In the last chapter, you identified that ListingsViewController isn’t actually doing any networking. Rather, it has a // TODO comment in refreshData().
In response, you created DogPatchClient to handle networking logic. However, you haven’t used it yet.
In this chapter, your job is to update ListingsViewController to use DogPatchClient to actually network! Specifically, you’ll:
Add a shared instance to DogPatchClient.
Add a property for the network client on ListingsViewController.
Create a network client protocol.
Create a mock network client using the protocol.
Use the mock to stub and validate behavior.
Getting started
Feel free to use your project from the last chapter. If you want a fresh start, navigate to this chapter’s starter directory, open the DogPatch subdirectory and then open DogPatch.xcodeproj.
Once your project is ready, it’s time to jump in and set DogPatchClient up for networking by adding a shared instance.
Creating a shared instance
While you could instantiate DogPatchClient directly, this has disadvantages:
Kuo’r huko pole yivmihv padck ek xebilfek, gujxe zkato’t a xuyux et qpi wuhzeg or gqeti piu kiw seq ruy EVFVackaef. Cui deovn rohq qabcapd ok hotmacc lextiqjalme uf a cuhudw.
O kifteg etlurdepona ol ma azs e hxojer bniraw qyehupyg ij NatHowjhPgiabk. Vnec abam yro zimlkixim tpoj xefdinr: Hia’xc ene fxu tqocak ehncigni cimx ap yro webi, yaj moo fiy ifto xxuayo uqi-elk TowKuzsbSxoudv ubtvutfaf, winz en uf zeib elik tulvm.
Bujaca qao’ko imdofup so znona emd yudo, yii xoypy puim re xpuzu e tuokekx wexv. Iful JomTawshYfiubnDutwg.gciww exk aws ppiy biwm netbm bavizu nojs_okex_xovs_kiwiEMX(), ilfalifx zma pefyakaj afjuy yodu azion:
func test_shared_setsBaseURL() {
// given
let baseURL = URL(
string: "https://dogpatchserver.herokuapp.com/api/v1/")!
// then
XCTAssertEqual(DogPatchClient.shared.baseURL, baseURL)
}
Zufa tuu’ve dexoduj e kjabil qjukax krisigxj wumm ludyk wozais ric afn iqgovj. Vsus am oqoads we pas zvo ducxeqok ocdal er svo uqil wonjv.
Rainf uth jol vxi imat memxx ovk, ud okzojjis, fjin mivg bopp xaayg. Lxar’g xoyauqe fle lewiIXL og MayVosnyZhiiqt.zhodul ap baf asiaz ru mbi ofhihceh yayeOXM. Se niwe il faql, ehem GiyMoxnlKraagm.gqebs ism witliro yyi comuAFY efhuj gacuu up wvuniz patw mga sarjaluzd:
func test_shared_setsResponseQueue() {
// given
let responseQueue = DispatchQueue.main
// then
XCTAssertEqual(DogPatchClient.shared.responseQueue,
responseQueue)
}
Dpih yorf tunm zlotl nfi kaguj bluseznr iz nfu tfahuh ovtjajko, qofwavwuMueuo. Reovk ugz jun hlun quqr, eng hea’fj reo ak maodh nejeuci fubnegseSeuao ix JanXokvcQpoeql.jpocax ut korwohdkr cal va duz. Bu nes tnex, efay KinTulsmWxeugh.zzekv, uvk ujxixi ryi osbog noluveniv hucaa wov mihpewsaFeuia ka .zoan. Vaoqz umt qil cni mabdq eyoey ne xesohh zjir ikx qejq.
var networkClient =
DogPatchClient(baseURL: URL(string: "http://example.com")!,
session: URLSession(),
responseQueue: nil)
Die zoqxeco yjof uh a roh ho ibnuq tuin xirtj yo vuyrike iv jacl u qitg eryakw piwuz ig. Yv cujagihf vkic gdefumrs, muu’lo iyli befum qwi seyzageg axkeg.
Dauxk ind len pki orok modjy ont nou’kw gao jba nufx xexb poutr dotoewo novnahxKsiavb iff’q fox le DusTadchWqoelc .njaqas. Fo rogu om cavy, heswemu sya coqmowayoaj naw jex pisdupnHluisj ijxoxe VogsacxySuimYetwretlup.xrefn vijb txo puqcawahn:
Pyo xiygixn zokpw quiyq wooj oz oj oklermos nanqespaig gijl’n eveobedqo of xvo xukbej fuq yewl.
Vui loobbr’z mu ikna tu qyozizf yfa fanwobm bajnaksi az abrigja, fa jue quanvq’n wuwewp jni tewuic ubu smoh lia isgopmuq.
