Merge pull request #14 from mattpolzin/feature/OpenAPISchema

Just enough OpenAPI Schema stuff to be dangerous

JSONAPI.playground/Pages/OpenAPI Documentation.xcplaygroundpage/Contents.swift

@@ -3,6 +3,7 @@
 import Foundation
 import JSONAPI
 import JSONAPIOpenAPI
+import Poly
 
 // print Entity Schema
 let encoder = JSONEncoder()
@@ -28,3 +29,18 @@ print("Batch Person Document Schema")
 print("====")
 print(batchPersonSchemaData.map { String(data: $0, encoding: .utf8)! } ?? "Schema Construction Failed")
 print("====")
+
+let tmp: [String: OpenAPIComponents.SchemasDict.RefType] = [
+	"BatchPerson": try! BatchPeopleDocument.openAPINodeWithExample()
+]
+
+let components = OpenAPIComponents(schemas: tmp)
+
+let batchPeopleRef = JSONReference(type: \OpenAPIComponents.schemas, selector: "BatchPerson")
+
+let tmp2 = JSONNode.reference(batchPeopleRef)
+
+print("====")
+print("====")
+//print(String(data: try! encoder.encode(components), encoding: .utf8)!)
+print(String(data: try! encoder.encode(tmp2), encoding: .utf8)!)

Sources/JSONAPIOpenAPI/JSONAPI/JSONAPITypes+OpenAPI.swift

@@ -65,6 +65,18 @@ extension Attribute: AnyWrappedJSONCaseIterable where RawValue: AnyJSONCaseItera
 	}
 }
 
+extension Attribute: GenericOpenAPINodeType where RawValue: GenericOpenAPINodeType {
+	public static func genericOpenAPINode(using encoder: JSONEncoder) throws -> JSONNode {
+		return try RawValue.genericOpenAPINode(using: encoder)
+	}
+}
+
+extension Attribute: DateOpenAPINodeType where RawValue: DateOpenAPINodeType {
+	public static func dateOpenAPINodeGuess(using encoder: JSONEncoder) -> JSONNode? {
+		return RawValue.dateOpenAPINodeGuess(using: encoder)
+	}
+}
+
 extension TransformedAttribute: OpenAPINodeType where RawValue: OpenAPINodeType {
 	static public func openAPINode() throws -> JSONNode {
 		// If the RawValue is not required, we actually consider it
@@ -129,7 +141,7 @@ extension ToManyRelationship: OpenAPINodeType {
 	}
 }
 
-extension Entity: OpenAPIEncodedNodeType, OpenAPINodeType where Description.Attributes: Sampleable, Description.Relationships: Sampleable {
+extension Entity: OpenAPIEncodedNodeType where Description.Attributes: Sampleable, Description.Relationships: Sampleable {
 	public static func openAPINode(using encoder: JSONEncoder) throws -> JSONNode {
 		// NOTE: const for json `type` not supported by OpenAPI 3.0
 		//		Will use "enum" with one possible value for now.
@@ -172,13 +184,13 @@ extension Entity: OpenAPIEncodedNodeType, OpenAPINodeType where Description.Attr
 	}
 }
 
-extension SingleResourceBody: OpenAPIEncodedNodeType, OpenAPINodeType where Entity: OpenAPIEncodedNodeType {
+extension SingleResourceBody: OpenAPIEncodedNodeType where Entity: OpenAPIEncodedNodeType {
 	public static func openAPINode(using encoder: JSONEncoder) throws -> JSONNode {
 		return try Entity.openAPINode(using: encoder)
 	}
 }
 
-extension ManyResourceBody: OpenAPIEncodedNodeType, OpenAPINodeType where Entity: OpenAPIEncodedNodeType {
+extension ManyResourceBody: OpenAPIEncodedNodeType where Entity: OpenAPIEncodedNodeType {
 	public static func openAPINode(using encoder: JSONEncoder) throws -> JSONNode {
 		return .array(.init(format: .generic,
 							required: true),
@@ -186,7 +198,7 @@ extension ManyResourceBody: OpenAPIEncodedNodeType, OpenAPINodeType where Entity
 	}
 }
 
-extension Document: OpenAPIEncodedNodeType, OpenAPINodeType where PrimaryResourceBody: OpenAPIEncodedNodeType, IncludeType: OpenAPINodeType {
+extension Document: OpenAPIEncodedNodeType where PrimaryResourceBody: OpenAPIEncodedNodeType, IncludeType: OpenAPINodeType {
 	public static func openAPINode(using encoder: JSONEncoder) throws -> JSONNode {
 		// TODO: metadata, links, api description, errors
 		// TODO: represent data and errors as the two distinct possible outcomes
@@ -199,7 +211,7 @@ extension Document: OpenAPIEncodedNodeType, OpenAPINodeType where PrimaryResourc
 		do {
 			includeNode = try Includes<Include>.openAPINode()
 		} catch let err as OpenAPITypeError {
-			guard err == .invalidNode else {
+			guard case .invalidNode = err else {
 				throw err
 			}
 			includeNode = nil

Sources/JSONAPIOpenAPI/OpenAPI/Date+OpenAPI.swift

@@ -0,0 +1,40 @@
+//
+//  Date+OpenAPI.swift
+//  JSONAPIOpenAPI
+//
+//  Created by Mathew Polzin on 1/24/19.
+//
+
+import Foundation
+
+extension Date: DateOpenAPINodeType {
+	public static func dateOpenAPINodeGuess(using encoder: JSONEncoder) -> JSONNode? {
+
+		switch encoder.dateEncodingStrategy {
+		case .deferredToDate, .custom:
+			// I don't know if we can say anything about this case without
+			// encoding the Date and looking at it, which is what `primitiveGuess()`
+			// does.
+			return nil
+
+		case .secondsSince1970,
+			 .millisecondsSince1970:
+			return .number(.init(format: .double,
+								 required: true),
+						   .init())
+
+		case .iso8601:
+			return .string(.init(format: .dateTime,
+								 required: true),
+						   .init())
+
+		case .formatted(let formatter):
+			let hasTime = formatter.timeStyle != .none
+			let format: JSONTypeFormat.StringFormat = hasTime ? .dateTime : .date
+
+			return .string(.init(format: format,
+								 required: true),
+						   .init())
+		}
+	}
+}

