diff --git a/Tests/JSONAPITests/Entity/EntityTests.swift b/Tests/JSONAPITests/Entity/EntityTests.swift
index 01d37b7..e08111d 100644
--- a/Tests/JSONAPITests/Entity/EntityTests.swift
+++ b/Tests/JSONAPITests/Entity/EntityTests.swift
@@ -45,12 +45,15 @@ class EntityTests: XCTestCase {
 		let entity1 = TestEntity1(id: .init(rawValue: "wow"))
 		let entity2 = TestEntity2(id: .init(rawValue: "cool"), relationships: .init(other: .init(entity: entity1)))
 		let _ = TestEntity3(id: .init(rawValue: "3"), relationships: .init(others: .init(ids: [.init(rawValue: "10"), .init(rawValue: "20"), entity1.id])))
+		let _ = TestEntity3(id: .init(rawValue: "3"), relationships: .init(others: .none))
 		let _ = TestEntity4(id: .init(rawValue: "4"), attributes: .init(word: .init(value: "hello"), number: .init(value: 10), array: .init(value: [10.2, 10.3])), relationships: .init(other: entity2.pointer))
 		let _ = TestEntity5(id: .init(rawValue: "5"), attributes: .init(floater: .init(value: 10.2)))
 		let _ = TestEntity6(id: .init(rawValue: "6"), attributes: .init(here: .init(value: "here"), maybeHere: nil, maybeNull: .init(value: nil)))
 		let _ = TestEntity7(id: .init(rawValue: "7"), attributes: .init(here: .init(value: "hello"), maybeHereMaybeNull: .init(value: "world")))
 		XCTAssertNoThrow(try TestEntity8(id: .init(rawValue: "8"), attributes: .init(string: .init(value: "hello"), int: .init(value: 10), stringFromInt: .init(rawValue: 20), plus: .init(rawValue: 30), doubleFromInt: .init(rawValue: 32), omitted: nil, nullToString: .init(rawValue: nil))))
 		let _ = TestEntity9(id: .init(rawValue: "9"), relationships: .init(one: entity1.pointer, nullableOne: nil))
+		let _ = TestEntity9(id: .init(rawValue: "9"), relationships: .init(one: entity1.pointer, nullableOne: .init(entity: nil)))
+		let _ = TestEntity9(id: .init(rawValue: "9"), relationships: .init(one: entity1.pointer, nullableOne: .init(entity: entity1, meta: .none, links: .none)))
 		let e10id1 = TestEntity10.Identifier(rawValue: "hello")
 		let e10id2 = TestEntity10.Id(rawValue: "world")
 		let e10id3: TestEntity10.Id = "!"
diff --git a/Tests/JSONAPITests/Relationships/RelationshipTests.swift b/Tests/JSONAPITests/Relationships/RelationshipTests.swift
index 1216f0c..6d3f176 100644
--- a/Tests/JSONAPITests/Relationships/RelationshipTests.swift
+++ b/Tests/JSONAPITests/Relationships/RelationshipTests.swift
@@ -47,6 +47,46 @@ extension RelationshipTests {
 								   data: to_one_relationship)
 	}
 
