[TDD] Apple Music API - ArtistAPIService를 만들고 테스트해보자

테스트 코드부터 작성하는 것이 감이 안와서 테스트 코드보다 먼저 ArtistAPIService를 작성해버렸다... 🙄

이전 포스팅에서 만들었던 ArtistAPIType을 이용하여...!!! 

 

	protocol ArtistAPIServiceProtocol {
	func fetchArtist(with id: String, completion: @escaping (Result<Artist?, APIError>) -> Void)
	func fetchArtists(with id: [String], completion: @escaping (Result<[Artist], APIError>) -> Void)
	}
	class ArtistAPIService: ArtistAPIServiceProtocol {
	func fetchArtist(with id: String, completion: @escaping (Result<Artist?, APIError>) -> Void) {
	let apiType = ArtistAPIType.fetchOne(id: id)
	guard let request = apiType.request else { return completion(.failure(.notValidRequest))}
	URLSession.shared.dataTask(with: request) { (data, response, error) in
	if let data = data {
	do {
	let artistResult = try JSONDecoder().decode(ArtistResult.self, from: data)
	completion(.success(artistResult.artists.first))
	} catch {
	completion(.failure(.notDecodingEnabled))
	}
	} else {
	completion(.failure(.notHasData))
	}
	}.resume()
	}
	func fetchArtists(with id: [String], completion: @escaping (Result<[Artist], APIError>) -> Void) {
	let apiType = ArtistAPIType.fetchMany(ids: id)
	guard let request = apiType.request else { return completion(.failure(.notValidRequest))}
	URLSession.shared.dataTask(with: request) { (data, response, error) in
	if let data = data {
	do {
	let artistResult = try JSONDecoder().decode(ArtistResult.self, from: data)
	completion(.success(artistResult.artists))
	} catch {
	completion(.failure(.notDecodingEnabled))
	}
	} else {
	completion(.failure(.notHasData))
	}
	}.resume()
	}
	}

view raw ArtistAPIService.swift hosted with ❤ by GitHub

 

물론 다음과 같이 Artist모델도 만들어줬다...!!! 

 

	struct ArtistResult: Decodable {
	let artists: [Artist]
	enum CodingKeys: String, CodingKey {
	case artists = "data"
	}
	}
	struct Artist: Decodable {
	let attributes: Attributes
	let relationships: Relationships
	}
	struct Attributes: Decodable {
	let genreNames: [String]
	let name: String
	}
	struct Relationships: Decodable {
	let albums: Albums
	}
	struct Albums: Decodable {
	let currentAlbums: [Album]
	let nextAlbumsPath: String
	enum CodingKeys: String, CodingKey {
	case currentAlbums = "data"
	case nextAlbumsPath = "href"
	}
	}
	struct Album: Decodable {
	let id: String
	let path: String
	enum CodingKeys: String, CodingKey {
	case id
	case path = "href"
	}
	}

view raw Artist.swift hosted with ❤ by GitHub

 

 

그리고 Apple Music API 홈페이지에 들어가서 해당 API에 해당하는 더미데이터를 복붙하여 넣어준 더미데이터 파일을 만들고 테스트 코드 있는 쪽에 넣어준다 BananaMusicTests 그룹안에 넣어주면 된다 (나의 토이프로젝트 이름은 BananaMusic이기때문...ㅎㅎ!! )

 