Sources/JSONAPIOpenAPI/OpenAPI/OpenAPITypes+Codable.swift

@@ -155,6 +155,7 @@ extension JSONNode: Encodable {
 		case oneOf
 		case anyOf
 		case not
+		case reference = "$ref"
 	}
 
 	public func encode(to encoder: Encoder) throws {
@@ -189,6 +190,172 @@ extension JSONNode: Encodable {
 			var container = encoder.container(keyedBy: SubschemaCodingKeys.self)
 
 			try container.encode(node, forKey: .not)
+
+		case .reference(let reference):
+			var container = encoder.container(keyedBy: SubschemaCodingKeys.self)
+
+			try container.encode(reference, forKey: .reference)
+		}
+	}
+}
+
+extension JSONReference: Encodable {
+	public func encode(to encoder: Encoder) throws {
+		var container = encoder.singleValueContainer()
+
+		let referenceString: String = {
+			switch self {
+			case .file(let reference):
+				return reference
+			case .node(let reference):
+				return "#/\(Root.refName)/\(reference.refName)/\(reference.selector)"
+			}
+		}()
+
+		try container.encode(referenceString)
+	}
+}
+
+extension RefDict: Encodable {
+	public func encode(to encoder: Encoder) throws {
+		var container = encoder.singleValueContainer()
+
+		try container.encode(dict)
+	}
+}
+
+extension OpenAPIResponse.Code: Encodable {
+	public func encode(to encoder: Encoder) throws {
+		var container = encoder.singleValueContainer()
+
+		let string: String
+		switch self {
+		case .`default`:
+			string = "default"
+
+		case .status(code: let code):
+			string = String(code)
+		}
+
+		try container.encode(string)
+	}
+}
+
+extension OpenAPIPathItem.PathProperties.Operation: Encodable {
+	private enum CodingKeys: String, CodingKey {
+		case tags
+		case summary
+		case description
+		case externalDocs
+		case operationId
+		case parameters
+		case requestBody
+		case responses
+		case callbacks
+		case deprecated
+		case security
+		case servers
+	}
+
+	public func encode(to encoder: Encoder) throws {
+		var container = encoder.container(keyedBy: CodingKeys.self)
+
+		if tags != nil {
+			try container.encode(tags, forKey: .tags)
+		}
+
+		if summary != nil {
+			try container.encode(summary, forKey: .summary)
+		}
+
+		if description != nil {
+			try container.encode(description, forKey: .description)
+		}
+
+		try container.encode(operationId, forKey: .operationId)
+
+		try container.encode(parameters, forKey: .parameters)
+
+		try container.encode(responses, forKey: .responses)
+
+		try container.encode(deprecated, forKey: .deprecated)
+	}
+}
+
+extension OpenAPIPathItem.PathProperties: Encodable {
+	private enum CodingKeys: String, CodingKey {
+		case summary
+		case description
+		case servers
+		case parameters
+
+		case get
+		case put
+		case post
+		case delete
+		case options
+		case head
+		case patch
+		case trace
+	}
+
+	public func encode(to encoder: Encoder) throws {
+		var container = encoder.container(keyedBy: CodingKeys.self)
+
+		if summary != nil {
+			try container.encode(summary, forKey: .summary)
+		}
+
+		if description != nil {
+			try container.encode(description, forKey: .description)
+		}
+
+		try container.encode(parameters, forKey: .parameters)
+
+		if get != nil {
+			try container.encode(get, forKey: .get)
+		}
+
+		if put != nil {
+			try container.encode(put, forKey: .put)
+		}
+
+		if post != nil {
+			try container.encode(post, forKey: .post)
+		}
+
+		if delete != nil {
+			try container.encode(delete, forKey: .delete)
+		}
+
+		if options != nil {
+			try container.encode(options, forKey: .options)
+		}
+
+		if head != nil {
+			try container.encode(head, forKey: .head)
+		}
+
+		if patch != nil {
+			try container.encode(patch, forKey: .patch)
+		}
+
+		if trace != nil {
+			try container.encode(trace, forKey: .trace)
+		}
+	}
+}
+
+extension OpenAPIPathItem: Encodable {
+	public func encode(to encoder: Encoder) throws {
+		var container = encoder.singleValueContainer()
+
+		switch self {
+		case .reference(let reference):
+			try container.encode(reference)
+
+		case .operations(let operations):
+			try container.encode(operations)
 		}
 	}
 }

Sources/JSONAPIOpenAPI/OpenAPI/OpenAPITypes.swift

@@ -7,6 +7,7 @@
 
 import AnyCodable
 import Foundation
+import Poly
 
 // MARK: Node (i.e. schema) Protocols
 
@@ -16,22 +17,16 @@ public protocol OpenAPINodeType {
 	static func openAPINode() throws -> JSONNode
 }
 
-extension OpenAPINodeType where Self: Sampleable, Self: Encodable {
-	public static func openAPINodeWithExample(using encoder: JSONEncoder = JSONEncoder()) throws -> JSONNode {
-		return try openAPINode().with(example: Self.successSample ?? Self.sample, using: encoder)
-	}
-}
-
 /// Anything conforming to `OpenAPIEncodedNodeType` can provide an
 /// OpenAPI schema representing itself but it may need an Encoder
 /// to do its job.
-public protocol OpenAPIEncodedNodeType: OpenAPINodeType {
+public protocol OpenAPIEncodedNodeType {
 	static func openAPINode(using encoder: JSONEncoder) throws -> JSONNode
 }
 
-extension OpenAPIEncodedNodeType {
-	public static func openAPINode() throws -> JSONNode {
-		return try openAPINode(using: JSONEncoder())
+extension OpenAPIEncodedNodeType where Self: Sampleable, Self: Encodable {
+	public static func openAPINodeWithExample(using encoder: JSONEncoder = JSONEncoder()) throws -> JSONNode {
+		return try openAPINode(using: encoder).with(example: Self.successSample ?? Self.sample, using: encoder)
 	}
 }
 
@@ -74,6 +69,12 @@ public protocol GenericOpenAPINodeType {
 	static func genericOpenAPINode(using encoder: JSONEncoder) throws -> JSONNode
 }
 
+/// Anything conforming to `DateOpenAPINodeType` is
+/// able to attempt to represent itself as a date OpenAPINode
+public protocol DateOpenAPINodeType {
+	static func dateOpenAPINodeGuess(using encoder: JSONEncoder) -> JSONNode?
+}
+
 /// Anything conforming to `AnyJSONCaseIterable` can provide a
 /// list of its possible values.
 public protocol AnyJSONCaseIterable {
@@ -268,6 +269,7 @@ public enum JSONNode: Equatable {
 	indirect case one(of: [JSONNode])
 	indirect case any(of: [JSONNode])
 	indirect case not(JSONNode)
+	case reference(JSONReference<OpenAPIComponents, JSONNode>)
 
