Replacer

Replacer is an easy-to-use library to stub HTTP requests and to swizzle methods.

Specifically, URLSession’s response can be replaced with any JSON, Data, and so on….
It uses method chaining to set stubs up.

How to use

Stub HTTP Request

XCTest

import Replacer
import TestReplacer 

class SampleTests: XCTestCase {
    func testJSONFile() {
        // register a stub
        self.urlStub.url("echo.jsontest.com").json(["test": "data"])
        
        // load sample.json & register a stub.
        self.urlStub.json(filename: "sample")

        let expectation = self.expectation(description: "")
        
        let url = URL(string: "http://echo.jsontest.com/key/value/one/two")!
        URLSession(configuration: .default).dataTask(with: url) { data, _, _ in
            let json = try! JSONSerialization.jsonObject(with: data!, options: .allowFragments) as! [String: String]
            XCTAssert(json["test"] == "data")
            expectation.fulfill()
        }.resume()

        self.waitForExpectations(timeout: 0.02, handler: nil)
    }
}

Quick & Alamofire

class SampleSpecs: QuickSpec {
    override func spec() {
        describe("Quick compatibility test") {
            context("using JSON file") {
                beforeEach() {
                    // wait for 1.5s
                    self.urlStub.url("echo.jsontest.com/[a-z]+/.*")
                        .httpMethod(.post)
                        .json(["test": "data"])
                        .delay(1.5)
                }

                it("returns mock data") {
                    var json: [String: String]?

                    Alamofire.request("http://echo.jsontest.com/key/value/one/two", method: .post).responseJSON { response in
                        json = response.result.value as? [String: String]
                    }

                    // SessionManager is also OK.
                    // SessionManager.default.request("http://echo.jsontest.com/key/value/one/two").responseJSON { _ in }

                    expect(json?["test"]).toEventually(equal("data"))
                }
            }
        }
    }
}

Method Swizzling

import UIKit
import Replacer

@UIApplicationMain
class AppDelegate: UIResponder, UIApplicationDelegate {

    var window: UIWindow?

    func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplicationLaunchOptionsKey: Any]?) -> Bool {

        Replacer.replaceInstance(#selector(UIViewController.viewWillAppear(_:)),
                                 of: UIViewController.self,
                                 with: #selector(UIViewController.orig_viewWillAppear(_:)),
                                 of: UIViewController.self)

        return true
    }
}

extension UIViewController {
    func orig_viewWillAppear(_ animated: Bool) {
        orig_viewWillAppear(animated)

        print("swizzled")
    }
}

Installation

Carthage

github "tattn/Replacer"

CocoaPods

pod 'Replacer'

Documentation

• Stub Reference

Contributing

1. Fork it!
2. Create your feature branch: git checkout -b my-new-feature
3. Commit your changes: git commit -am 'Add some feature'
4. Push to the branch: git push origin my-new-feature
5. Submit a pull request :D

License

Replacer is released under the MIT license. See LICENSE for details.