Adding generator for generating extension method when IOptions is referenced

Author: Keboo

Directory.Build.props

@@ -1,7 +1,7 @@
 <Project>
 
   <PropertyGroup>
-    <LangVersion>10.0</LangVersion>
+    <LangVersion>11.0</LangVersion>
     <Nullable>enable</Nullable>
     <ImplicitUsings>enable</ImplicitUsings>
     <EnforceCodeStyleInBuild Condition=" '$(BuildingForLiveUnitTesting)' == '' ">true</EnforceCodeStyleInBuild>

Directory.Packages.props

@@ -7,6 +7,7 @@
     <PackageVersion Include="Microsoft.CodeAnalysis" Version="4.3.0" />
     <PackageVersion Include="Microsoft.CodeAnalysis.CSharp" Version="4.3.0" />
     <PackageVersion Include="Microsoft.CodeAnalysis.CSharp.SourceGenerators.Testing.MSTest" Version="1.1.1" />
+    <PackageVersion Include="Microsoft.Extensions.Options" Version="8.0.1" />
     <PackageVersion Include="Microsoft.NET.Test.Sdk" Version="17.8.0" />
     <PackageVersion Include="Microsoft.SourceLink.GitHub" Version="8.0.0" />
     <PackageVersion Include="Moq" Version="4.20.70" />

GeneratorTests/Moq.AutoMock.Generator.Example.MSTest/ControllerWithOptionsTests.cs

@@ -0,0 +1,19 @@
+using Microsoft.Extensions.Options;
+using Microsoft.VisualStudio.TestTools.UnitTesting;
+
+namespace Moq.AutoMock.Generator.Example.MSUnit;
+[TestClass]
+public class ControllerWithOptionsTests
+{
+    [TestMethod]
+    public void CreateInstance_WithOptions_EmbedsOptions()
+    {
+        AutoMocker mocker = new();
+        
+        mocker.WithOptions<TestsOptions>(options => options.Number = 42);
+
+        ControllerWithOptions controller = mocker.CreateInstance<ControllerWithOptions>();
+
+        Assert.AreEqual(42, controller.Options.Value.Number);
+    }
+}

GeneratorTests/Moq.AutoMock.Generator.Example.NUnit/ControllerWithOptionsTests.cs

@@ -0,0 +1,18 @@
+using Microsoft.Extensions.Options;
+using NUnit.Framework;
+
+namespace Moq.AutoMock.Generator.Example.NUnit;
+public class ControllerWithOptionsTests
+{
+    [Test]
+    public void CreateInstance_WithOptions_EmbedsOptions()
+    {
+        AutoMocker mocker = new();
+        
+        mocker.WithOptions<TestsOptions>(options => options.Number = 42);
+
+        ControllerWithOptions controller = mocker.CreateInstance<ControllerWithOptions>();
+
+        Assert.That(42 == controller.Options.Value.Number);
+    }
+}

GeneratorTests/Moq.AutoMock.Generator.Example.xUnit/ControllerWithOptionsTests.cs

@@ -0,0 +1,18 @@
+using Microsoft.Extensions.Options;
+using Xunit;
+
+namespace Moq.AutoMock.Generator.Example.xUnit;
+public class ControllerWithOptionsTests
+{
+    [Fact]
+    public void CreateInstance_WithOptions_EmbedsOptions()
+    {
+        AutoMocker mocker = new();
+        
+        mocker.WithOptions<TestsOptions>(options => options.Number = 42);
+
+        ControllerWithOptions controller = mocker.CreateInstance<ControllerWithOptions>();
+
+        Assert.Equal(42, controller.Options.Value.Number);
+    }
+}

GeneratorTests/Moq.AutoMocker.Generator.Example/ControllerWithOptions.cs

@@ -0,0 +1,12 @@
+using Microsoft.Extensions.Options;
+
+namespace Moq.AutoMock.Generator.Example;
+public class ControllerWithOptions
+{
+    public IOptions<TestsOptions> Options { get; }
+
+    public ControllerWithOptions(IOptions<TestsOptions> options)
+    {
+        Options = options;
+    }
+}