 	public struct Context<Format: OpenAPIFormat>: JSONNodeContext, Equatable {
 		public let format: Format
@@ -470,7 +472,7 @@ public enum JSONNode: Equatable {
 			return .integer(context.format)
 		case .string(let context, _):
 			return .string(context.format)
-		case .all, .one, .any, .not:
+		case .all, .one, .any, .not, .reference:
 			return nil
 		}
 	}
@@ -484,7 +486,7 @@ public enum JSONNode: Equatable {
 			 .integer(let contextA as JSONNodeContext, _),
 			 .string(let contextA as JSONNodeContext, _):
 			return contextA.required
-		case .all, .one, .any, .not:
+		case .all, .one, .any, .not, .reference:
 			return true
 		}
 	}
@@ -504,7 +506,7 @@ public enum JSONNode: Equatable {
 			return .integer(context.optionalContext(), contextB)
 		case .string(let context, let contextB):
 			return .string(context.optionalContext(), contextB)
-		case .all, .one, .any, .not:
+		case .all, .one, .any, .not, .reference:
 			return self
 		}
 	}
@@ -524,7 +526,7 @@ public enum JSONNode: Equatable {
 			return .integer(context.requiredContext(), contextB)
 		case .string(let context, let contextB):
 			return .string(context.requiredContext(), contextB)
-		case .all, .one, .any, .not:
+		case .all, .one, .any, .not, .reference:
 			return self
 		}
 	}
@@ -544,7 +546,7 @@ public enum JSONNode: Equatable {
 			return .integer(context.nullableContext(), contextB)
 		case .string(let context, let contextB):
 			return .string(context.nullableContext(), contextB)
-		case .all, .one, .any, .not:
+		case .all, .one, .any, .not, .reference:
 			return self
 		}
 	}
@@ -564,7 +566,7 @@ public enum JSONNode: Equatable {
 			return .integer(context.with(allowedValues: allowedValues), contextB)
 		case .string(let context, let contextB):
 			return .string(context.with(allowedValues: allowedValues), contextB)
-		case .all, .one, .any, .not:
+		case .all, .one, .any, .not, .reference:
 			return self
 		}
 	}
@@ -591,7 +593,7 @@ public enum JSONNode: Equatable {
 			return .integer(context.with(example: example, using: encoder), contextB)
 		case .string(let context, let contextB):
 			return .string(context.with(example: example, using: encoder), contextB)
-		case .all, .one, .any, .not:
+		case .all, .one, .any, .not, .reference:
 			return self
 		}
 	}
@@ -603,6 +605,320 @@ public enum OpenAPICodableError: Swift.Error, Equatable {
 	case primitiveGuessFailed
 }
 