+	func test_ToOneRelationshipWithMeta() {
+		let relationship = decoded(type: ToOneWithMeta.self,
+								   data: to_one_relationship_with_meta)
+
+		XCTAssertEqual(relationship.id.rawValue, "2DF03B69-4B0A-467F-B52E-B0C9E44FCECF")
+		XCTAssertEqual(relationship.meta.a, "hello")
+	}
+
+	func test_ToOneRelationshipWithMeta_encode() {
+		test_DecodeEncodeEquality(type: ToOneWithMeta.self,
+								  data: to_one_relationship_with_meta)
+	}
+
+	func test_ToOneRelationshipWithLinks() {
+		let relationship = decoded(type: ToOneWithLinks.self,
+								   data: to_one_relationship_with_links)
+
+		XCTAssertEqual(relationship.id.rawValue, "2DF03B69-4B0A-467F-B52E-B0C9E44FCECF")
+		XCTAssertEqual(relationship.links.b, .init(url: "world"))
+	}
+
+	func test_ToOneRelationshipWithLinks_encode() {
+		test_DecodeEncodeEquality(type: ToOneWithLinks.self,
+								  data: to_one_relationship_with_links)
+	}
+
+	func test_ToOneRelationshipWithMetaAndLinks() {
+		let relationship = decoded(type: ToOneWithMetaAndLinks.self,
+								   data: to_one_relationship_with_meta_and_links)
+
+		XCTAssertEqual(relationship.id.rawValue, "2DF03B69-4B0A-467F-B52E-B0C9E44FCECF")
+		XCTAssertEqual(relationship.meta.a, "hello")
+		XCTAssertEqual(relationship.links.b, .init(url: "world"))
+	}
+
+	func test_ToOneRelationshipWithMetaAndLinks_encode() {
+		test_DecodeEncodeEquality(type: ToOneWithMetaAndLinks.self,
+								  data: to_one_relationship_with_meta_and_links)
+	}
+
 	func test_ToManyRelationship() {
 		let relationship = decoded(type: ToManyRelationship<TestEntity1, NoMetadata, NoLinks>.self,
 								   data: to_many_relationship)
@@ -58,6 +98,46 @@ extension RelationshipTests {
 		test_DecodeEncodeEquality(type: ToManyRelationship<TestEntity1, NoMetadata, NoLinks>.self,
 								   data: to_many_relationship)
 	}
+
+	func test_ToManyRelationshipWithMeta() {
+		let relationship = decoded(type: ToManyWithMeta.self,
+								   data: to_many_relationship_with_meta)
+
+		XCTAssertEqual(relationship.ids.map { $0.rawValue }, ["2DF03B69-4B0A-467F-B52E-B0C9E44FCECF", "90F03B69-4DF1-467F-B52E-B0C9E44FC333", "2DF03B69-4B0A-467F-B52E-B0C9E44FCECF"])
+		XCTAssertEqual(relationship.meta.a, "hello")
+	}
+
+	func test_ToManyRelationshipWithMeta_encode() {
+		test_DecodeEncodeEquality(type: ToManyWithMeta.self,
+								  data: to_many_relationship_with_meta)
+	}
+
+	func test_ToManyRelationshipWithLinks() {
+		let relationship = decoded(type: ToManyWithLinks.self,
+								   data: to_many_relationship_with_links)
+
+		XCTAssertEqual(relationship.ids.map { $0.rawValue }, ["2DF03B69-4B0A-467F-B52E-B0C9E44FCECF", "90F03B69-4DF1-467F-B52E-B0C9E44FC333", "2DF03B69-4B0A-467F-B52E-B0C9E44FCECF"])
+		XCTAssertEqual(relationship.links.b, .init(url: "world"))
+	}
+
+	func test_ToManyRelationshipWithLinks_encode() {
+		test_DecodeEncodeEquality(type: ToManyWithLinks.self,
+								  data: to_many_relationship_with_links)
+	}
+
+	func test_ToManyRelationshipWithMetaAndLinks() {
+		let relationship = decoded(type: ToManyWithMetaAndLinks.self,
+								   data: to_many_relationship_with_meta_and_links)
+
+		XCTAssertEqual(relationship.ids.map { $0.rawValue }, ["2DF03B69-4B0A-467F-B52E-B0C9E44FCECF", "90F03B69-4DF1-467F-B52E-B0C9E44FC333", "2DF03B69-4B0A-467F-B52E-B0C9E44FCECF"])
+		XCTAssertEqual(relationship.meta.a, "hello")
+		XCTAssertEqual(relationship.links.b, .init(url: "world"))
+	}
+
+	func test_ToManyRelationshipWithMetaAndLinks_encode() {
+		test_DecodeEncodeEquality(type: ToManyWithMetaAndLinks.self,
+								  data: to_many_relationship_with_meta_and_links)
+	}
 }
 
