fix: Generator with nullable or optional parameters (#273)

* Test generator

* #WIP

* NuGet config

* Proof of working

* Fix build error

* Auto stash before merge of "BMichaelis/TestGenerator" and "BenjaminMichaelis/BMichaelis/TestGenerator"

* More test, working generator

* Removing caching of symbol

* Add tests, adjust docs

* More cleanup

* revert global.json update

* Revert "NuGet config". Will be done in #270

This reverts commit b990391.

---------

Co-authored-by: Kevin Bost <kitokeboo@gmail.com>

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

@@ -0,0 +1,15 @@
+using Microsoft.VisualStudio.TestTools.UnitTesting;
+
+namespace Moq.AutoMock.Generator.Example.MSTest;
+
+[TestClass]
+[ConstructorTests(typeof(ControllerWithSomeNullableParameters), Behavior = TestGenerationBehavior.IgnoreNullableParameters)]
+public partial class ControllerNullableParametersTests
+{
+    partial void ControllerWithSomeNullableParametersConstructor_WithNullstring_ThrowsArgumentNullExceptionSetup(AutoMocker mocker)
+    {
+        mocker.Use<string>("");
+        mocker.Use<int?>(42);
+        mocker.Use<int>(24);
+    }
+}

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

@@ -0,0 +1,12 @@
+namespace Moq.AutoMock.Generator.Example.NUnit;
+
+[ConstructorTests(typeof(ControllerWithSomeNullableParameters), Behavior = TestGenerationBehavior.IgnoreNullableParameters)]
+public partial class ControllerNullableParametersTests
+{
+    partial void AutoMockerTestSetup(Moq.AutoMock.AutoMocker mocker, string testName)
+    {
+        mocker.Use<string>("");
+        mocker.Use<int?>(42);
+        mocker.Use<int>(24);
+    }
+}

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

@@ -0,0 +1,12 @@
+namespace Moq.AutoMock.Generator.Example.xUnit;
+
+[ConstructorTests(typeof(ControllerWithSomeNullableParameters), Behavior = TestGenerationBehavior.IgnoreNullableParameters)]
+public partial class ControllerNullableParametersTests
+{
+    partial void AutoMockerTestSetup(Moq.AutoMock.AutoMocker mocker, string testName)
+    {
+        mocker.Use<string>("");
+        mocker.Use<int?>(42);
+        mocker.Use<int>(24);
+    }
+}

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

@@ -0,0 +1,15 @@
+namespace Moq.AutoMock.Generator.Example;
+
+public class ControllerWithSomeNullableParameters
+{
+    public ControllerWithSomeNullableParameters(
+        string name, // Test generated
+        int years, // No test generated
+        string? nullableName, // No test generated
+        string? testName = null, // No test generated
+        string foo = null!, // No test generated
+        int? age = null) // No test generated
+    {
+        ArgumentNullException.ThrowIfNull(name);
+    }
+}

Moq.AutoMock/ConstructorTestsAttribute.cs

@@ -1,5 +1,4 @@
 namespace Moq.AutoMock;
-
 /// <summary>
 /// An attribute used by Moq.AutoMock.TestGenerator to generate unit tests for null constructor arguments.
 /// </summary>
@@ -11,16 +10,31 @@ public class ConstructorTestsAttribute : Attribute
     /// </summary>
     public Type? TargetType { get; set; }
     /// <summary>
+    /// Controls whether to generate tests for nullable reference types.
+    /// </summary>
+    public TestGenerationBehavior Behavior { get; set; }
+    /// <summary>
     /// Create a new instance of the ConstructorTestsAttribute
     /// </summary>
     public ConstructorTestsAttribute()
     { }
     /// <summary>
     /// Create a new instance of the ConstructorTestsAttribute specifying the targetType
     /// </summary>
-    /// <param name="targetType"></param>
+    /// <param name="targetType">The name for which the generator should generate tests for.</param>
     public ConstructorTestsAttribute(Type targetType)
     {
         TargetType = targetType;
     }
+
+    /// <summary>
+    /// Create a new instance of the ConstructorTestsAttribute specifying the targetType
+    /// </summary>
+    /// <param name="targetType">The name for which the generator should generate tests for.</param>
+    /// <param name="behavior">Sets the behavior for the test generator to operate with.</param>
+    public ConstructorTestsAttribute(Type targetType, TestGenerationBehavior behavior)
+    {
+        TargetType = targetType;
+        Behavior = behavior;
+    }
 }

Moq.AutoMock/TestGenerationBehavior.cs

@@ -0,0 +1,22 @@
+namespace Moq.AutoMock;
+
+/// <summary>
+/// Control the behavior of the test generator, such as whether to skip nullable parameters.
+/// </summary>
+public enum TestGenerationBehavior
+{
+    /// <summary>
+    /// The default behavior, which is to generate tests for all parameters.
+    /// </summary>
+    Default,
+
+    /// <summary>
+    /// Skip generating tests for parameters that meet one of the following criteria:
+    /// <list type="bullet">
+    /// <item><description>Nullable reference types are enabled and the parameter type is a nullable reference type.</description></item>
+    /// <item><description>The parameter is a nullable value type.</description></item>
+    /// <item><description>The parameter has a default value of null.</description></item>
+    /// </list>
+    /// </summary>
+    IgnoreNullableParameters
+}