-public enum OpenAPITypeError: Swift.Error, Equatable {
+public enum OpenAPITypeError: Swift.Error {
 	case invalidNode
+	case unknownNodeType(Any.Type)
+}
+
+/// Anything conforming to RefName knows what to call itself
+/// in the context of JSON References.
+public protocol RefName {
+	static var refName: String { get }
+}
+
+public protocol ReferenceRoot: RefName {}
+
+public protocol ReferenceDict: RefName {
+	associatedtype Value
+}
+
+/// A RefDict knows what to call itself (Name) and where to
+/// look for itself (Root) and it stores a dictionary of
+/// JSONNodes (some of which might be other references).
+public struct RefDict<Root: ReferenceRoot, Name: RefName, RefType: Equatable & Encodable>: ReferenceDict, Equatable {
+	public static var refName: String { return Name.refName }
+
+	public typealias Value = RefType
+	public typealias Key = String
+
+	let dict: [String: RefType]
+
+	public init(_ dict: [String: RefType]) {
+		self.dict = dict
+	}
+
+	public subscript(_ key: String) -> RefType? {
+		return dict[key]
+	}
+}
+
+/// A Reference is the combination of
+/// a path to a reference dictionary
+/// and a selector that the dictionary is keyed off of.
+public enum JSONReference<Root: ReferenceRoot, RefType: Equatable>: Equatable {
+
+	case node(InternalReference)
+	case file(FileReference)
+
+	public typealias FileReference = String
+
+	public struct InternalReference: Equatable {
+		public let path: PartialKeyPath<Root>
+		public let selector: String
+
+		public var refName: String {
+			// we require RD be a RefName in the initializer
+			// so it is safe to force cast here.
+			return (type(of: path).valueType as! RefName.Type).refName
+		}
+
+		public init<RD: RefName & ReferenceDict>(type: KeyPath<Root, RD>,
+										selector: String) where RD.Value == RefType {
+			self.path = type
+			self.selector = selector
+		}
+	}
+}
+
+/// An OpenAPI Path Item
+/// This type describes the endpoints a server has
+/// bound to a particular path.
+public enum OpenAPIPathItem: Equatable {
+	case reference(JSONReference<OpenAPIComponents, OpenAPIPathItem>)
+	case operations(PathProperties)
+
+	public struct PathProperties: Equatable {
+		public let summary: String?
+		public let description: String?
+//		public let servers:
+		public let parameters: ParameterArray
+
+		public let get: Operation?
+		public let put: Operation?
+		public let post: Operation?
+		public let delete: Operation?
+		public let options: Operation?
+		public let head: Operation?
+		public let patch: Operation?
+		public let trace: Operation?
+
+		public init(summary: String? = nil,
+					description: String? = nil,
+					parameters: ParameterArray,
+					get: Operation? = nil,
+					put: Operation? = nil,
+					post: Operation? = nil,
+					delete: Operation? = nil,
+					options: Operation? = nil,
+					head: Operation? = nil,
+					patch: Operation? = nil,
+					trace: Operation? = nil) {
+			self.summary = summary
+			self.description = description
+			self.parameters = parameters
+
+			self.get = get
+			self.put = put
+			self.post = post
+			self.delete = delete
+			self.options = options
+			self.head = head
+			self.patch = patch
+			self.trace = trace
+		}
+
+		public typealias ParameterArray = [Either<Parameter, JSONReference<OpenAPIComponents, Parameter>>]
+
+		public struct Parameter: Equatable, Encodable {
+			private enum CodingKeys: String, CodingKey {
+				case name
+//				case parameterLocation = "in"
+				case description
+				case deprecated
+			}
+
+			public let name: String
+//			public let parameterLocation: Location
+			public let description: String?
+			public let deprecated: Bool // default is false
+			// TODO: serialization rules
+			/*
+			Serialization Rules
+			*/
+
+			public init(name: String,
+						description: String? = nil,
+						deprecated: Bool = false) {
+				self.name = name
+				self.description = description
+				self.deprecated = deprecated
+			}
+
+//			public enum Location: Encodable {
+//				case query(required: Bool?)
+//				case header(required: Bool?)
+//				case path
+//				case cookie(required: Bool?)
+//			}
+		}
+
+		public struct Operation: Equatable {
+			public let tags: [String]?
+			public let summary: String?
+			public let description: String?
+//			public let externalDocs:
+			public let operationId: String
+			public let parameters: ParameterArray
+//			public let requestBody:
+			public let responses: ResponseMap
+//			public let callbacks:
+			public let deprecated: Bool // default is false
+//			public let security:
+//			public let servers:
+
+			public init(tags: [String]? = nil,
+						summary: String? = nil,
+						description: String? = nil,
+						operationId: String,
+						parameters: ParameterArray,
+						responses: ResponseMap,
+						deprecated: Bool = false) {
+				self.tags = tags
+				self.summary = summary
+				self.description = description
+				self.operationId = operationId
+				self.parameters = parameters
+				self.responses = responses
+				self.deprecated = deprecated
+			}
+
+			public typealias ResponseMap = [OpenAPIResponse.Code: Either<OpenAPIResponse, JSONReference<OpenAPIComponents, OpenAPIResponse>>]
+		}
+	}
+}
+
+public struct OpenAPIResponse: Encodable, Equatable {
+	public let description: String
+//	public let headers:
+	public let content: ContentMap
+//	public let links:
+
+	public init(description: String,
+				content: ContentMap) {
+		self.description = description
+		self.content = content
+	}
+
+	public typealias ContentMap = [ContentType: Content]
+
+	public enum Code: Equatable, Hashable {
+		case `default`
+		case status(code: Int)
+	}
+
+	public enum ContentType: String, Encodable, Equatable, Hashable {
+		case json = "application/json"
+	}
+
+	public struct Content: Encodable, Equatable {
+		public let schema: Either<JSONNode, JSONReference<OpenAPIComponents, JSONNode>>
+//		public let example:
+//		public let examples:
+//		public let encoding:
+
+		public init(schema: Either<JSONNode, JSONReference<OpenAPIComponents, JSONNode>>) {
+			self.schema = schema
+		}
+	}
+}
+
+/// What the spec calls the "Components Object".
+/// This is a place to put reusable components to
+/// be referenced from other parts of the spec.
+public struct OpenAPIComponents: Equatable, Encodable, ReferenceRoot {
+	public static var refName: String { return "components" }
+
+	public let schemas: SchemasDict
+//	public let responses:
+	public let parameters: ParametersDict
+//	public let examples:
+//	public let requestBodies:
+//	public let headers:
+//	public let headers:
+//	public let securitySchemas:
+//	public let links:
+//	public let callbacks:
+
+	public init(schemas: [String: SchemasDict.Value], parameters: [String: ParametersDict.Value]) {
+		self.schemas = SchemasDict(schemas)
+		self.parameters = ParametersDict(parameters)
+	}
+
+	public enum SchemasName: RefName {
+		public static var refName: String { return "schemas" }
+	}
+
+	public typealias SchemasDict = RefDict<OpenAPIComponents, SchemasName, JSONNode>
+
+	public enum ParametersName: RefName {
+		public static var refName: String { return "parameters" }
+	}
+
+	public typealias ParametersDict = RefDict<OpenAPIComponents, ParametersName, OpenAPIPathItem.PathProperties.Parameter>
+}
+
+/// The root of an OpenAPI 3.0 document.
+public struct OpenAPISchema: Encodable {
+	private enum CodingKeys: String, CodingKey {
+		case openAPIVersion = "openapi"
+		case info
+		case paths
+		case components
+	}
+
+	public let openAPIVersion: Version
+	public let info: Info
+//	public let servers:
+	public let paths: [PathComponents: OpenAPIPathItem]
+	public let components: OpenAPIComponents
+//	public let security:
+//	public let tags:
+//	public let externalDocs:
+
+	public init(openAPIVersion: Version = .v3_0_0,
+				info: Info,
+				paths: [PathComponents: OpenAPIPathItem],
+				components: OpenAPIComponents) {
+		self.openAPIVersion = openAPIVersion
+		self.info = info
+		self.paths = paths
+		self.components = components
+	}
+
+	public enum Version: String, Encodable {
+		case v3_0_0 = "3.0.0"
+	}
+
+	public struct Info: Encodable {
+		public let title: String
+		public let description: String?
+		public let termsOfService: URL?
+//		public let contact:
+//		public let license:
+		public let version: String
+
+		public init(title: String,
+					description: String? = nil,
+					termsOfService: URL? = nil,
+					version: String) {
+			self.title = title
+			self.description = description
+			self.termsOfService = termsOfService
+			self.version = version
+		}
+	}
+
+	public struct PathComponents: Encodable, Equatable, Hashable {
+		public let components: [String]
+
+		public init(_ components: [String]) {
+			self.components = components
+		}
+
+		public func encode(to encoder: Encoder) throws {
+			var container = encoder.singleValueContainer()
+
+			try container.encode(components.joined(separator: "/"))
+		}
+	}
 }

Sources/JSONAPIOpenAPI/Sampleable/JSONAPI+Sampleable.swift

@@ -0,0 +1,68 @@
+//
+//  JSONAPI+Sampleable.swift
+//  JSONAPIOpenAPI
+//
+//  Created by Mathew Polzin on 1/24/19.
+//
+
+import JSONAPI
+
+extension NoAttributes: Sampleable {
+	public static var sample: NoAttributes {
+		return .none
+	}
+}
+
+extension NoRelationships: Sampleable {
+	public static var sample: NoRelationships {
+		return .none
+	}
+}
+
+extension NoMetadata: Sampleable {
+	public static var sample: NoMetadata {
+		return .none
+	}
+}
+
+extension NoLinks: Sampleable {
+	public static var sample: NoLinks {
+		return .none
+	}
+}
+
+extension NoAPIDescription: Sampleable {
+	public static var sample: NoAPIDescription {
+		return .none
+	}
+}
+
+extension UnknownJSONAPIError: Sampleable {
+	public static var sample: UnknownJSONAPIError {
+		return .unknownError
+	}
+}
+
+extension Unidentified: Sampleable {
+	public static var sample: Unidentified {
+		return Unidentified()
+	}
+}
+
+extension Attribute: Sampleable where RawValue: Sampleable {
+	public static var sample: Attribute<RawValue> {
+		return .init(value: RawValue.sample)
+	}
+}
+
+extension SingleResourceBody: Sampleable where Entity: Sampleable {
+	public static var sample: SingleResourceBody<Entity> {
+		return .init(entity: Entity.sample)
+	}
+}
+
+extension ManyResourceBody: Sampleable where Entity: Sampleable {
+	public static var sample: ManyResourceBody<Entity> {
+		return .init(entities: Entity.samples)
+	}
+}