	//
	// ArtistDummyData.swift
	// BananaMusicTests
	import Foundation
	struct ArtistDummyData {
	static let fetchOneJsonString = """
	{
	"data": [
	{
	"attributes": {
	"genreNames": [
	"Rock"
	],
	"name": "Bruce Springsteen",
	"url": "https://itunes.apple.com/us/artist/bruce-springsteen/id178834"
	},
	"href": "/v1/catalog/us/artists/178834",
	"id": "178834",
	"relationships": {
	"albums": {
	"data": [
	{
	"href": "/v1/catalog/us/albums/1112053294",
	"id": "1112053294",
	"type": "albums"
	},
	{
	"href": "/v1/catalog/us/albums/1083046086",
	"id": "1083046086",
	"type": "albums"
	},
	{
	"href": "/v1/catalog/us/albums/1051321939",
	"id": "1051321939",
	"type": "albums"
	},
	{
	"href": "/v1/catalog/us/albums/1062111710",
	"id": "1062111710",
	"type": "albums"
	},
	{
	"href": "/v1/catalog/us/albums/1049523853",
	"id": "1049523853",
	"type": "albums"
	},
	{
	"href": "/v1/catalog/us/albums/1051327591",
	"id": "1051327591",
	"type": "albums"
	},
	{
	"href": "/v1/catalog/us/albums/1025011001",
	"id": "1025011001",
	"type": "albums"
	},
	{
	"href": "/v1/catalog/us/albums/1027452033",
	"id": "1027452033",
	"type": "albums"
	},
	{
	"href": "/v1/catalog/us/albums/987471714",
	"id": "987471714",
	"type": "albums"
	},
	{
	"href": "/v1/catalog/us/albums/955683364",
	"id": "955683364",
	"type": "albums"
	},
	{
	"href": "/v1/catalog/us/albums/918626472",
	"id": "918626472",
	"type": "albums"
	},
	{
	"href": "/v1/catalog/us/albums/947755049",
	"id": "947755049",
	"type": "albums"
	},
	{
	"href": "/v1/catalog/us/albums/924130802",
	"id": "924130802",
	"type": "albums"
	},
	{
	"href": "/v1/catalog/us/albums/928280298",
	"id": "928280298",
	"type": "albums"
	},
	{
	"href": "/v1/catalog/us/albums/891847015",
	"id": "891847015",
	"type": "albums"
	},
	{
	"href": "/v1/catalog/us/albums/843057439",
	"id": "843057439",
	"type": "albums"
	},
	{
	"href": "/v1/catalog/us/albums/857968854",
	"id": "857968854",
	"type": "albums"
	},
	{
	"href": "/v1/catalog/us/albums/797522110",
	"id": "797522110",
	"type": "albums"
	},
	{
	"href": "/v1/catalog/us/albums/791259770",
	"id": "791259770",
	"type": "albums"
	},
	{
	"href": "/v1/catalog/us/albums/741055385",
	"id": "741055385",
	"type": "albums"
	},
	{
	"href": "/v1/catalog/us/albums/748097215",
	"id": "748097215",
	"type": "albums"
	},
	{
	"href": "/v1/catalog/us/albums/860790154",
	"id": "860790154",
	"type": "albums"
	},
	{
	"href": "/v1/catalog/us/albums/635191145",
	"id": "635191145",
	"type": "albums"
	},
	{
	"href": "/v1/catalog/us/albums/604717239",
	"id": "604717239",
	"type": "albums"
	},
	{
	"href": "/v1/catalog/us/albums/507691647",
	"id": "507691647",
	"type": "albums"
	}
	],
	"href": "/v1/catalog/us/artists/178834/albums",
	"next": "/v1/catalog/us/artists/178834/albums?offset=25"
	}
	},
	"type": "artists"
	}
	]
	}
	"""
	static let fetchManyJsonString = """
	{
	"data": [
	{
	"attributes": {
	"genreNames": [
	"Rock"
	],
	"name": "Bruce Springsteen",
	"url": "https://itunes.apple.com/us/artist/bruce-springsteen/id178834"
	},
	"href": "/v1/catalog/us/artists/178834",
	"id": "178834",
	"relationships": {
	"albums": {
	"data": [
	{
	"href": "/v1/catalog/us/albums/1112053294",
	"id": "1112053294",
	"type": "albums"
	},
	{
	"href": "/v1/catalog/us/albums/1083046086",
	"id": "1083046086",
	"type": "albums"
	},
	{
	"href": "/v1/catalog/us/albums/1051321939",
	"id": "1051321939",
	"type": "albums"
	},
	{
	"href": "/v1/catalog/us/albums/1062111710",
	"id": "1062111710",
	"type": "albums"
	},
	{
	"href": "/v1/catalog/us/albums/1049523853",
	"id": "1049523853",
	"type": "albums"
	},
	{
	"href": "/v1/catalog/us/albums/1051327591",
	"id": "1051327591",
	"type": "albums"
	},
	{
	"href": "/v1/catalog/us/albums/1025011001",
	"id": "1025011001",
	"type": "albums"
	},
	{
	"href": "/v1/catalog/us/albums/1027452033",
	"id": "1027452033",
	"type": "albums"
	},
	{
	"href": "/v1/catalog/us/albums/987471714",
	"id": "987471714",
	"type": "albums"
	},
	{
	"href": "/v1/catalog/us/albums/955683364",
	"id": "955683364",
	"type": "albums"
	},
	{
	"href": "/v1/catalog/us/albums/918626472",
