Add tests to confirm that Entities can safely have computed attributes or relationships.

README.md

@@ -100,6 +100,7 @@ To create an Xcode project for JSONAPI, run
 - [x] Roll my own `Result` or find an alternative that doesn't use `Foundation`.
 - [ ] Create more descriptive errors that are easier to use for troubleshooting.
 - [x] Make it easier to construct `Attributes` and `Relationships` values in test cases (literal expressibility).
+- [ ] Make `TransformedAttribute` a Monad (or at least a Functor).
 
 ## Usage
 

Tests/JSONAPITests/Computed Properties/ComputedPropertiesTests.swift

@@ -0,0 +1,61 @@
+//
+//  ComputedPropertiesTests.swift
+//  JSONAPITests
+//
+//  Created by Mathew Polzin on 11/28/18.
+//
+
+import XCTest
+import JSONAPI
+import JSONAPITestLib
+
+class ComputedPropertiesTests: XCTestCase {
+	func test_DecodeIgnoresComputed() {
+		let entity = decoded(type: TestType.self, data: computed_property_attribute)
+
+		XCTAssertEqual(entity.id, "1234")
+		XCTAssertEqual(entity[\.name], "Sarah")
+		XCTAssertEqual(entity ~> \.other, "5678")
+		XCTAssertNoThrow(try TestType.check(entity))
+	}
+
+	func test_EncodeIgnoresComputed() {
+		test_DecodeEncodeEquality(type: TestType.self, data: computed_property_attribute)
+	}
+
+	func test_ComputedAttributeAccess() {
+		let entity = decoded(type: TestType.self, data: computed_property_attribute)
+
+		XCTAssertEqual(entity[\.computed], "Sarah")
+	}
+
+	func test_ComputedRelationshipAccess() {
+		let entity = decoded(type: TestType.self, data: computed_property_attribute)
+
+		XCTAssertEqual(entity ~> \.computed, "5678")
+	}
+}
+
+// MARK: Test types
+extension ComputedPropertiesTests {
+	public enum TestTypeDescription: EntityDescription {
+		public static var type: String { return "test" }
+
+		public struct Attributes: JSONAPI.Attributes {
+			public let name: Attribute<String>
+			public var computed: Attribute<String> {
+				return name
+			}
+		}
+
+		public struct Relationships: JSONAPI.Relationships {
+			public let other: ToOneRelationship<TestType>
+
+			public var computed: ToOneRelationship<TestType> {
+				return other
+			}
+		}
+	}
+
+	public typealias TestType = Entity<TestTypeDescription>
+}

Tests/JSONAPITests/Computed Properties/stubs/ComputedPropertiesStubs.swift

@@ -0,0 +1,24 @@
+//
+//  ComputedPropertiesStubs.swift
+//  JSONAPITests
+//
+//  Created by Mathew Polzin on 11/28/18.
+//
+
+let computed_property_attribute = """
+{
+	"id": "1234",
+	"type": "test",
+	"attributes": {
+		"name": "Sarah"
+	},
+	"relationships": {
+		"other": {
+			"data": {
+				"id": "5678",
+				"type": "test"
+			}
+		}
+	}
+}
+""".data(using: .utf8)!