Sources/JSONAPIOpenAPI/Sampleable/Sampleable+OpenAPI.swift

@@ -0,0 +1,161 @@
+//
+//  Sampleable+OpenAPI.swift
+//  JSONAPIOpenAPI
+//
+//  Created by Mathew Polzin on 1/24/19.
+//
+
+import Foundation
+import AnyCodable
+
+public typealias SampleableOpenAPIType = Sampleable & GenericOpenAPINodeType
+
+extension Sampleable where Self: Encodable {
+	public static func genericOpenAPINode(using encoder: JSONEncoder) throws -> JSONNode {
+
+		// short circuit for dates
+		if let dateType = self as? Date.Type,
+			let node = try dateType.dateOpenAPINodeGuess(using: encoder) ?? primitiveGuess(using: encoder) {
+			return node
+		}
+
+		let mirror = Mirror(reflecting: Self.sample)
+		let properties: [(String, JSONNode)] = try mirror.children.compactMap { child in
+
+			// see if we can enumerate the possible values
+			let maybeAllCases: [AnyCodable]? = {
+				switch type(of: child.value) {
+				case let valType as AnyJSONCaseIterable.Type:
+					return valType.allCases(using: encoder)
+				case let valType as AnyWrappedJSONCaseIterable.Type:
+					return valType.allCases(using: encoder)
+				default:
+					return nil
+				}
+			}()
+
+			// try to snag an OpenAPI Node
+			let maybeOpenAPINode: JSONNode? = try {
+				switch type(of: child.value) {
+				case let valType as OpenAPINodeType.Type:
+					return try valType.openAPINode()
+
+				case let valType as RawOpenAPINodeType.Type:
+					return try valType.rawOpenAPINode()
+
+				case let valType as WrappedRawOpenAPIType.Type:
+					return try valType.wrappedOpenAPINode()
+
+				case let valType as DoubleWrappedRawOpenAPIType.Type:
+					return try valType.wrappedOpenAPINode()
+
+				case let valType as GenericOpenAPINodeType.Type:
+					return try valType.genericOpenAPINode(using: encoder)
+
+				case let valType as DateOpenAPINodeType.Type:
+					return valType.dateOpenAPINodeGuess(using: encoder)
+
+				default:
+					throw OpenAPITypeError.unknownNodeType(self)
+//					return nil
+				}
+				}()
+
+			// put it all together
+			let newNode: JSONNode?
+			if let allCases = maybeAllCases,
+				let openAPINode = maybeOpenAPINode {
+				newNode = try openAPINode.with(allowedValues: allCases)
+			} else {
+				newNode = maybeOpenAPINode
+			}
+
+			return zip(child.label, newNode) { ($0, $1) }
+		}
+
+		// if there are no properties, let's see if we are dealing
+		// with a primitive.
+		if properties.count == 0,
+			let primitive = try primitiveGuess(using: encoder) {
+			return primitive
+		}
+
+		// There should not be any duplication of keys since these are
+		// property names, but rather than risk runtime exception, we just
+		// fail to the newer value arbitrarily
+		let propertiesDict = Dictionary(properties) { _, value2 in value2 }
+
+		return .object(.init(format: .generic,
+							 required: true),
+					   .init(properties: propertiesDict))
+	}
+
+	private static func primitiveGuess(using encoder: JSONEncoder) throws -> JSONNode? {
+
+		let data = try encoder.encode(PrimitiveWrapper(primitive: Self.sample))
+		let wrappedValue = try JSONSerialization.jsonObject(with: data, options: [.allowFragments])
+
+		guard let wrapperDict = wrappedValue as? [String: Any],
+			wrapperDict.contains(where: { $0.key == "primitive" }) else {
+				throw OpenAPICodableError.primitiveGuessFailed
+		}
+
+		let value = (wrappedValue as! [String: Any])["primitive"]!
+
+		return try {
+			switch type(of: value) {
+			case let valType as OpenAPINodeType.Type:
+				return try valType.openAPINode()
+
+			case let valType as RawOpenAPINodeType.Type:
+				return try valType.rawOpenAPINode()
+
+			case let valType as WrappedRawOpenAPIType.Type:
+				return try valType.wrappedOpenAPINode()
+
+			case let valType as DoubleWrappedRawOpenAPIType.Type:
+				return try valType.wrappedOpenAPINode()
+
+			case let valType as GenericOpenAPINodeType.Type:
+				return try valType.genericOpenAPINode(using: encoder)
+
+			case let valType as DateOpenAPINodeType.Type:
+				return valType.dateOpenAPINodeGuess(using: encoder)
+
+			default:
+				return nil
+			}
+			}() ?? {
+				switch value {
+				case is String:
+					return .string(.init(format: .generic,
+										 required: true),
+								   .init())
+
+				case is Int:
+					return .integer(.init(format: .generic,
+										  required: true),
+									.init())
+
+				case is Double:
+					return .number(.init(format: .double,
+										 required: true),
+								   .init())
+
+				case is Bool:
+					return .boolean(.init(format: .generic,
+										  required: true))
+
+				default:
+					return nil
+				}
+			}()
+	}
+}
+
+// The following wrapper is only needed because JSONEncoder cannot yet encode
+// JSON fragments. It is a very unfortunate limitation that requires silly
+// workarounds in edge cases like this.
+private struct PrimitiveWrapper<Wrapped: Encodable>: Encodable {
+	let primitive: Wrapped
+}

Sources/JSONAPIOpenAPI/Sampleable/Sampleable.swift

@@ -5,9 +5,7 @@
 //  Created by Mathew Polzin on 1/15/19.
 //
 
-import JSONAPI
 import Foundation
-import AnyCodable
 
 /// A Sampleable type can provide a sample value.
 /// This is useful for reflection.
@@ -37,8 +35,6 @@ public protocol Sampleable {
 	static var samples: [Self] { get }
 }
 
-public typealias SampleableOpenAPIType = Sampleable & GenericOpenAPINodeType
-
 public extension Sampleable {
 	// default implementation:
 	public static var successSample: Self? { return nil }
@@ -50,141 +46,6 @@ public extension Sampleable {
 	public static var samples: [Self] { return [Self.sample] }
 }
 