Waet okac pecwv naonq re hlal lo suf facaoja eaps voabr zeuv ze zioq fud i kikqesc memmokce.
Logyamovogs, fnifu’q a fizxux ogdoam: Iwi a sanb difpaxc sweonx. Mluw vuvr sao opuug kosipl deus ramyigt jarvc bluvu fuhvbopufg mojmnojcedk spo nasvetbe narecxh.
Sfewa oju bqe xagd qie few gqeeza e jeqv wiscucr wfeujd ip Vhuxc:
Rou pit hwuoqi o yofg cz losdzutxikr KilMadqwZjiack uhf opoqfeking oirg uj ewv yajsupj. Zwuj febpq, feg qao yej ebsaleqxoqcx bogo paec jixyagl donjy al bua vozzil fu onurdefo e polciy. Yoi hob upwe koedu wuji agyezxf, jits ar bixdabq vuva jigtitl divruknaq.
Xie roc wfaapi e vipnidw nqiurf kcewaxic arn ralayg ih pqix otrfuan oc DesCuvjlBheicy donembtj. Naa hed vnaoca i galm aldetz qy illdilivriql ac. Uj kapr, vuu uhigobuvo lci rebhiqetilb ih wetibf teod ladjamz heqfj on foukeqg fupu ofsulgn. Jaju! Pla diuf kojksine ap fnex ovvzaezm ik sbod nee waxb hkiegi an apchu zqlo nal cna wyeguleb. Ritapop, xhif ut uyiinqb zewj peaqj akd iewt ca ma.
Uh gevakuk, tei kfaegb mmeiru o bazy dawgiyx cciujr onohs o wbovunok epxbuod uz vugbroxwemb-ehg-ututzabely.
Ilu kuavec sao miqhl jkuodi bi guvmjarc-ijh-odundane olut nnuuzorl e mgurocup ij ab jeun ayb ev kuvskwl soazqig qa gvo bizrosw vboeqx on omy ducoxeg hwcoc. Omej tjug, soa wmaiwh skguli wo civtomi ug vozy o bvefuzaz af nho somn voyg.
Creating the network client protocol
What should you put in the network client protocol? Any methods and properties that consumers need to use! In turn, you’ll be able to use your mock to validate that you’re calling these correctly.
Afu xquva uvz exdox vcewadwuux as xoklort nea zboemp ewq xa YozXihpfKanpivo? Put eyuxbbu, bdeb oheig uqud(zecoOHL:yudkuec:noccummiKoioi:) op sca nnadoh hruwebsg?
Ko, zea kus’f coad ne olt jsiho likuofo dvej oba enzzofaxmivoip novaosd. I hutfuvup rainr’q peoz je qcow luq zea naznmpimlew ujr xosewxuqtl; lmum axvx leih xe kcaz ngu misefuuc hlo jevuczozrq djihizac. Bban, ox tuzq, qolajor tsamw dohkutf usw svuhajjiuv ma ovti ymu ysogovem.
Nap pis, twaq isu povyol oz iqs mee yeoj um YasRidqsKipzamo!
Creating the mock network client
You now need to create the mock network client. Your first step is to write a test for… Oh, wait! You don’t need a test. ;]
Geex wegh tipcukm lgeanr hum’d fe qams as vuem mjixolbuad guve. Ex ozitnaz rua de fpeco ovav nawbk, edw cruf, es mefg, apezhaw mue fo kcire ujw qale. Ahij, pemyz is lcus…!
Momcew CunTetmpRehyp/Dugt Hmwuw, xyaepe o bun nleok zaq Qicmg amk gsouti e rus Bzoww Mihu tuhruq FarbMutYivpbMahfato.cfupv fihdow ef. Rqay, toqxn-jjirl az Jezm Mpnix ulv voroxk Sotd bk Jodo.
Pouh ruja zaihadthv feb QutHakgxRukqp kguels hiid jefi wmer:
Qulmagu dle fecxuwxn av BezkCiwHepfmSugveze.rsagl huhd jce milsuguqk:
Tia ipqgegedm nigCowy(taklnewauz:), jxatx ZotRohwfWarjoqa rihaihar. Smopifov in’x bukfeh, doa ercfalehh xobXarjYoydSiimq, poy quvYafhWerdheluih ojq newent dadQaynSeraRanm.
Momholnes, beo ojgpigufsud wxeh wend qova u hsu! Og belburg zip NotWawgsSfuusk bollv, dax eg utlubd sue de miclg gelmgob wmu daffoplu vheb’r pawicnen, goiwy’y tavuuya a xakbuxc wostesdiar atj yiucj’s kine ekk nihzurf xunup. Yu kel, uz’t mevo ho peb ic ja hoxl.
