Nullable support using a refiner

JsonSchema.Generation.Tests/GeneratorTests.cs

@@ -149,5 +149,80 @@ public void UriSchema()
 
 			AssertEqual(expected, actual);
 		}
+
+		[Test]
+		public void NullableBooleanSchema()
+		{
+			var expected = new JsonSchemaBuilder()
+				.Type(SchemaValueType.Boolean)
+				.Build();
+
+			var actual = new JsonSchemaBuilder().FromType<bool?>().Build();
+
+			AssertEqual(expected, actual);
+		}
+
+		[Test]
+		public void NullableDateTimeSchema()
+		{
+			var expected = new JsonSchemaBuilder()
+				.Type(SchemaValueType.String)
+				.Format(Formats.DateTime)
+				.Build();
+
+			var actual = new JsonSchemaBuilder().FromType<DateTime?>().Build();
+
+			AssertEqual(expected, actual);
+		}
+
+		[Test]
+		public void NullableEnumSchema()
+		{
+			var expected = new JsonSchemaBuilder()
+				.Enum(Enum.GetNames(typeof(DayOfWeek)).Select(x => x.AsJsonElement()))
+				.Build();
+
+			var actual = new JsonSchemaBuilder().FromType<DayOfWeek?>().Build();
+
+			AssertEqual(expected, actual);
+		}
+
+		[Test]
+		public void NullableGuidSchema()
+		{
+			var expected = new JsonSchemaBuilder()
+				.Type(SchemaValueType.String)
+				.Format(Formats.Uuid)
+				.Build();
+
+			var actual = new JsonSchemaBuilder().FromType<Guid?>().Build();
+
+			AssertEqual(expected, actual);
+		}
+
+		[Test]
+		public void NullableIntegerSchema()
+		{
+			var expected = new JsonSchemaBuilder()
+				.Type(SchemaValueType.Integer)
+				.Build();
+
+			var actual = new JsonSchemaBuilder().FromType<int?>().Build();
+
+			AssertEqual(expected, actual);
+		}
+
+
+		[Test]
+		public void NullableNumberSchema()
+		{
+			var expected = new JsonSchemaBuilder()
+				.Type(SchemaValueType.Number)
+				.Build();
+
+			var actual = new JsonSchemaBuilder().FromType<double?>().Build();
+
+			AssertEqual(expected, actual);
+		}
 	}
 }