 // MARK: Failure tests
@@ -82,4 +162,23 @@ extension RelationshipTests {
 	}
 
 	typealias TestEntity1 = BasicEntity<TestEntityType1>
+
+	typealias ToOneWithMeta = ToOneRelationship<TestEntity1, TestMeta, NoLinks>
+
+	typealias ToOneWithLinks = ToOneRelationship<TestEntity1, NoMetadata, TestLinks>
+	typealias ToOneWithMetaAndLinks = ToOneRelationship<TestEntity1, TestMeta, TestLinks>
+
+	typealias ToManyWithMeta = ToManyRelationship<TestEntity1, TestMeta, NoLinks>
+	typealias ToManyWithLinks = ToManyRelationship<TestEntity1, NoMetadata, TestLinks>
+	typealias ToManyWithMetaAndLinks = ToManyRelationship<TestEntity1, TestMeta, TestLinks>
+
+	struct TestMeta: JSONAPI.Meta {
+		let a: String
+	}
+
+	typealias TestLink = JSONAPI.Link<String, NoMetadata>
+
+	struct TestLinks: JSONAPI.Links {
+		let b: TestLink
+	}
 }
diff --git a/Tests/JSONAPITests/Relationships/stubs/RelationshipStubs.swift b/Tests/JSONAPITests/Relationships/stubs/RelationshipStubs.swift
index 6be0d90..2f5d6d5 100644
--- a/Tests/JSONAPITests/Relationships/stubs/RelationshipStubs.swift
+++ b/Tests/JSONAPITests/Relationships/stubs/RelationshipStubs.swift
@@ -23,6 +23,45 @@ let to_one_relationship_type_mismatch = """
 }
 """.data(using: .utf8)!
 
+let to_one_relationship_with_meta = """
+{
+	"data": {
+		"type": "test_entity1",
+		"id": "2DF03B69-4B0A-467F-B52E-B0C9E44FCECF"
+	},
+	"meta": {
+		"a": "hello"
+	}
+}
+""".data(using: .utf8)!
+
+let to_one_relationship_with_links = """
+{
+	"data": {
+		"type": "test_entity1",
+		"id": "2DF03B69-4B0A-467F-B52E-B0C9E44FCECF"
+	},
+	"links": {
+		"b": "world"
+	}
+}
+""".data(using: .utf8)!
+
+let to_one_relationship_with_meta_and_links = """
+{
+	"data": {
+		"type": "test_entity1",
+		"id": "2DF03B69-4B0A-467F-B52E-B0C9E44FCECF"
+	},
+	"meta": {
+		"a": "hello"
+	},
+	"links": {
+		"b": "world"
+	}
+}
+""".data(using: .utf8)!
+
 let to_many_relationship = """
 {
 	"data": [
@@ -42,6 +81,75 @@ let to_many_relationship = """
 }
 """.data(using: .utf8)!
 
+let to_many_relationship_with_meta = """
+{
+	"data": [
+		{
+			"type": "test_entity1",
+			"id": "2DF03B69-4B0A-467F-B52E-B0C9E44FCECF"
+		},
+		{
+			"type": "test_entity1",
+			"id": "90F03B69-4DF1-467F-B52E-B0C9E44FC333"
+		},
+		{
+			"type": "test_entity1",
+			"id": "2DF03B69-4B0A-467F-B52E-B0C9E44FCECF"
+		}
+	],
+	"meta": {
+		"a": "hello"
+	}
+}
+""".data(using: .utf8)!
+
+let to_many_relationship_with_links = """
+{
+	"data": [
+		{
+			"type": "test_entity1",
+			"id": "2DF03B69-4B0A-467F-B52E-B0C9E44FCECF"
+		},
+		{
+			"type": "test_entity1",
+			"id": "90F03B69-4DF1-467F-B52E-B0C9E44FC333"
+		},
+		{
+			"type": "test_entity1",
+			"id": "2DF03B69-4B0A-467F-B52E-B0C9E44FCECF"
+		}
+	],
+	"links": {
+		"b": "world"
+	}
+}
+""".data(using: .utf8)!
+
+let to_many_relationship_with_meta_and_links = """
+{
+	"data": [
+		{
+			"type": "test_entity1",
+			"id": "2DF03B69-4B0A-467F-B52E-B0C9E44FCECF"
+		},
+		{
+			"type": "test_entity1",
+			"id": "90F03B69-4DF1-467F-B52E-B0C9E44FC333"
+		},
+		{
+			"type": "test_entity1",
+			"id": "2DF03B69-4B0A-467F-B52E-B0C9E44FCECF"
+		}
+	],
+	"meta": {
+		"a": "hello"
+	},
+	"links": {
+		"b": "world"
+	}
+}
+""".data(using: .utf8)!
+
 let to_many_relationship_type_mismatch = """
 {
 	"data": [