diff --git a/JSONAPI.playground/Pages/Test Library.xcplaygroundpage/Contents.swift b/JSONAPI.playground/Pages/Test Library.xcplaygroundpage/Contents.swift
new file mode 100644
index 0000000..3c67cca
--- /dev/null
+++ b/JSONAPI.playground/Pages/Test Library.xcplaygroundpage/Contents.swift	
@@ -0,0 +1,16 @@
+//: [Previous](@previous)
+
+import Foundation
+import JSONAPI
+import JSONAPITestLib
+
+/*******
+
+Please enjoy these examples, but allow me the forced casting and the lack of error checking for the sake of brevity.
+
+********/
+
+// MARK: - Literal Expressibility
+// The JSONAPITestLib provides literal expressibility for key types to
+// make creating tests easier
+let dog = Dog(id: "1234", attributes: Dog.Attributes(name: "Buddy"), relationships: Dog.Relationships(owner: nil))
diff --git a/JSONAPI.playground/Contents.swift b/JSONAPI.playground/Pages/Usage.xcplaygroundpage/Contents.swift
similarity index 100%
rename from JSONAPI.playground/Contents.swift
rename to JSONAPI.playground/Pages/Usage.xcplaygroundpage/Contents.swift
diff --git a/JSONAPI.playground/Sources/Entities.swift b/JSONAPI.playground/Sources/Entities.swift
index e466b35..2ad13b2 100644
--- a/JSONAPI.playground/Sources/Entities.swift
+++ b/JSONAPI.playground/Sources/Entities.swift
@@ -34,12 +34,23 @@ public enum PersonDescription: EntityDescription {
 	public struct Attributes: JSONAPI.Attributes {
 		public let name: Attribute<[String]>
 		public let favoriteColor: Attribute<String>
+
+		public init(name: Attribute<[String]>, favoriteColor: Attribute<String>) {
+			self.name = name
+			self.favoriteColor = favoriteColor
+		}
 	}
 	
 	public struct Relationships: JSONAPI.Relationships {
 		public let friends: ToManyRelationship<Person>
 		public let dogs: ToManyRelationship<Dog>
 		public let home: ToOneRelationship<House>
+
+		public init(friends: ToManyRelationship<Person>, dogs: ToManyRelationship<Dog>, home: ToOneRelationship<House>) {
+			self.friends = friends
+			self.dogs = dogs
+			self.home = home
+		}
 	}
 }
 
@@ -57,10 +68,18 @@ public enum DogDescription: EntityDescription {
 
 	public struct Attributes: JSONAPI.Attributes {
 		public let name: Attribute<String>
+
+		public init(name: Attribute<String>) {
+			self.name = name
+		}
 	}
 
 	public struct Relationships: JSONAPI.Relationships {
 		public let owner: ToOneRelationship<Person?>
+
+		public init(owner: ToOneRelationship<Person?>) {
+			self.owner = owner
+		}
 	}
 }
 
diff --git a/JSONAPI.playground/contents.xcplayground b/JSONAPI.playground/contents.xcplayground
index a93d484..8df8fa3 100644
--- a/JSONAPI.playground/contents.xcplayground
+++ b/JSONAPI.playground/contents.xcplayground
@@ -1,4 +1,7 @@
 <?xml version="1.0" encoding="UTF-8" standalone="yes"?>
-<playground version='5.0' target-platform='macos' executeOnSourceChanges='false'>
-    <timeline fileName='timeline.xctimeline'/>
+<playground version='6.0' target-platform='macos' executeOnSourceChanges='false'>
+    <pages>
+        <page name='Test Library'/>
+        <page name='Usage'/>
+    </pages>
 </playground>
\ No newline at end of file
diff --git a/Sources/JSONAPI/Resource/Relationship.swift b/Sources/JSONAPI/Resource/Relationship.swift
index 27e7d1b..23d1958 100644
--- a/Sources/JSONAPI/Resource/Relationship.swift
+++ b/Sources/JSONAPI/Resource/Relationship.swift
@@ -12,10 +12,6 @@
 public struct ToOneRelationship<Relatable: JSONAPI.OptionalRelatable>: Equatable, Codable {
 