JsonSchema.Generation.Tests/NullabilityTests.cs

@@ -0,0 +1,187 @@
+using NUnit.Framework;
+using System;
+using System.Collections.Generic;
+using System.Linq;
+
+namespace Json.Schema.Generation.Tests
+{
+	public class NullabilityTests
+	{
+		public class ReferenceMember
+		{
+			public string Property { get; set; }
+		}
+
+		public class ReferenceMemberWithNull
+		{
+			[Nullable(true)]
+			public string Property { get; set; }
+		}
+
+		public class ReferenceMemberWithNotNull
+		{
+			[Nullable(false)]
+			public string Property { get; set; }
+		}
+
+		public class NullableValueTypeMember
+		{
+			public int? Property { get; set; }
+		}
+
+		public class NullableValueTypeMemberWithNull
+		{
+			[Nullable(true)]
+			public int? Property { get; set; }
+		}
+
+		public class NullableValueTypeMemberWithNotNull
+		{
+			[Nullable(false)]
+			public int? Property { get; set; }
+		}
+
+		public class ValueTypeMember
+		{
+			public int Property { get; set; }
+		}
+
+		public class ValueTypeMemberWithNull
+		{
+			[Nullable(true)]
+			public int Property { get; set; }
+		}
+
+		public class ValueTypeMemberWithNotNull
+		{
+			[Nullable(false)]
+			public int Property { get; set; }
+		}
+
+		private static readonly Nullability Disabled = Nullability.Disabled;
+		private static readonly Nullability AllowForReferenceTypes = Nullability.AllowForReferenceTypes;
+		private static readonly Nullability AllowForNullableValueTypes = Nullability.AllowForNullableValueTypes;
+		private static readonly Nullability AllowForAllTypes = Nullability.AllowForAllTypes;
+
+		private static readonly SchemaValueType String = SchemaValueType.String;
+		private static readonly SchemaValueType Integer = SchemaValueType.Integer;
+		private static readonly SchemaValueType Null = SchemaValueType.Null;
+
+
+		public static IEnumerable<TestCaseData> MemberCases
+		{
+			get
+			{
+				yield return new TestCaseData(Disabled, typeof(ReferenceMember), String);
+				yield return new TestCaseData(Disabled, typeof(ReferenceMemberWithNull), String | Null);
+				yield return new TestCaseData(Disabled, typeof(ReferenceMemberWithNotNull), String);
+				yield return new TestCaseData(AllowForNullableValueTypes, typeof(ReferenceMember), String);
+				yield return new TestCaseData(AllowForNullableValueTypes, typeof(ReferenceMemberWithNull), String | Null);
+				yield return new TestCaseData(AllowForNullableValueTypes, typeof(ReferenceMemberWithNotNull), String);
+				yield return new TestCaseData(AllowForAllTypes, typeof(ReferenceMember), String | Null);
+				yield return new TestCaseData(AllowForAllTypes, typeof(ReferenceMemberWithNull), String | Null);
+				yield return new TestCaseData(AllowForAllTypes, typeof(ReferenceMemberWithNotNull), String);
+				yield return new TestCaseData(AllowForReferenceTypes, typeof(ReferenceMember), String | Null);
+				yield return new TestCaseData(AllowForReferenceTypes, typeof(ReferenceMemberWithNull), String | Null);
+				yield return new TestCaseData(AllowForReferenceTypes, typeof(ReferenceMemberWithNotNull), String);
+
+				yield return new TestCaseData(Disabled, typeof(NullableValueTypeMember), Integer);
+				yield return new TestCaseData(Disabled, typeof(NullableValueTypeMemberWithNull), Integer | Null);
+				yield return new TestCaseData(Disabled, typeof(NullableValueTypeMemberWithNotNull), Integer);
+				yield return new TestCaseData(AllowForNullableValueTypes, typeof(NullableValueTypeMember), Integer | Null);
+				yield return new TestCaseData(AllowForNullableValueTypes, typeof(NullableValueTypeMemberWithNull), Integer | Null);
+				yield return new TestCaseData(AllowForNullableValueTypes, typeof(NullableValueTypeMemberWithNotNull), Integer);
+				yield return new TestCaseData(AllowForAllTypes, typeof(NullableValueTypeMember), Integer | Null);
+				yield return new TestCaseData(AllowForAllTypes, typeof(NullableValueTypeMemberWithNull), Integer | Null);
+				yield return new TestCaseData(AllowForAllTypes, typeof(NullableValueTypeMemberWithNotNull), Integer);
+				yield return new TestCaseData(AllowForReferenceTypes, typeof(NullableValueTypeMember), Integer);
+				yield return new TestCaseData(AllowForReferenceTypes, typeof(NullableValueTypeMemberWithNull), Integer | Null);
+				yield return new TestCaseData(AllowForReferenceTypes, typeof(NullableValueTypeMemberWithNotNull), Integer);
+
+				yield return new TestCaseData(Disabled, typeof(ValueTypeMember), Integer);
+				yield return new TestCaseData(Disabled, typeof(ValueTypeMemberWithNull), Integer | Null);
+				yield return new TestCaseData(Disabled, typeof(ValueTypeMemberWithNotNull), Integer);
+				yield return new TestCaseData(AllowForNullableValueTypes, typeof(ValueTypeMember), Integer);
+				yield return new TestCaseData(AllowForNullableValueTypes, typeof(ValueTypeMemberWithNull), Integer | Null);
+				yield return new TestCaseData(AllowForNullableValueTypes, typeof(ValueTypeMemberWithNotNull), Integer);
+				yield return new TestCaseData(AllowForAllTypes, typeof(ValueTypeMember), Integer);
+				yield return new TestCaseData(AllowForAllTypes, typeof(ValueTypeMemberWithNull), Integer | Null);
+				yield return new TestCaseData(AllowForAllTypes, typeof(ValueTypeMemberWithNotNull), Integer);
+				yield return new TestCaseData(AllowForReferenceTypes, typeof(ValueTypeMember), Integer);
+				yield return new TestCaseData(AllowForReferenceTypes, typeof(ValueTypeMemberWithNull), Integer | Null);
+				yield return new TestCaseData(AllowForReferenceTypes, typeof(ValueTypeMemberWithNotNull), Integer);
+
+			}
+		}
+
+		[TestCaseSource(nameof(MemberCases))]
+		public void MemberNullability(Nullability nullability, Type type, SchemaValueType valueType)
+		{
+			var config = new SchemaGeneratorConfiguration
+			{
+				Nullability = nullability
+			};
+
+			// Nullability affects root schema so only PropertiesKeywords are compared
+			var expected = new JsonSchemaBuilder()
+				.Properties(
+					(nameof(ReferenceMember.Property), new JsonSchemaBuilder().Type(valueType)))
+				.Build()
+				.Keywords
+				.OfType<PropertiesKeyword>()
+				.First();
+
+			var actual = new JsonSchemaBuilder()
+				.FromType(type, config)
+				.Build()
+				.Keywords
+				.OfType<PropertiesKeyword>()
+				.First();
+
+			Assert.AreEqual(expected, actual);
+		}
+
+
+		public static IEnumerable<TestCaseData> TypeCases
+		{
+			get
+			{
+				yield return new TestCaseData(Disabled, typeof(string), String);
+				yield return new TestCaseData(AllowForNullableValueTypes, typeof(string), String);
+				yield return new TestCaseData(AllowForAllTypes, typeof(string), String | Null);
+				yield return new TestCaseData(AllowForReferenceTypes, typeof(string), String | Null);
+
+				yield return new TestCaseData(Disabled, typeof(int?), Integer);
+				yield return new TestCaseData(AllowForNullableValueTypes, typeof(int?), Integer | Null);
+				yield return new TestCaseData(AllowForAllTypes, typeof(int?), Integer | Null);
+				yield return new TestCaseData(AllowForReferenceTypes, typeof(int?), Integer);
+
+				yield return new TestCaseData(Disabled, typeof(int), Integer);
+				yield return new TestCaseData(AllowForNullableValueTypes, typeof(int), Integer);
+				yield return new TestCaseData(AllowForAllTypes, typeof(int), Integer);
+				yield return new TestCaseData(AllowForReferenceTypes, typeof(int), Integer);
+
+			}
+		}
+
+		[TestCaseSource(nameof(TypeCases))]
+		public void TypeNullability(Nullability nullability, Type type, SchemaValueType valueType)
+		{
+			var config = new SchemaGeneratorConfiguration
+			{
+				Nullability = nullability
+			};
+
+			var expected = new JsonSchemaBuilder()
+				.Type(valueType)
+				.Build();
+
+			var actual = new JsonSchemaBuilder()
+				.FromType(type, config)
+				.Build();
+
+			Assert.AreEqual(expected, actual);
+		}
+
+	}
+}