-extension Sampleable where Self: Encodable {
-	public static func genericOpenAPINode(using encoder: JSONEncoder) throws -> JSONNode {
-		let mirror = Mirror(reflecting: Self.sample)
-		let properties: [(String, JSONNode)] = try mirror.children.compactMap { child in
-
-			// see if we can enumerate the possible values
-			let maybeAllCases: [AnyCodable]? = {
-				switch type(of: child.value) {
-				case let valType as AnyJSONCaseIterable.Type:
-					return valType.allCases(using: encoder)
-				case let valType as AnyWrappedJSONCaseIterable.Type:
-					return valType.allCases(using: encoder)
-				default:
-					return nil
-				}
-			}()
-
-			// try to snag an OpenAPI Node
-			let maybeOpenAPINode: JSONNode? = try {
-				switch type(of: child.value) {
-				case let valType as OpenAPINodeType.Type:
-					return try valType.openAPINode()
-
-				case let valType as RawOpenAPINodeType.Type:
-					return try valType.rawOpenAPINode()
-
-				case let valType as WrappedRawOpenAPIType.Type:
-					return try valType.wrappedOpenAPINode()
-
-				case let valType as DoubleWrappedRawOpenAPIType.Type:
-					return try valType.wrappedOpenAPINode()
-
-				case let valType as GenericOpenAPINodeType.Type:
-					return try valType.genericOpenAPINode(using: encoder)
-
-				default:
-					return nil
-				}
-			}()
-
-			// put it all together
-			let newNode: JSONNode?
-			if let allCases = maybeAllCases,
-				let openAPINode = maybeOpenAPINode {
-				newNode = try openAPINode.with(allowedValues: allCases)
-			} else {
-				newNode = maybeOpenAPINode
-			}
-
-			return zip(child.label, newNode) { ($0, $1) }
-		}
-
-		// if there are no properties, let's see if we are dealing
-		// with a primitive.
-		if properties.count == 0,
-			let primitive = try primitiveGuess(using: encoder) {
-			return primitive
-		}
-
-		// There should not be any duplication of keys since these are
-		// property names, but rather than risk runtime exception, we just
-		// fail to the newer value arbitrarily
-		let propertiesDict = Dictionary(properties) { _, value2 in value2 }
-
-		return .object(.init(format: .generic,
-							 required: true),
-					   .init(properties: propertiesDict))
-	}
-
-	private static func primitiveGuess(using encoder: JSONEncoder) throws -> JSONNode? {
-		let data = try encoder.encode(PrimitiveWrapper(primitive: Self.sample))
-		let wrappedValue = try JSONSerialization.jsonObject(with: data, options: [.allowFragments])
-
-		guard let wrapperDict = wrappedValue as? [String: Any],
-			wrapperDict.contains(where: { $0.key == "primitive" }) else {
-			throw OpenAPICodableError.primitiveGuessFailed
-		}
-
-		let value = (wrappedValue as! [String: Any])["primitive"]!
-
-		return try {
-			switch type(of: value) {
-			case let valType as OpenAPINodeType.Type:
-				return try valType.openAPINode()
-
-			case let valType as RawOpenAPINodeType.Type:
-				return try valType.rawOpenAPINode()
-
-			case let valType as WrappedRawOpenAPIType.Type:
-				return try valType.wrappedOpenAPINode()
-
-			case let valType as DoubleWrappedRawOpenAPIType.Type:
-				return try valType.wrappedOpenAPINode()
-
-			case let valType as GenericOpenAPINodeType.Type:
-				return try valType.genericOpenAPINode(using: encoder)
-
-			default:
-				return nil
-			}
-		}() ?? {
-			switch value {
-			case is String:
-				return .string(.init(format: .generic,
-									 required: true),
-							   .init())
-
-			case is Int:
-				return .integer(.init(format: .generic,
-									  required: true),
-								.init())
-
-			case is Double:
-				return .number(.init(format: .double,
-									 required: true),
-							   .init())
-
-			case is Bool:
-				return .boolean(.init(format: .generic,
-									  required: true))
-
-			default:
-				return nil
-			}
-		}()
-	}
-}
-
-// The following wrapper is only needed because JSONEncoder cannot yet encode
-// JSON fragments. It is a very unfortunate limitation that requires silly
-// workarounds in edge cases like this.
-private struct PrimitiveWrapper<Wrapped: Encodable>: Encodable {
-	let primitive: Wrapped
-}
-
 extension Sampleable {
 	public static func samples<S1: Sampleable>(using s1: S1.Type, with constructor: (S1) -> Self) -> [Self] {
 		return S1.samples.map(constructor)
@@ -239,57 +100,3 @@ extension Sampleable {
 		return zip(a, zip(b, zip(c, zip(d, e)))).map { arg in (arg.0, arg.1.0, arg.1.1.0, arg.1.1.1.0, arg.1.1.1.1) }
 	}
 }
-
-extension NoAttributes: Sampleable {
-	public static var sample: NoAttributes {
-		return .none
-	}
-}
-
-extension NoRelationships: Sampleable {
-	public static var sample: NoRelationships {
-		return .none
-	}
-}
-
-extension NoMetadata: Sampleable {
-	public static var sample: NoMetadata {
-		return .none
-	}
-}
-
-extension NoLinks: Sampleable {
-	public static var sample: NoLinks {
-		return .none
-	}
-}
-
-extension NoAPIDescription: Sampleable {
-	public static var sample: NoAPIDescription {
-		return .none
-	}
-}
-
-extension UnknownJSONAPIError: Sampleable {
-	public static var sample: UnknownJSONAPIError {
-		return .unknownError
-	}
-}
-
-extension Attribute: Sampleable where RawValue: Sampleable {
-	public static var sample: Attribute<RawValue> {
-		return .init(value: RawValue.sample)
-	}
-}
-
-extension SingleResourceBody: Sampleable where Entity: Sampleable {
-	public static var sample: SingleResourceBody<Entity> {
-		return .init(entity: Entity.sample)
-	}
-}
-
-extension ManyResourceBody: Sampleable where Entity: Sampleable {
-	public static var sample: ManyResourceBody<Entity> {
-		return .init(entities: Entity.samples)
-	}
-}

Tests/JSONAPIOpenAPITests/JSONAPIAttributeOpenAPITests.swift

@@ -508,6 +508,45 @@ extension JSONAPIAttributeOpenAPITests {
 // MARK: - Date
 extension JSONAPIAttributeOpenAPITests {
 	func test_DateStringAttribute() {
+		// TEST:
+		// Encoder is set to use
+		// formatter with date
+		// with no time.
+
+		let dateFormatter = DateFormatter()
+		dateFormatter.dateStyle = .medium
+		dateFormatter.timeStyle = .none
+		dateFormatter.locale = Locale(identifier: "en_US")
+
+		let encoder = JSONEncoder()
+		encoder.outputFormatting = .prettyPrinted
+		encoder.dateEncodingStrategy = .formatted(dateFormatter)
+
+		let node = Attribute<Date>.dateOpenAPINodeGuess(using: encoder)
+
+		XCTAssertNotNil(node)
+
+		XCTAssertTrue(node?.required ?? false)
+		XCTAssertEqual(node?.jsonTypeFormat, .string(.date))
+
+		guard case .string(let contextA, let stringContext)? = node else {
+			XCTFail("Expected string Node")
+			return
+		}
+
+		XCTAssertEqual(contextA, .init(format: .date,
+									   required: true,
+									   nullable: false,
+									   allowedValues: nil))
+
+		XCTAssertEqual(stringContext, .init())
+	}
+
+	func test_DateStringAttribute_Sampleable() {
+		// TEST:
+		// Encoder is set to use
+		// formatter with date
+		// with no time.
 