	"id": "918626472",
	"type": "albums"
	},
	{
	"href": "/v1/catalog/us/albums/947755049",
	"id": "947755049",
	"type": "albums"
	},
	{
	"href": "/v1/catalog/us/albums/924130802",
	"id": "924130802",
	"type": "albums"
	},
	{
	"href": "/v1/catalog/us/albums/928280298",
	"id": "928280298",
	"type": "albums"
	},
	{
	"href": "/v1/catalog/us/albums/891847015",
	"id": "891847015",
	"type": "albums"
	},
	{
	"href": "/v1/catalog/us/albums/843057439",
	"id": "843057439",
	"type": "albums"
	},
	{
	"href": "/v1/catalog/us/albums/857968854",
	"id": "857968854",
	"type": "albums"
	},
	{
	"href": "/v1/catalog/us/albums/797522110",
	"id": "797522110",
	"type": "albums"
	},
	{
	"href": "/v1/catalog/us/albums/791259770",
	"id": "791259770",
	"type": "albums"
	},
	{
	"href": "/v1/catalog/us/albums/741055385",
	"id": "741055385",
	"type": "albums"
	},
	{
	"href": "/v1/catalog/us/albums/748097215",
	"id": "748097215",
	"type": "albums"
	},
	{
	"href": "/v1/catalog/us/albums/860790154",
	"id": "860790154",
	"type": "albums"
	},
	{
	"href": "/v1/catalog/us/albums/635191145",
	"id": "635191145",
	"type": "albums"
	},
	{
	"href": "/v1/catalog/us/albums/604717239",
	"id": "604717239",
	"type": "albums"
	},
	{
	"href": "/v1/catalog/us/albums/507691647",
	"id": "507691647",
	"type": "albums"
	}
	],
	"href": "/v1/catalog/us/artists/178834/albums",
	"next": "/v1/catalog/us/artists/178834/albums?offset=25"
	}
	},
	"type": "artists"
	},
	{
	"attributes": {
	"genreNames": [
	"Rock"
	],
	"name": "Bob Dylan",
	"url": "https://itunes.apple.com/us/artist/bob-dylan/id462006"
	},
	"href": "/v1/catalog/us/artists/462006",
	"id": "462006",
	"relationships": {
	"albums": {
	"data": [
	{
	"href": "/v1/catalog/us/albums/1099677284",
	"id": "1099677284",
	"type": "albums"
	},
	{
	"href": "/v1/catalog/us/albums/1107753504",
	"id": "1107753504",
	"type": "albums"
	},
	{
	"href": "/v1/catalog/us/albums/1110230347",
	"id": "1110230347",
	"type": "albums"
	},
	{
	"href": "/v1/catalog/us/albums/1100815026",
	"id": "1100815026",
	"type": "albums"
	},
	{
	"href": "/v1/catalog/us/albums/1041144003",
	"id": "1041144003",
	"type": "albums"
	},
	{
	"href": "/v1/catalog/us/albums/1041169203",
	"id": "1041169203",
	"type": "albums"
	},
	{
	"href": "/v1/catalog/us/albums/1053284864",
	"id": "1053284864",
	"type": "albums"
	},
	{
	"href": "/v1/catalog/us/albums/1025066054",
	"id": "1025066054",
	"type": "albums"
	},
	{
	"href": "/v1/catalog/us/albums/945762927",
	"id": "945762927",
	"type": "albums"
	},
	{
	"href": "/v1/catalog/us/albums/963786366",
	"id": "963786366",
	"type": "albums"
	},
	{
	"href": "/v1/catalog/us/albums/952097786",
	"id": "952097786",
	"type": "albums"
	},
	{
	"href": "/v1/catalog/us/albums/949629284",
	"id": "949629284",
	"type": "albums"
	},
	{
	"href": "/v1/catalog/us/albums/935305035",
	"id": "935305035",
	"type": "albums"
	},
	{
	"href": "/v1/catalog/us/albums/925180674",
	"id": "925180674",
	"type": "albums"
	},
	{
	"href": "/v1/catalog/us/albums/924783871",
	"id": "924783871",
	"type": "albums"
	},
	{
	"href": "/v1/catalog/us/albums/940024611",
	"id": "940024611",
	"type": "albums"
	},
	{
	"href": "/v1/catalog/us/albums/941888332",
	"id": "941888332",
	"type": "albums"
	},
	{
	"href": "/v1/catalog/us/albums/934218391",
	"id": "934218391",
	"type": "albums"
	},
	{
	"href": "/v1/catalog/us/albums/933374405",
	"id": "933374405",
	"type": "albums"
	},
	{
	"href": "/v1/catalog/us/albums/923147717",
	"id": "923147717",
	"type": "albums"
	},
	{
	"href": "/v1/catalog/us/albums/919153202",
	"id": "919153202",
	"type": "albums"
	},
	{
	"href": "/v1/catalog/us/albums/902876924",
	"id": "902876924",
	"type": "albums"
	},
	{
	"href": "/v1/catalog/us/albums/900485117",
	"id": "900485117",
	"type": "albums"
	},
	{
	"href": "/v1/catalog/us/albums/890600867",
	"id": "890600867",
	"type": "albums"
	},
	{
	"href": "/v1/catalog/us/albums/889903193",
	"id": "889903193",
	"type": "albums"
	}
	],
	"href": "/v1/catalog/us/artists/462006/albums",
	"next": "/v1/catalog/us/artists/462006/albums?offset=25"
	}
	},
	"type": "artists"
	}
	]
	}
	"""
	}

