Xcode 10.1, Swift 4.1, install [Mockingjay](https://github.com/kylef/Mockingjay) with Cocoapods

XCTestCase+Stub.swift

//  XCTestCase+Stub.swift

import Foundation
import XCTest
import Mockingjay

extension XCTestCase {
    /// Web API のリクエストをテストプロジェクトの json でスタブする
    ///
    /// - Parameters:
    ///   - uriStr: URI
    ///   - status: ステータスコード
    ///   - with: 拡張子なしのファイル名
    func stub(uri uriStr: String, status: Int = 200, with resource: String) {
        let testBundle = Bundle(for: type(of: self))
        let path = testBundle.url(forResource: resource, withExtension: "json")
        let data: NSData? = try? NSData(contentsOf: path!, options: .uncached)
        self.stub(uri(uriStr), jsonData(data! as Data, status: status))
    }
}