Make package available, albeit with crippled testing, without OS X 10.13 and its convenient additions to JSONEncoder/Decoder

Author: mattpolzin

Package.swift

@@ -6,7 +6,7 @@ import PackageDescription
 let package = Package(
     name: "OpenAPIKit",
     platforms: [
-        .macOS(.v10_13),
+        .macOS(.v10_10),
         .iOS(.v11)
     ],
     products: [

Tests/OpenAPIKitTests/ContentTests.swift

@@ -26,7 +26,7 @@ final class ContentTests: XCTestCase {
 }
 
 // MARK: - Codable
-
+@available(OSX 10.13, *)
 extension ContentTests {
     func test_referenceContent_encode() {
         let content = OpenAPI.Content(schema: .init(.file("hello.json#/world")))

Tests/OpenAPIKitTests/RequestTests.swift

@@ -43,7 +43,7 @@ final class RequestTests: XCTestCase {
 }
 
 // MARK: - Codable
-
+@available(OSX 10.13, *)
 extension RequestTests {
     func test_onlyEmptyContent_encode() {
         let content: OpenAPI.Content.Map = [:]
@@ -216,7 +216,7 @@ extension RequestTests {
 }
 
 // MARK: Other Content Types
-
+@available(OSX 10.13, *)
 extension RequestTests {
     func test_xml_onlySchemaContent_encode() {
         let schema = JSONSchema.object(

Tests/OpenAPIKitTests/Schema Object/SchemaObjectTests.swift

@@ -341,12 +341,14 @@ final class SchemaObjectTests: XCTestCase {
         XCTAssertNil(reference.allowedValues)
     }
 
+    @available(OSX 10.13, *)
     func test_withInitialExample() {
         let object = JSONSchema.object(.init(format: .unspecified, required: true, example: (codable: [:], encoder: testEncoder)), .init(properties: [:]))
 
         XCTAssertEqual(object.example, "{\n\n}")
     }
 
+    @available(OSX 10.13, *)
     func test_withAddedExample() {
         let object = try! JSONSchema.object(.init(format: .unspecified, required: true), .init(properties: [:]))
             .with(example: [String: String](), using: testEncoder)
@@ -418,7 +420,7 @@ final class SchemaObjectTests: XCTestCase {
 }
 
 // MARK: - Codable
-
+@available(OSX 10.13, *)
 extension SchemaObjectTests {
 
     func test_decodeingFailsForTypo() {
@@ -3000,6 +3002,7 @@ extension SchemaObjectTests {
     }
 }
 
+@available(OSX 10.13, *)
 private func testEncodingPropertyLines<T: Encodable>(entity: T, propertyLines: [String]) {
     var expectedString = "{\n"
     for line in propertyLines {
@@ -3010,6 +3013,7 @@ private func testEncodingPropertyLines<T: Encodable>(entity: T, propertyLines: [
     XCTAssertEqual(try? testStringFromEncoding(of: entity), expectedString)
 }
 
+@available(OSX 10.13, *)
 private func testAllSharedSimpleContextEncoding<T: Encodable>(
     typeName: String,
     requiredEntity: T,
@@ -3039,6 +3043,7 @@ private func testAllSharedSimpleContextEncoding<T: Encodable>(
     ])
 }
 
+@available(OSX 10.13, *)
 private func testAllSharedFormattedContextEncoding<T: Encodable>(
     typeName: String,
     formatName: String,

Tests/OpenAPIKitTests/TestHelpers.swift

@@ -7,6 +7,7 @@
 
 import Foundation
 
+@available(OSX 10.13, *)
 let testEncoder = { () -> JSONEncoder in
     let encoder = JSONEncoder()
     encoder.dateEncodingStrategy = .iso8601
@@ -15,10 +16,12 @@ let testEncoder = { () -> JSONEncoder in
     return encoder
 }()
 
+@available(OSX 10.13, *)
 func testStringFromEncoding<T: Encodable>(of entity: T) throws -> String? {
     return String(data: try testEncoder.encode(entity), encoding: .utf8)
 }
 
+@available(OSX 10.12, *)
 let testDecoder = { () -> JSONDecoder in
     let decoder = JSONDecoder()
     decoder.dateDecodingStrategy = .iso8601