revert: Restore .NET Standard 2.0 (#1312)

We'd prematurely removed .NET Standard 2.0
We do plan on removing it for version 3 since it will limit use of newer SDK features with better overall performance.

.github/workflows/test-indicators.yml

@@ -1,11 +1,11 @@
-name: Indicators
+name: Test Indicators
 
 on:
   push:
     branches: ["main"]
-
   pull_request:
     branches: ["*"]
+  workflow_dispatch:
 
 jobs:
   test:
@@ -20,38 +20,29 @@ jobs:
     strategy:
       matrix:
         os: [windows-latest, ubuntu-latest, macos-latest]
-        dotnet-version: ["9.x"]
-        # TODO: restore when runners have 9.x on all
-        # ["2.1.x", "6.x", "9.x"]
+        dotnet-version: ["6.0.x", "9.0.x"]
 
     env:
 
       # identifying primary configuration so only one reports coverage
-      IS_PRIMARY: ${{ matrix.os == 'ubuntu-latest' && matrix.dotnet-version == '9.x' }}
+      IS_PRIMARY: ${{ matrix.os == 'ubuntu-latest' && matrix.dotnet-version == '9.0.x' }}
 
-      # .NET SDK versions in the matrix that support `ga` quality spec
-      #   versions before 5.x do not support it
-      SUPPORT_GA: ${{ contains(fromJson('["6.x", "9.x"]'), matrix.dotnet-version) }}
+      # Identifies the current target framework
+      TARGET_FRAMEWORK: >
+        ${{ matrix.dotnet-version == '6.0.x' && 'net6.0' ||
+            matrix.dotnet-version == '9.0.x' && 'net9.0' }}
 
     steps:
 
       - name: Checkout source
         uses: actions/checkout@v4
 
       - name: Setup .NET
-        id: dotnet-new
         uses: actions/setup-dotnet@v4
-        if: env.SUPPORT_GA == 'true'
         with:
-          dotnet-version: ${{ matrix.dotnet-version }}
+          dotnet-version: "9.x"
           dotnet-quality: "ga"
 
-      - name: Setup .NET (older)
-        uses: actions/setup-dotnet@v4
-        if: env.SUPPORT_GA == 'false'
-        with:
-          dotnet-version: ${{ matrix.dotnet-version }}
-
       - name: Build library
         run: >
           dotnet build
@@ -66,6 +57,7 @@ jobs:
         run: >
           dotnet test tests/indicators/Tests.Indicators.csproj
           --configuration Release
+          --property:TestFramework="${{ env.TARGET_FRAMEWORK }}"
           --no-build
           --verbosity normal
           --logger trx
@@ -84,8 +76,8 @@ jobs:
           --logger trx
           --results-directory ./test-other
 
-      - name: Post test summary
-        uses: dorny/test-reporter@v1
+      - name: Post test results
+        uses: dorny/test-reporter@v1.9.1
         if: env.IS_PRIMARY == 'true' && always()
         with:
           name: Test results

.gitignore

@@ -133,6 +133,9 @@ _TeamCity*
 *.coverage
 *.coveragexml
 
+# Visual Studio live unit testing
+*.lutconfig
+
 # NCrunch
 _NCrunch_*
 .*crunch*.local.xml
@@ -218,7 +221,7 @@ ClientBin/
 *.publishsettings
 orleans.codegen.cs
 
-# Including strong name files can present a security risk 
+# Including strong name files can present a security risk
 # (https://github.com/github/gitignore/pull/2483#issue-259490424)
 #*.snk
 
@@ -314,7 +317,7 @@ __pycache__/
 # OpenCover UI analysis results
 OpenCover/
 
-# Azure Stream Analytics local run output 
+# Azure Stream Analytics local run output
 ASALocalRun/
 
 # MSBuild Binary and Structured Log
@@ -323,11 +326,11 @@ ASALocalRun/
 # NVidia Nsight GPU debugger configuration file
 *.nvuser
 
-# MFractors (Xamarin productivity tool) working folder 
+# MFractors (Xamarin productivity tool) working folder
 .mfractor/
 
 # Jekyll site
 _site/
 
 # zip artifacts
-.DS_Store
+.DS_Store

docs/pages/home.md

@@ -70,7 +70,7 @@ See the [guide]({{site.baseurl}}/guide/#content) and the [full list of indicator
 Our [NuGet library](https://www.nuget.org/packages/Skender.Stock.Indicators) directly targets all current frameworks for peak performance, including the .NET Standard for older framework compatibility.
 
 - .NET 9.0, 8.0, 6.0
-- .NET Standard 2.1
+- .NET Standard 2.1, 2.0
 
 The compiled library package is [Common Language Specification (CLS) compliant](https://docs.microsoft.com/en-us/dotnet/standard/common-type-system) and can be used in other programming languages, including Python and everything in the .NET universe.
 

src/Indicators.csproj

@@ -1,7 +1,7 @@
 <Project Sdk="Microsoft.NET.Sdk">
 
   <PropertyGroup>
-    <TargetFrameworks>net9.0;net8.0;net6.0;netstandard2.1</TargetFrameworks>
+    <TargetFrameworks>net9.0;net8.0;net6.0;netstandard2.1;netstandard2.0</TargetFrameworks>
 
     <Authors>Dave Skender</Authors>
     <Product>Stock Indicators for .NET</Product>

tests/indicators/_Initialize.cs

@@ -1,5 +1,7 @@
 using System.Globalization;
+using System.Reflection;
 using System.Runtime.CompilerServices;
+using System.Runtime.Versioning;
 
 // GLOBALS & INITIALIZATION OF TEST DATA
 
@@ -8,6 +10,9 @@
 [assembly: InternalsVisibleTo("Tests.Performance")]
 namespace Tests.Common;
 
+/// <summary>
+/// Base class for all test classes, providing common test data and utilities.
+/// </summary>
 [TestClass]
 public abstract class TestBase
 {
@@ -27,3 +32,37 @@ public abstract class TestBase
     internal static readonly IEnumerable<Quote> zeroesQuotes = TestData.GetZeros();
     internal static readonly IEnumerable<(DateTime, double)> tupleNanny = TestData.GetTupleNaN();
 }
+
+/// <summary>
+/// Test class for the startup of the test project.
+/// </summary>
+[TestClass]
+public class Startup
+{
+    /// <summary>
+    /// Displays the assembly location, name, version, and target framework
+    /// as a sanity check for test runner targeting.
+    /// </summary>
+    [TestMethod]
+    [TestCategory("ShowMe")]
+    public void ShowFramework()
+    {
+        // Get the assembly of any type from your Indicators project
+        Assembly assembly = typeof(Indicator).Assembly;
+
+        Console.WriteLine($"Assembly Location: {assembly.Location}");
+        Console.WriteLine($"Assembly Name: {assembly.GetName().Name}");
+        Console.WriteLine($"Assembly Version: {assembly.GetName().Version}");
+
+        // Get the target framework the assembly was built for
+        TargetFrameworkAttribute targetFrameworkAttribute = assembly
+            .GetCustomAttribute<TargetFrameworkAttribute>();
+
+        string frameworkName
+            = targetFrameworkAttribute?.FrameworkName ?? "Unknown";
+
+        Console.WriteLine($"Target Framework: {frameworkName}");
+
+        frameworkName.Should().NotBe("Unknown");
+    }
+}