GeneratorTests/Moq.AutoMocker.Generator.Example/Moq.AutoMock.Generator.Example.csproj

@@ -1,4 +1,4 @@
-<Project Sdk="Microsoft.NET.Sdk">
+<Project Sdk="Microsoft.NET.Sdk">
 
   <PropertyGroup>
     <TargetFramework>net6.0</TargetFramework>
@@ -7,4 +7,8 @@
     <IsPackable>false</IsPackable>
   </PropertyGroup>
 
+  <ItemGroup>
+    <PackageReference Include="Microsoft.Extensions.Options" />
+  </ItemGroup>
+
 </Project>

GeneratorTests/Moq.AutoMocker.Generator.Example/TestsOptions.cs

@@ -0,0 +1,6 @@
+namespace Moq.AutoMock.Generator.Example;
+
+public class TestsOptions
+{
+    public int Number { get; set; }
+}

Moq.AutoMocker.Generators/OptionsExtensionSourceGenerator.cs

@@ -0,0 +1,66 @@
+using Microsoft.CodeAnalysis;
+
+namespace Moq.AutoMocker.Generators;
+
+[Generator]
+public class OptionsExtensionSourceGenerator : ISourceGenerator
+{
+    public void Execute(GeneratorExecutionContext context)
+    {
+        if (!ReferencesOptions(context.Compilation.ReferencedAssemblyNames))
+        {
+            return;
+        }
+
+        context.AddSource("AutoMocker.Options.cs", OptionsExtensionContent);
+    }
+
+    public void Initialize(GeneratorInitializationContext context)
+    { }
+
+    private static bool ReferencesOptions(IEnumerable<AssemblyIdentity> assemblies)
+    {
+        foreach (AssemblyIdentity assembly in assemblies)
+        {
+            if (assembly.Name.StartsWith("Microsoft.Extensions.Options"))
+            {
+                return true;
+            }
+        }
+        return false;
+    }
+
+    private const string OptionsExtensionContent =
+        """
+        namespace Moq.AutoMock
+        {
+            using Microsoft.Extensions.Options;
+
+            public static class AutoMockerOptionsExtensions
+            {
+                /// <summary>
+                ///  This method sets up <see cref="AutoMocker"/> with various option related services for Microsoft's Option pattern, and allows their interception and manipulation in testing scenarios.
+                /// </summary>
+                /// <param name="mocker">The <see cref="AutoMocker"/> instance</param>
+                /// <param name="configure">A delegate that can be used to configure an option instance of type TClass.</param>
+                /// <typeparam name="TClass">The type of Options being configured.</typeparam>
+                /// <returns>The same <see cref="AutoMocker"/> instance passed as parameter, allowing chained calls.</returns>
+                public static AutoMocker WithOptions<TClass>(this AutoMocker mocker, Action<TClass>? configure = null)
+                    where TClass : class, new()
+                {
+                    if (mocker == null) throw new ArgumentNullException(nameof(mocker));
+
+                    mocker.Use<IEnumerable<IConfigureOptions<TClass>>>(new[] { new ConfigureOptions<TClass>(configure) });
+                    mocker.With<IOptionsMonitorCache<TClass>, OptionsCache<TClass>>();
+                    mocker.With<IOptionsFactory<TClass>, OptionsFactory<TClass>>();
+                    mocker.With<IOptionsMonitor<TClass>, OptionsMonitor<TClass>>();
+                    mocker.With<IOptionsSnapshot<TClass>, OptionsManager<TClass>>();
+                    TClass options = mocker.Get<IOptionsFactory<TClass>>().Create(string.Empty);
+                    mocker.Use(Options.Create(options));
+                    mocker.Use(options);
+                    return mocker;
+                }
+            }
+        }
+        """;
+}