JsonSchema.Generation.Tests/SchemaGenerationTests.cs

@@ -25,6 +25,17 @@ public static IEnumerable<TestCaseData> SimpleTypeCases
 				yield return new TestCaseData(typeof(float), SchemaValueType.Number);
 				yield return new TestCaseData(typeof(double), SchemaValueType.Number);
 				yield return new TestCaseData(typeof(decimal), SchemaValueType.Number);
+				yield return new TestCaseData(typeof(bool?), SchemaValueType.Boolean);
+				yield return new TestCaseData(typeof(byte?), SchemaValueType.Integer);
+				yield return new TestCaseData(typeof(short?), SchemaValueType.Integer);
+				yield return new TestCaseData(typeof(ushort?), SchemaValueType.Integer);
+				yield return new TestCaseData(typeof(int?), SchemaValueType.Integer);
+				yield return new TestCaseData(typeof(uint?), SchemaValueType.Integer);
+				yield return new TestCaseData(typeof(long?), SchemaValueType.Integer);
+				yield return new TestCaseData(typeof(ulong?), SchemaValueType.Integer);
+				yield return new TestCaseData(typeof(float?), SchemaValueType.Number);
+				yield return new TestCaseData(typeof(double?), SchemaValueType.Number);
+				yield return new TestCaseData(typeof(decimal?), SchemaValueType.Number);
 			}
 		}
 
@@ -49,6 +60,17 @@ public void IntArray()
 			AssertEqual(expected, actual);
 		}
 
+		[Test]
+		public void NullableIntArray()
+		{
+			JsonSchema expected = new JsonSchemaBuilder().Type(SchemaValueType.Array)
+				.Items(new JsonSchemaBuilder().Type(SchemaValueType.Integer));
+
+			JsonSchema actual = new JsonSchemaBuilder().FromType<int?[]>();
+
+			AssertEqual(expected, actual);
+		}
+
 		[Test]
 		// ReSharper disable once InconsistentNaming
 		public void IEnumerableOfListOfStrings()