 		let dateFormatter = DateFormatter()
 		dateFormatter.dateStyle = .medium
@@ -521,14 +560,14 @@ extension JSONAPIAttributeOpenAPITests {
 		let node = try! Attribute<Date>.genericOpenAPINode(using: encoder)
 
 		XCTAssertTrue(node.required)
-		XCTAssertEqual(node.jsonTypeFormat, .string(.generic))
+		XCTAssertEqual(node.jsonTypeFormat, .string(.date))
 
 		guard case .string(let contextA, let stringContext) = node else {
 			XCTFail("Expected string Node")
 			return
 		}
 
-		XCTAssertEqual(contextA, .init(format: .generic,
+		XCTAssertEqual(contextA, .init(format: .date,
 									   required: true,
 									   nullable: false,
 									   allowedValues: nil))
@@ -536,17 +575,215 @@ extension JSONAPIAttributeOpenAPITests {
 		XCTAssertEqual(stringContext, .init())
 	}
 
-	func test_DateNumberAttribute() {
+	func test_DateTimeStringAttribute() {
+		// TEST:
+		// Encoder is set to use
+		// formatter with date
+		// with time.
 
 		let dateFormatter = DateFormatter()
 		dateFormatter.dateStyle = .medium
-		dateFormatter.timeStyle = .none
+		dateFormatter.timeStyle = .short
 		dateFormatter.locale = Locale(identifier: "en_US")
 
+		let encoder = JSONEncoder()
+		encoder.outputFormatting = .prettyPrinted
+		encoder.dateEncodingStrategy = .formatted(dateFormatter)
+
+		let node = Attribute<Date>.dateOpenAPINodeGuess(using: encoder)
+
+		XCTAssertNotNil(node)
+
+		XCTAssertTrue(node?.required ?? false)
+		XCTAssertEqual(node?.jsonTypeFormat, .string(.dateTime))
+
+		guard case .string(let contextA, let stringContext)? = node else {
+			XCTFail("Expected string Node")
+			return
+		}
+
+		XCTAssertEqual(contextA, .init(format: .dateTime,
+									   required: true,
+									   nullable: false,
+									   allowedValues: nil))
+
+		XCTAssertEqual(stringContext, .init())
+	}
+
+	func test_DateTimeStringAttribute_Sampleable() {
+		// TEST:
+		// Encoder is set to use
+		// formatter with date
+		// with time.
+
+		let dateFormatter = DateFormatter()
+		dateFormatter.dateStyle = .medium
+		dateFormatter.timeStyle = .short
+		dateFormatter.locale = Locale(identifier: "en_US")
+
+		let encoder = JSONEncoder()
+		encoder.outputFormatting = .prettyPrinted
+		encoder.dateEncodingStrategy = .formatted(dateFormatter)
+
+		let node = try! Attribute<Date>.genericOpenAPINode(using: encoder)
+
+		XCTAssertTrue(node.required)
+		XCTAssertEqual(node.jsonTypeFormat, .string(.dateTime))
+
+		guard case .string(let contextA, let stringContext) = node else {
+			XCTFail("Expected string Node")
+			return
+		}
+
+		XCTAssertEqual(contextA, .init(format: .dateTime,
+									   required: true,
+									   nullable: false,
+									   allowedValues: nil))
+
+		XCTAssertEqual(stringContext, .init())
+	}
+
+	func test_8601DateStringAttribute() {
+		if #available(OSX 10.12, *) {
+			// TEST:
+			// Encoder is set to use
+			// iso8601 date format
+
+			let encoder = JSONEncoder()
+			encoder.outputFormatting = .prettyPrinted
+			encoder.dateEncodingStrategy = .iso8601
+
+			let node = Attribute<Date>.dateOpenAPINodeGuess(using: encoder)
+
+			XCTAssertNotNil(node)
+
+			XCTAssertTrue(node?.required ?? false)
+			XCTAssertEqual(node?.jsonTypeFormat, .string(.dateTime))
+
+			guard case .string(let contextA, let stringContext)? = node else {
+				XCTFail("Expected string Node")
+				return
+			}
+
+			XCTAssertEqual(contextA, .init(format: .dateTime,
+										   required: true,
+										   nullable: false,
+										   allowedValues: nil))
+
+			XCTAssertEqual(stringContext, .init())
+		}
+	}
+
+	func test_8601DateStringAttribute_Sampleable() {
+		if #available(OSX 10.12, *) {
+			// TEST:
+			// Encoder is set to use
+			// iso8601 date format
+
+			let encoder = JSONEncoder()
+			encoder.outputFormatting = .prettyPrinted
+			encoder.dateEncodingStrategy = .iso8601
+
+			let node = try! Attribute<Date>.genericOpenAPINode(using: encoder)
+
+			XCTAssertTrue(node.required)
+			XCTAssertEqual(node.jsonTypeFormat, .string(.dateTime))
+
+			guard case .string(let contextA, let stringContext) = node else {
+				XCTFail("Expected string Node")
+				return
+			}
+
+			XCTAssertEqual(contextA, .init(format: .dateTime,
+										   required: true,
+										   nullable: false,
+										   allowedValues: nil))
+
+			XCTAssertEqual(stringContext, .init())
+		}
+	}
+
+	func test_DateNumberAttribute() {
+		// TEST:
+		// Encoder is set to use
+		// seconds since 1970 as
+		// date format
+
 		let encoder = JSONEncoder()
 		encoder.outputFormatting = .prettyPrinted
 		encoder.dateEncodingStrategy = .secondsSince1970
 
