Feat: IsNullableValueType

Author: AnnaSasDev

src/CodeOfChaos.Extensions/ReflectionHelpers.cs

@@ -29,4 +29,10 @@ public static bool IsNullableReferenceType(this ParameterInfo parameter) {
         return nullabilityFlag == 2;
 
     }
+    
+    // WHY IS THIS SO EASY!
+    public static bool IsNullableValueType(this ParameterInfo parameter) {
+        return Nullable.GetUnderlyingType(parameter.ParameterType) != null;
+    }
+
 }

tests/Tests.CodeOfChaos.Extensions/ReflectionHelperTests.cs

@@ -16,8 +16,9 @@ private class TestClass
         public static void MethodWithNullability(
             string nonNullable, 
             string? nullable, 
-            int valueType) 
-        { }
+            int valueType,
+            int? nullableValueType
+        ) { }
     }
 
     // -----------------------------------------------------------------------------------------------------------------
@@ -64,5 +65,75 @@ public async Task IsNullableReferenceType_ShouldReturnFalse_ForValueType()
         // Assert
         await Assert.That(result).IsFalse().Because("Expected parameter 'valueType' to be recognized as a non-nullable reference type.");
     }
+    
+    [Test]
+    public async Task IsNullableReferenceType_ShouldReturnFalse_ForNullableValueType()
+    {
+        // Arrange
+        MethodInfo method = typeof(TestClass).GetMethod(nameof(TestClass.MethodWithNullability))!;
+        ParameterInfo nullableValueTypeParameter = method.GetParameters().First(p => p.Name == "nullableValueType");
+
+        // Act
+        bool result = nullableValueTypeParameter.IsNullableReferenceType();
+
+        // Assert
+        await Assert.That(result).IsFalse().Because("Expected parameter 'nullableInt' to be recognized as not a nullable reference type (it's a nullable value type).");
+    }
+
+    [Test]
+    public async Task IsNullableValueType_ShouldReturnFalse_ForReferenceType()
+    {
+        // Arrange
+        MethodInfo method = typeof(TestClass).GetMethod(nameof(TestClass.MethodWithNullability))!;
+        ParameterInfo referenceTypeParameter = method.GetParameters().First(p => p.Name == "nonNullable");
+
+        // Act
+        bool result = referenceTypeParameter.IsNullableValueType();
+
+        // Assert
+        await Assert.That(result).IsFalse().Because("Expected parameter 'nonNullable' to not be a nullable value type (it's a reference type).");
+    }
+
+    [Test]
+    public async Task IsNullableValueType_ShouldReturnFalse_ForNonNullableValueType()
+    {
+        // Arrange
+        MethodInfo method = typeof(TestClass).GetMethod(nameof(TestClass.MethodWithNullability))!;
+        ParameterInfo valueTypeParameter = method.GetParameters().First(p => p.Name == "valueType");
+
+        // Act
+        bool result = valueTypeParameter.IsNullableValueType();
+
+        // Assert
+        await Assert.That(result).IsFalse().Because("Expected parameter 'valueType' to not be a nullable value type (it's a non-nullable value type).");
+    }
+
+    [Test]
+    public async Task IsNullableValueType_ShouldReturnTrue_ForNullableValueType()
+    {
+        // Arrange
+        MethodInfo method = typeof(TestClass).GetMethod(nameof(TestClass.MethodWithNullability))!;
+        ParameterInfo nullableValueTypeParameter = method.GetParameters().First(p => p.Name == "nullableValueType");
+
+        // Act
+        bool result = nullableValueTypeParameter.IsNullableValueType();
+
+        // Assert
+        await Assert.That(result).IsTrue().Because("Expected parameter 'nullableValueType' to be recognized as a nullable value type.");
+    }
+
+    [Test]
+    public async Task IsNullableValueType_ShouldReturnFalse_ForNullableReferenceType()
+    {
+        // Arrange
+        MethodInfo method = typeof(TestClass).GetMethod(nameof(TestClass.MethodWithNullability))!;
+        ParameterInfo nullableParameter = method.GetParameters().First(p => p.Name == "nullable");
+
+        // Act
+        bool result = nullableParameter.IsNullableValueType();
+
+        // Assert
+        await Assert.That(result).IsFalse().Because("Expected parameter 'nullable' to not be a nullable value type (it's a nullable reference type).");
+    }
 
 }