view raw ArtistDummyData.swift hosted with ❤ by GitHub

 

그리고 실제 서버에서 주는 데이터가 아니라 이 더미데이터를 파싱하는 ArtistAPIServiceStub 을 만든다 (Stub, Mock, Spy 등등 다양한 용어들이 있던데 Stub이 정확한 용어가 아닐 수 도 있지만 일단 Stub이라고 하기!) 

 

	import Foundation
	@testable import BananaMusic
	struct ArtistAPIServiceStub: ArtistAPIServiceProtocol {
	func fetchArtist(with id: String, completion: @escaping (Result<Artist?, APIError>) -> Void) {
	let data = ArtistDummyData.fetchOneJsonString.data(using: .utf8)!
	do {
	let artistResult = try JSONDecoder().decode(ArtistResult.self, from: data)
	completion(.success(artistResult.artists.first))
	} catch {
	completion(.failure(.notDecodingEnabled))
	}
	}
	func fetchArtists(with id: [String], completion: @escaping (Result<[Artist], APIError>) -> Void) {
	let data = ArtistDummyData.fetchManyJsonString.data(using: .utf8)!
	do {
	let artistResult = try JSONDecoder().decode(ArtistResult.self, from: data)
	completion(.success(artistResult.artists))
	} catch {
	completion(.failure(.notDecodingEnabled))
	}
	}
	}

view raw ArtistAPIServiceStub.swift hosted with ❤ by GitHub

 

그다음 이제 Test코드를 만들어서 JSON 디코딩을 잘하는 지 테스트 해보자--!!

 

	import XCTest
	@testable import BananaMusic
	class ArtistAPIServiceTest: XCTestCase {
	var service: ArtistAPIServiceProtocol!
	override func setUp() {
	service = ArtistAPIServiceStub()
	}
	override func tearDown() {
	}
	func testFetchArtistDecoding() {
	service.fetchArtist(with: "") { (result) in
	switch result {
	case .success:
	XCTAssert(true, "디코딩 성공")
	case .failure:
	XCTFail("디코딩 실패")
	}
	}
	}
	func testFetchArtistsDecoding() {
	service.fetchArtists(with: []) { (result) in
	switch result {
	case .success:
	XCTAssert(true, "디코딩 성공")
	case .failure:
	XCTFail("디코딩 실패")
	}
	}
	}
	}

view raw ArtistAPIServiceTest.swift hosted with ❤ by GitHub

 

 

두개의 테스트 모두 테스트 성공이라고 나온다...!!! 

** 의문점 
- XCTFail은 있는데 왜 XCTSuccess는 없는 것일까?!?!?! 

- XCTAssert랑 XCTFail에 적은 메세지는 어디 나오는 것일까?!? 테스트 성공했을때 같이 나오는 것도 아니고 출력되지도 않던딩..?!? 

 

 

 

나의 첫 TDD는 테스트 코드가 먼저 되지 못했지만, 제대로 TDD를 했다면

모델만들고 더미데이터를 만들고, ServiceProtocol을 정의 한후 ArtistServiceStub을 먼저 작성하여 테스트를 돌리고 그 다음에 실제 서비스에서 쓸 ArtistService를 만드는 순서일 것이다...!!! 

 

그니까 나는

모델 -> ServiceProtocol ->  ArtistService -> 더미데이터 -> ArtistServiceStub -> 테스트

순서으로 만들었지만 

TDD로 한다면 

모델 -> 더미데이터 -> ServiceProtocol-> ArtistServiceStub -> 테스트 -> ArtistService 

이 순서가 되야하지 않을 까 싶다 

 

 

** 궁금점

- Stub으로 만들어서 테스트 후, Service를 만들면 Stub을 서비스로 바꿔서 다시 테스트를 돌려야되나?!?!? 

    override func setUp() {
        service = ArtistAPIServiceStub()
    }

위의 코드를 밑의 처럼 바꿔서..?!? 

    override func setUp() {
        service = ArtistAPIService()
    }