 	public let id: Relatable.WrappedIdentifier
-	
-	public var ids: [Relatable.WrappedIdentifier] {
-		return [id]
-	}
 
 	public init(id: Relatable.WrappedIdentifier) {
 		self.id = id
diff --git a/Sources/JSONAPITestLib/Relationship+Literal.swift b/Sources/JSONAPITestLib/Relationship+Literal.swift
new file mode 100644
index 0000000..ce22903
--- /dev/null
+++ b/Sources/JSONAPITestLib/Relationship+Literal.swift
@@ -0,0 +1,14 @@
+//
+//  Relationship+Literal.swift
+//  JSONAPITestLib
+//
+//  Created by Mathew Polzin on 11/27/18.
+//
+
+import JSONAPI
+
+extension ToOneRelationship: ExpressibleByNilLiteral where Relatable.WrappedIdentifier: ExpressibleByNilLiteral {
+	public init(nilLiteral: ()) {
+		self.init(id: Relatable.WrappedIdentifier(nilLiteral: ()))
+	}
+}
diff --git a/Tests/JSONAPITests/Entity/EntityTests.swift b/Tests/JSONAPITests/Entity/EntityTests.swift
index d69ae03..236d558 100644
--- a/Tests/JSONAPITests/Entity/EntityTests.swift
+++ b/Tests/JSONAPITests/Entity/EntityTests.swift
@@ -37,7 +37,7 @@ class EntityTests: XCTestCase {
 		let entity1 = TestEntity1()
 		let entity2 = TestEntity2(other: entity1.pointer)
 		
-		XCTAssertEqual(entity2.relationships.other.ids, [entity1.id])
+		XCTAssertEqual(entity2.relationships.other.id, entity1.id)
 	}
 }
 
diff --git a/Tests/JSONAPITests/Relationships/RelationshipTests.swift b/Tests/JSONAPITests/Relationships/RelationshipTests.swift
index 3c36d3a..35fe44d 100644
--- a/Tests/JSONAPITests/Relationships/RelationshipTests.swift
+++ b/Tests/JSONAPITests/Relationships/RelationshipTests.swift
@@ -40,7 +40,6 @@ extension RelationshipTests {
 								   data: to_one_relationship)
 
 		XCTAssertEqual(relationship.id.rawValue, "2DF03B69-4B0A-467F-B52E-B0C9E44FCECF")
-		XCTAssertEqual(relationship.ids.count, 1)
 	}
 
 	func test_ToOneRelationship_encode() {
diff --git a/Tests/JSONAPITests/TestLib/Relationship+LiteralTests.swift b/Tests/JSONAPITests/TestLib/Relationship+LiteralTests.swift
new file mode 100644
index 0000000..2558328
--- /dev/null
+++ b/Tests/JSONAPITests/TestLib/Relationship+LiteralTests.swift
@@ -0,0 +1,29 @@
+//
+//  Relationship+LiteralTests.swift
+//  JSONAPITests
+//
+//  Created by Mathew Polzin on 11/27/18.
+//
+
+import XCTest
+import JSONAPI
+import JSONAPITestLib
+
+class Relationship_LiteralTests: XCTestCase {
+
+	func test_NilLiteral() {
+		XCTAssertEqual(ToOneRelationship<TestEntity?>(id: nil), nil)
+	}
+}
+
+// MARK: - Test types
+extension Relationship_LiteralTests {
+	enum TestDescription: EntityDescription {
+		public static var type: String { return "test" }
+
+		public typealias Attributes = NoAttributes
+		public typealias Relationships = NoRelationships
+	}
+
+	typealias TestEntity = Entity<TestDescription>
+}