iOSGiphyCodeChallenge/LiveLikeGiphyChallenge/LiveLikeGiphyChallengeTests/LiveLikeGiphyChallengeTests.swift

//
//  LiveLikeGiphyChallengeTests.swift
//  LiveLikeGiphyChallengeTests
//
//  Created by Irina Smokvarska on 1/30/22.
//

import XCTest
@testable import LiveLikeGiphyChallenge

class LiveLikeGiphyChallengeTests: XCTestCase {
  
  var urlSession: URLSession!
  
  override func setUpWithError() throws {
    // Set url session for mock networking
    let configuration = URLSessionConfiguration.ephemeral
    configuration.protocolClasses = [MockURLProtocol.self]
    urlSession = URLSession(configuration: configuration)
  }
  
  func testFetchGifsByString_retrieveSearchedGif_successfullyReturnsSearchedGifData() async throws {
    let searchString = "Adventure%20Time%20Morning"
    let chunk = 1
    
    //The problem with the API here is that it doesn't always return this GIF with the exact same search string
    let expectedJSON = """
  [
      { "type": "gif",
      "id": "KFOqUTRI8H26s",
      "url": "https://giphy.com/gifs/KFOqUTRI8H26s",
      "title": "Adventure Time Morning GIF"
      }
  ]
  """
 
    let mockData = Data(expectedJSON.utf8)
    MockURLProtocol.requestHandler = { request in
      (HTTPURLResponse(), mockData)
    }
    
    let service = FetchGiphyAPI()
    service.urlSession = urlSession
    let gif = try await service.fetchGifsBy(string: searchString, chunk: chunk)
    XCTAssertEqual(1, gif.count, "The search result should show 1 GIF")
  }
  
  func testFetchGifsByString_errorWhileRetrievingSearchedGif_failedSearchedGifData() async throws {
    let searchString = "Adventure%20Time%20Morning"
    let chunk = -1
    let expectedJSON = """
  [
      { "type": "gif",
      "id": "KFOqUTRI8H26s",
      "url": "https://giphy.com/gifs/KFOqUTRI8H26s",
      "title": "Adventure Time Morning GIF"
      }
  ]
  """
 
    let mockData = Data(expectedJSON.utf8)
    MockURLProtocol.requestHandler = { request in
      (HTTPURLResponse(), mockData)
    }
    
    let service = FetchGiphyAPI()
    service.urlSession = urlSession
    let gif = try await service.fetchGifsBy(string: searchString, chunk: chunk)
    XCTAssertEqual([], gif, "The search result should be empty")
  }
  
  func testFetchTrendingGifs_successfullyRetrievesTreningGifs() async throws {
    let service = FetchGiphyAPI()
    service.urlSession = urlSession
   
    let gifs = try await service.fetchTrendingGifs(chunk: 20)
    XCTAssertFalse(gifs.isEmpty, "We should get gifs")
  }
}