Code snippets for the post 'Help your user rate and review your iOS app!' (https://diamantidis.github.io/2020/04/05/app-reviews-for-iOS-apps)

Step1_Storage.swift

import Foundation

enum StorageKey: String {
    case lastVersionPromptedReview
    case dayOfFirstAction
    case actionCount
}

protocol Storage {
    func integer(forKey key: StorageKey) -> Int
    func set(_ value: Int, forKey key: StorageKey)
    func object(forKey key: StorageKey) -> Any?
    func set(_ value: NSDate, forKey key: StorageKey)
    func string(forKey key: StorageKey) -> String?
    func set(_ value: String, forKey key: StorageKey)
}

extension UserDefaults: Storage {
    func integer(forKey key: StorageKey) -> Int {
        return self.integer(forKey: key.rawValue)
    }

    func set(_ value: Int, forKey key: StorageKey) {
        self.set(value, forKey: key.rawValue)
    }

    func object(forKey key: StorageKey) -> Any? {
        return self.object(forKey: key.rawValue)
    }

    func set(_ value: NSDate, forKey key: StorageKey) {
        self.set(value, forKey: key.rawValue)
    }

    func string(forKey key: StorageKey) -> String? {
        return self.string(forKey: key.rawValue)
    }

    func set(_ value: String, forKey key: StorageKey) {
        self.set(value, forKey: key.rawValue)
    }
}

Step2_BundleType.swift

import Foundation

protocol BundleType {
    func object(forInfoDictionaryKey key: String) -> Any?
}

extension Bundle: BundleType {}

Step3_InAppReviewManager.swift

import Foundation

class InAppReviewManager {

    // MARK: - Initializers
    init(storage: Storage = UserDefaults.standard, bundle: BundleType = Bundle.main) {
        self.storage = storage
        self.bundle = bundle
    }

    // MARK: - Public methods
    func shouldAskForReview() -> Bool {

        // Count the number of actions
        var actionCount = storage.integer(forKey: .actionCount)
        actionCount += 1
        storage.set(actionCount, forKey: .actionCount)

        // Store the day of first action
        let dateOfFirstActionObj = storage.object(forKey: .dayOfFirstAction)
        if dateOfFirstActionObj == nil {
            storage.set(NSDate(), forKey: .dayOfFirstAction)
        }

        // Calculate if there have been three weeks since the first action
        let threeWeeksInSeconds: TimeInterval = 3 * 7 * 24 * 60 * 60
        let threeWeeksAgo = Date(timeIntervalSinceNow: -threeWeeksInSeconds)

        guard let dateOfFirstAction = dateOfFirstActionObj as? Date else {
            return false
        }

        let comparisonResult = dateOfFirstAction.compare(threeWeeksAgo)

        // Check if user has reviewed this version
        let bundleVersionKey = kCFBundleVersionKey as String
        guard let bundleVersion = bundle.object(forInfoDictionaryKey: bundleVersionKey) as? String else {
            return false
        }
        let lastVersion = storage.string(forKey: .lastVersionPromptedReview)

        guard case .orderedAscending = comparisonResult, actionCount >= 3, lastVersion == nil || lastVersion != bundleVersion else {
            return false
        }

        storage.set(bundleVersion, forKey: .lastVersionPromptedReview)
        return true
    }

    // MARK: - Private properties
    private let storage: Storage
    private let bundle: BundleType
}

Step4_SomeViewController.swift

import UIKit
import StoreKit      

...
       let manager = InAppReviewManager()
        if manager.shouldAskForReview() {
            DispatchQueue.main.asyncAfter(deadline: .now() + .seconds(2)) {
                SKStoreReviewController.requestReview()
            }
        }
...

Step5_MockStorage.swift

import Foundation

@testable import In_App_Review_Demo

class MockStorage: Storage {
    var actionCount: Int?
    var setActionCallback: ((_ count: Int)->Void)?

    var dayOfFirstAction: NSDate?
    var setDayCallback: ((_ day: NSDate)->Void)?

    var latestVersion: String?
    var setVersionCallback: ((_ version: String)->Void)?

    func integer(forKey key: StorageKey) -> Int {
        return actionCount ?? -1
    }

    func set(_ value: Int, forKey key: StorageKey) {
        setActionCallback?(value)
    }

    func object(forKey key: StorageKey) -> Any? {
        return dayOfFirstAction
    }

    func set(_ value: NSDate, forKey key: StorageKey) {
        setDayCallback?(value)
    }

    func string(forKey key: StorageKey) -> String? {
        return latestVersion
    }

    func set(_ value: String, forKey key: StorageKey) {
        setVersionCallback?(value)
    }
}

Step6_MockBundle.swift

import Foundation

@testable import In_App_Review_Demo

class MockBundle: BundleType {
    var version: String?
    func object(forInfoDictionaryKey key: String) -> Any? {
        return version
    }
}

Step7_InAppReviewManagerTests.swift

import XCTest

@testable import In_App_Review_Demo

class InAppReviewManagerTests: XCTestCase {

    // MARK: - Overriden methods
    override func setUp() {
        storage = MockStorage()
        bundle = MockBundle()
        sut = InAppReviewManager(storage: storage, bundle: bundle)
    }

    // MARK: - Test methods
    func testFirstTimeAction__ShouldNotShowReview() {
        // Arrange
        storage.actionCount = 0
        storage.dayOfFirstAction = nil
        storage.latestVersion = nil
        bundle.version = "1"

        let actionCountExpectation = expectation(description: "func `set(value:Int, forKey: StorageKey)` is called")
        storage.setActionCallback = { _ in
            actionCountExpectation.fulfill()
        }

        let dayExpectation = expectation(description: "func `set(value:NSDate, forKey: StorageKey)` is called")
        storage.setDayCallback = { _ in
            dayExpectation.fulfill()
        }

        let versionExpectation = expectation(description: "func `set(value:String, forKey: StorageKey)` is called")
        versionExpectation.isInverted = true
        storage.setVersionCallback = { _ in
            versionExpectation.fulfill()
        }

        // Act
        let response = sut.shouldAskForReview()

        // Assert
        XCTAssertFalse(response)
        waitForExpectations(timeout: 1, handler: nil)
    }

    func testThirdActionAfterThreeWeeksOnNewVersion__ShouldShowReview() {
        // Arrange
        storage.actionCount = 2
        storage.dayOfFirstAction = NSDate(timeIntervalSinceNow: -3 * 7 * 24 * 60 * 60 )
        storage.latestVersion = "1"
        bundle.version = "2"

        let actionCountExpectation = expectation(description: "func `set(value:Int, forKey: StorageKey)` is called")
        storage.setActionCallback = { _ in
            actionCountExpectation.fulfill()
        }

        let dayExpectation = expectation(description: "func `set(value:NSDate, forKey: StorageKey)` is called")
        dayExpectation.isInverted = true
        storage.setDayCallback = { _ in
            dayExpectation.fulfill()
        }

        let versionExpectation = expectation(description: "func `set(value:String, forKey: StorageKey)` is called")
        storage.setVersionCallback = { _ in
            versionExpectation.fulfill()
        }
        // Act
        let response = sut.shouldAskForReview()

        // Assert
        XCTAssertTrue(response)
        waitForExpectations(timeout: 1, handler: nil)
    }

    // MARK: - Private properties
    private var sut: InAppReviewManager!
    private var storage: MockStorage!
    private var bundle: MockBundle!
}