T:FSharp.Control.R3.Observable"/> module,
+/// of <see cref="T:FSharp.Control.R3.ObservableOption"/> and of the <see cref="T:FSharp.Control.R3.ObservableFactories.Observable"/> factories.
+/// </summary>
+type ObservableTestCategoryAttribute () =
+    inherit TestCategoryBaseAttribute ()
+    override _.TestCategories = [| "Observable" |] :> IList<string>
+
+/// <summary>
+/// Categorizes the tests of the chunking functions and of <see cref="T:FSharp.Control.R3.ChunkConfiguration`1"/>.
+/// </summary>
+type ChunkTestCategoryAttribute () =
+    inherit TestCategoryBaseAttribute ()
+    override _.TestCategories = [| "Chunk" |] :> IList<string>
+
+/// <summary>
+/// Categorizes the tests of the <see cref="T:FSharp.Control.R3.Observable.BuildersModule.RxQueryBuilder"/> query builder.
+/// </summary>
+type BuilderTestCategoryAttribute () =
+    inherit TestCategoryBaseAttribute ()
+    override _.TestCategories = [| "Builder" |] :> IList<string>
+
+/// <summary>
+/// Categorizes the tests of the Async flavour, <see cref="T:FSharp.Control.R3.Async"/>.
+/// </summary>
+type AsyncTestCategoryAttribute () =
+    inherit TestCategoryBaseAttribute ()
+    override _.TestCategories = [| "Async" |] :> IList<string>
+
+/// <summary>
+/// Categorizes the tests of the Task flavour, <see cref="T:FSharp.Control.R3.Task"/>.
+/// </summary>
+type TaskTestCategoryAttribute () =
+    inherit TestCategoryBaseAttribute ()
+    override _.TestCategories = [| "Task" |] :> IList<string>
+
+/// <summary>
+/// Categorizes the tests of mapAsync, which run every test against both flavours, so they also belong to the Async and Task categories.
+/// </summary>
+type MapAsyncTestCategoryAttribute () =
+    inherit TestCategoryBaseAttribute ()
+    override _.TestCategories = [| "MapAsync"; "Async"; "Task" |] :> IList<string>
+
+/// <summary>
+/// Categorizes the end-to-end scenarios that combine several areas of the library.
+/// </summary>
+type IntegrationTestCategoryAttribute () =
+    inherit TestCategoryBaseAttribute ()
+    override _.TestCategories = [| "Integration" |] :> IList<string>