+		let node = Attribute<Date>.dateOpenAPINodeGuess(using: encoder)
+
+		XCTAssertNotNil(node)
+
+		XCTAssertTrue(node?.required ?? false)
+		XCTAssertEqual(node?.jsonTypeFormat, .number(.double))
+
+		guard case .number(let contextA, let numberContext)? = node else {
+			XCTFail("Expected string Node")
+			return
+		}
+
+		XCTAssertEqual(contextA, .init(format: .double,
+									   required: true,
+									   nullable: false,
+									   allowedValues: nil))
+
+		XCTAssertEqual(numberContext, .init())
+	}
+
+	func test_DateNumberAttribute_Sampleable() {
+		// TEST:
+		// Encoder is set to use
+		// seconds since 1970 as
+		// date format
+
+		let encoder = JSONEncoder()
+		encoder.outputFormatting = .prettyPrinted
+		encoder.dateEncodingStrategy = .secondsSince1970
+
+		let node = try! Attribute<Date>.genericOpenAPINode(using: encoder)
+
+		XCTAssertTrue(node.required)
+		XCTAssertEqual(node.jsonTypeFormat, .number(.double))
+
+		guard case .number(let contextA, let numberContext) = node else {
+			XCTFail("Expected string Node")
+			return
+		}
+
+		XCTAssertEqual(contextA, .init(format: .double,
+									   required: true,
+									   nullable: false,
+									   allowedValues: nil))
+
+		XCTAssertEqual(numberContext, .init())
+	}
+
+	func test_DateDeferredAttribute() {
+		// TEST:
+		// Encoder is set to use
+		// Date default encoding
+
+		let encoder = JSONEncoder()
+		encoder.outputFormatting = .prettyPrinted
+		encoder.dateEncodingStrategy = .deferredToDate
+
+		let node = Attribute<Date>.dateOpenAPINodeGuess(using: encoder)
+
+		XCTAssertNil(node)
+	}
+
+	func test_DateDeferredAttribute_Sampleable() {
+		// TEST:
+		// Encoder is set to use
+		// Date default encoding
+
+		let encoder = JSONEncoder()
+		encoder.outputFormatting = .prettyPrinted
+		encoder.dateEncodingStrategy = .deferredToDate
+
 		let node = try! Attribute<Date>.genericOpenAPINode(using: encoder)
 
 		XCTAssertTrue(node.required)
@@ -631,7 +868,7 @@ extension JSONAPIAttributeOpenAPITests {
 	}
 }
 
-extension Date: Sampleable {
+extension Date: SampleableOpenAPIType {
 	public static var sample: Date {
 		return TimeInterval.arbitrary.map { Date(timeIntervalSince1970: $0) }.generate
 	}

Tests/JSONAPIOpenAPITests/JSONAPIEntityOpenAPITests.swift

@@ -40,7 +40,16 @@ class JSONAPIEntityOpenAPITests: XCTestCase {
 	}
 
 	func test_AttributesEntity() {
-		let node = try! TestType2.openAPINode(using: JSONEncoder())
+
+		let dateFormatter = DateFormatter()
+		dateFormatter.dateStyle = .medium
+		dateFormatter.timeStyle = .short
+		dateFormatter.locale = Locale(identifier: "en_US")
+
+		let encoder = JSONEncoder()
+		encoder.dateEncodingStrategy = .formatted(dateFormatter)
+
+		let node = try! TestType2.openAPINode(using: encoder)
 
 		XCTAssertTrue(node.required)
 		XCTAssertEqual(node.jsonTypeFormat, .object(.generic))
@@ -83,9 +92,9 @@ class JSONAPIEntityOpenAPITests: XCTestCase {
 									   nullable: false,
 									   allowedValues: nil))
 
-		XCTAssertEqual(attributesContext.minProperties, 3)
-		XCTAssertEqual(Set(attributesContext.requiredProperties), Set(["stringProperty", "enumProperty", "nullableProperty"]))
-		XCTAssertEqual(Set(attributesContext.properties.keys), Set(["stringProperty", "enumProperty", "optionalProperty", "nullableProperty", "nullableOptionalProperty"]))
+		XCTAssertEqual(attributesContext.minProperties, 4)
+		XCTAssertEqual(Set(attributesContext.requiredProperties), Set(["stringProperty", "enumProperty", "dateProperty", "nullableProperty"]))
+		XCTAssertEqual(Set(attributesContext.properties.keys), Set(["stringProperty", "enumProperty", "dateProperty", "optionalProperty", "nullableProperty", "nullableOptionalProperty"]))
 
 		XCTAssertEqual(attributesContext.properties["stringProperty"],
 					   .string(.init(format: .generic,
@@ -99,6 +108,13 @@ class JSONAPIEntityOpenAPITests: XCTestCase {
 									 allowedValues: ["one", "two"].map(AnyCodable.init)),
 							   .init()))
 
+		XCTAssertEqual(attributesContext.properties["dateProperty"],
+					   .string(.init(format: .dateTime,
+									 required: true,
+									 nullable: false,
+									 allowedValues: nil),
+							   .init()))
+
 		XCTAssertEqual(attributesContext.properties["optionalProperty"],
 					   .string(.init(format: .generic,
 									 required: false,
@@ -268,6 +284,7 @@ extension JSONAPIEntityOpenAPITests {
 		public struct Attributes: JSONAPI.Attributes, Sampleable {
 			let stringProperty: Attribute<String>
 			let enumProperty: Attribute<EnumType>
+			let dateProperty: Attribute<Date>
 			let optionalProperty: Attribute<String>?
 			let nullableProperty: Attribute<String?>
 			let nullableOptionalProperty: Attribute<String?>?
@@ -278,6 +295,7 @@ extension JSONAPIEntityOpenAPITests {
 			public static var sample: Attributes {
 				return Attributes(stringProperty: .init(value: "hello"),
 								  enumProperty: .init(value: .one),
+								  dateProperty: .init(value: Date()),
 								  optionalProperty: nil,
 								  nullableProperty: .init(value: nil),
 								  nullableOptionalProperty: nil)

Tests/JSONAPIOpenAPITests/OpenAPI/OpenAPITests.swift

@@ -0,0 +1,52 @@
+//
+//  OpenAPITests.swift
+//  JSONAPIOpenAPITests
+//
+//  Created by Mathew Polzin on 1/25/19.
+//
+
+import XCTest
+import JSONAPI
+import JSONAPIOpenAPI
+
+class OpenAPITests: XCTestCase {
+
+	func test_placeholder() {
+
+		let schemaInfo = OpenAPISchema.Info(title: "Cool API", version: "0.1.0")
+
+		let personResponse = OpenAPIResponse(description: "Successfully created a Person",
+											 content: [
+												.json: .init(schema: .init(JSONReference.node(.init(type: \.schemas, selector: "person"))))
+			])
+
+		let schemaPaths: [OpenAPISchema.PathComponents: OpenAPIPathItem] = [
+			.init(["api","people"]):
+			.operations(
+				.init(parameters: [],
+					  post: OpenAPIPathItem.PathProperties.Operation(
+						summary: "",
+						operationId: "createPerson",
+						parameters: [],
+						responses: [
+							.status(code: 200): .init(personResponse)
+						]
+					)
+				)
+			)
+		]
+
+		let schemaComponents = OpenAPIComponents(schemas: ["person": .reference(.file("person.json"))],
+												 parameters: [:])
+
+		let openAPISchema = OpenAPISchema(info: schemaInfo,
+										  paths: schemaPaths,
+										  components: schemaComponents)
+
+		let encoder = JSONEncoder()
+		encoder.outputFormatting = .prettyPrinted
+
+		print(String(data: try! encoder.encode(openAPISchema), encoding: .utf8)!)
+	}
+
+}