JsonSchema.Generation/GeneratorRegistry.cs

@@ -13,6 +13,7 @@ public static class GeneratorRegistry
 		private static readonly List<ISchemaGenerator> Generators =
 			new List<ISchemaGenerator>
 			{
+				new NullableValueTypeSchemaGenerator(),
 				new BooleanSchemaGenerator(),
 				new IntegerSchemaGenerator(),
 				new NumberSchemaGenerator(),

JsonSchema.Generation/Generators/NullableValueTypeSchemaGenerator.cs

@@ -0,0 +1,22 @@
+using System;
+
+namespace Json.Schema.Generation.Generators
+{
+	internal class NullableValueTypeSchemaGenerator : ISchemaGenerator
+	{
+		public bool Handles(Type type)
+		{
+			return type.IsGenericType && type.GetGenericTypeDefinition() == typeof(Nullable<>);
+		}
+
+		public void AddConstraints(SchemaGeneratorContext context)
+		{
+			var underlyingType = Nullable.GetUnderlyingType(context.Type);
+
+			if (underlyingType == null) return;
+			var underlyingContext = SchemaGenerationContextCache.Get(underlyingType, context.Attributes, context.Configuration);
+
+			context.Intents.AddRange(underlyingContext.Intents);
+		}
+	}
+}

JsonSchema.Generation/Intents/DeprecatedIntent.cs

@@ -8,7 +8,7 @@ public class DeprecatedIntent : ISchemaKeywordIntent
 		/// <summary>
 		/// The value.
 		/// </summary>
-		public bool Value { get; }
+		public bool Value { get; set; }
 
 		/// <summary>
 		/// Creates a new <see cref="DeprecatedIntent"/> instance.

JsonSchema.Generation/Intents/EnumIntent.cs

@@ -13,7 +13,7 @@ public class EnumIntent : ISchemaKeywordIntent
 		/// <summary>
 		/// The names defined by the enumeration.
 		/// </summary>
-		public List<string> Names { get; }
+		public List<string> Names { get; set; }
 
 		/// <summary>
 		/// Applies the keyword to the <see cref="JsonSchemaBuilder"/>.

JsonSchema.Generation/Intents/ExclusiveMaximumIntent.cs

@@ -8,7 +8,7 @@ public class ExclusiveMaximumIntent : ISchemaKeywordIntent
 		/// <summary>
 		/// The value.
 		/// </summary>
-		public decimal Value { get; }
+		public decimal Value { get; set; }
 
 		/// <summary>
 		/// Creates a new <see cref="ExclusiveMaximumIntent"/> instance.

JsonSchema.Generation/Intents/ExclusiveMinimumIntent.cs

@@ -8,7 +8,7 @@ public class ExclusiveMinimumIntent : ISchemaKeywordIntent
 		/// <summary>
 		/// The value.
 		/// </summary>
-		public decimal Value { get; }
+		public decimal Value { get; set; }
 
 		/// <summary>
 		/// Creates a new <see cref="ExclusiveMinimumIntent"/> instance.

JsonSchema.Generation/Intents/FormatIntent.cs

@@ -8,7 +8,7 @@ public class FormatIntent : ISchemaKeywordIntent
 		/// <summary>
 		/// The format.
 		/// </summary>
-		public Format Format { get; }
+		public Format Format { get; set; }
 
 		/// <summary>
 		/// Creates a new <see cref="FormatIntent"/> instance.

JsonSchema.Generation/Intents/MaxItemsIntent.cs

@@ -8,7 +8,7 @@ public class MaxItemsIntent : ISchemaKeywordIntent
 		/// <summary>
 		/// The value.
 		/// </summary>
-		public uint Value { get; }
+		public uint Value { get; set; }
 
 		/// <summary>
 		/// Creates a new <see cref="MaxItemsIntent"/> instance.

JsonSchema.Generation/Intents/MaxLengthIntent.cs

@@ -8,7 +8,7 @@ public class MaxLengthIntent : ISchemaKeywordIntent
 		/// <summary>
 		/// The value.
 		/// </summary>
-		public uint Value { get; }
+		public uint Value { get; set; }
 
 		/// <summary>
 		/// Creates a new <see cref="MaxLengthIntent"/> instance.