test some attribute encoding a bit further

Sources/JSONAPI/Resource/Attribute.swift

@@ -11,7 +11,7 @@ public protocol AttributeType: Codable {
 // MARK: TransformedAttribute
 /// A TransformedAttribute takes a Codable type and attempts to turn it into another type.
 public struct TransformedAttribute<RawValue: Codable, Transformer: JSONAPI.Transformer>: AttributeType where Transformer.From == RawValue {
-	private let rawValue: RawValue
+	let rawValue: RawValue
 	
 	public let value: Transformer.To
 	

Tests/JSONAPITests/Attribute/AttributeTests.swift

@@ -30,6 +30,18 @@ class AttributeTests: XCTestCase {
 		XCTAssertNoThrow(try TransformedAttribute<String, TestTransformer>(transformedValue: 10))
 	}
 
+	func test_EncodedPrimitives() {
+		testEncodedPrimitive(attribute: Attribute<Int>(value: 10))
+		testEncodedPrimitive(attribute: Attribute<Bool>(value: false))
+		testEncodedPrimitive(attribute: Attribute<Double>(value: 10.2))
+
+		testEncodedPrimitive(attribute: try! TransformedAttribute<Int, IntToString>(rawValue: 10))
+		testEncodedPrimitive(attribute: try! TransformedAttribute<Int, IntToInt>(rawValue: 10))
+		testEncodedPrimitive(attribute: try! TransformedAttribute<Int, IntToDouble>(rawValue: 10))
+		testEncodedPrimitive(attribute: try! TransformedAttribute<String, TestTransformer>(rawValue: "10"))
+		testEncodedPrimitive(attribute: try! TransformedAttribute<String?, OptionalToString<String>>(rawValue: "10"))
+	}
+
 	func test_NullableIsNullIfNil() {
 		struct Wrapper: Codable {
 			let dummy: Attribute<String?>
@@ -68,4 +80,28 @@ extension AttributeTests {
 			return String(value)
 		}
 	}
+
+	enum IntToString: Transformer {
+		public static func transform(_ from: Int) -> String {
+			return String(from)
+		}
+	}
+
+	enum IntToInt: Transformer {
+		public static func transform(_ from: Int) -> Int {
+			return from + 100
+		}
+	}
+
+	enum IntToDouble: Transformer {
+		public static func transform(_ from: Int) -> Double {
+			return Double(from)
+		}
+	}
+
+	enum OptionalToString<T>: Transformer {
+		public static func transform(_ from: T?) -> String {
+			return String(describing: from)
+		}
+	}
 }

Tests/JSONAPITests/Test Helpers/EncodedAttributeTest.swift

@@ -0,0 +1,34 @@
+//
+//  EncodedAttributeTest.swift
+//  JSONAPITests
+//
+//  Created by Mathew Polzin on 12/21/18.
+//
+
+import Foundation
+import XCTest
+@testable import JSONAPI
+import JSONAPITestLib
+
+private struct Wrapper<Value: Equatable & Codable, Transform: Transformer>: Codable where Value == Transform.From {
+	let x: TransformedAttribute<Value, Transform>
+
+	init(x: TransformedAttribute<Value, Transform>) {
+		self.x = x
+	}
+}
+
+/// This function attempts to just cast to the type, so it only works
+/// for Attributes of primitive types.
+func testEncodedPrimitive<Value: Equatable & Codable, Transform: Transformer>(attribute: TransformedAttribute<Value, Transform>) {
+	let encodedAttributeData = encoded(value: Wrapper<Value, Transform>(x: attribute))
+	let wrapperObject = try! JSONSerialization.jsonObject(with: encodedAttributeData, options: []) as! [String: Any]
+	let jsonObject = wrapperObject["x"]
+
+	guard let jsonAttribute = jsonObject as? Transform.From else {
+		XCTFail("Attribute did not encode to the correct type")
+		return
+	}
+
+	XCTAssertEqual(attribute.rawValue, jsonAttribute)
+}

Tests/JSONAPITests/Test Helpers/EncodedEntityPropertyTest.swift

@@ -49,20 +49,3 @@ func testEncoded<E: EntityType>(entity: E) {
 		XCTAssertNotNil(jsonLinks)
 	}
 }
-
-// MARK: - Extensions to help with identifying structure of Mirror
-private protocol OptionalAttributeType {}
-extension Optional: OptionalAttributeType where Wrapped: AttributeType {}
-
-private protocol OptionalArray {}
-extension Optional: OptionalArray where Wrapped: ArrayType {}
-
-private protocol AttributeTypeWithOptionalArray {}
-extension TransformedAttribute: AttributeTypeWithOptionalArray where RawValue: OptionalArray {}
-
-private protocol OptionalRelationshipType {}
-extension Optional: OptionalRelationshipType where Wrapped: RelationshipType {}
-
-private protocol _RelationshipType {}
-extension ToOneRelationship: _RelationshipType {}
-extension ToManyRelationship: _RelationshipType {}