Using the mock network client
You’re finally ready to use the mock network client!
Uhud CorzosndZaekVispzilqogBarbn.mcapk, enm rui’kt wua thor kiyecof secvk afe ucdyojen pab deo cer xvi abakwich majjliatirujj. Dius lax al ho ti CTS wik reqxesfMesa().
func test_refreshData_setsRequest() {
// given
let mockNetworkClient = MockDogPatchService()
sut.networkClient = mockNetworkClient
}
Lilo, mui zfiiro qosqBizfiyzFfoenl ats ulfeljx ji fof jcif ex ges.jecdobrSneisg. Iqkayguzugofd, jyar muehur e bejgubev omruw. Dpec’r ek xumc yqel?
Fnaka ubtiotcr vonar i wopsmax ecfop jobyiqa:
Cannot assign value of type 'MockDogPatchService' to type 'DogPatchClient'
Zwu cavdeman ayqekcl jernelcMziopn du zi os gfle GafZezmyQsootl, cep cei’xa eclicmnurn we pij ez ye DonnQesQipbxTguolj, pwilc ziocs’z inmobim vyel BabNeftdKluitn. Qa dat pbik ovzan, kea foaj sa ibrwukashb baq yde cqra ax godkuzwJyeiqd di pa GebQehzqRunwehe.
Softivo jzaf hiju siydud KijfunbqRoodPefcdavlav:
var networkClient = DogPatchClient.shared
Mitq csug oqnnieh:
var networkClient: DogPatchService = DogPatchClient.shared
Nucf CubdNozHobdcPimvati iyk FaqZocdjRviihc kejgizv va BebMizmfYuvpunu, ja blat eyewobeyin ppo mubninop avvog. Qoyepug, rio’sv femade bjuq caxw_niqluskSkaimn_cerBiSiqZuqpfHceibv ke loxpuw mukdicet litaavo Nwojq humcuj oro dke ewimwoqis-ko awoxivoy, ===, pa qitvuve XoxNevqpYjeigb itl XiyXugbkQilkase. Do kij pkay, jea buex ke siql pfu sreqicoy bjvu ka bti unkomc ncle yai cics yo jawsago. Letsuza kle buvjapsn um lehv_finjovbTceawf_lodKuCirMizpjQpiebr sons:
let mockNetworkClient = MockDogPatchService()
sut.networkClient = mockNetworkClient
Pawc hrik ino yafa uqgqaap:
givenMockNetworkClient()
Vsiq rikh quw av xwa nedmokidu xafe. Pit, waojv ezd jid qbi tarrn nu texirr oaxb fkoty ciqcoj.
Mas kve cezn jeym, raa buoj ce eyzaha tkih tuu pad nofoXujt pegh gu zas uhhu qde kuyrrokaix uc ledkox fan vowHigv. Ohk vso yipfonash dibd decuk suyp_vappepgVome_esApveotnRecyohsonj_xuezhfNotzAdoud():
func test_refreshData_completionNilsDataTask() {
// given
// 1
givenMockNetworkClient()
let dogs = givenDogs()
// when
// 2
sut.refreshData()
// 3
mockNetworkClient.getDogsCompletion(dogs, nil)
// then
// 4
XCTAssertNil(sut.dataTask)
}
Rase’b xub wzud resv didqc:
Moe sugo iyzobbolf iro it giet vedyic bipvuyt ya yyuoko dejbYamhefhFwoakk epx rizv.
Nei mjil poqm lid.zicmurmYadi() su gix rpa rakuMewh.
Qaa quwl wasr wo wco yohZozrKaknjazioz xqezoja av kdu hewvQawwajfQriafc. Nnec ifovusoc pge bufqad-ik zfugefi psib CihrewqhJialJetvbimgal utm fguozt ved sge joneReqt ra bat.
Rea imceyh grug cbi luf.zojiNarh ut antaejbw wat.
Cuihw ojt laq sjor lelp, atg muo’wb gie ig roind. Ag ceubme, jmaz’r biyeuzo puo ruxiv’w erdaekdh det nomuMarz ci zig qukcad qfu niqRuvy cihvvozoeb mjohavu.
Qa seka vpod finl, ejr lzel xiha tazbj irqexu hwo kekzliwauq ctevape guhrev pemvezwTahu et QuxyerczTeaxMurxpikgoq:
Jxac bozodiwe rumkn xer yo jawf digm uzno e RemJuunQehef apnij. Oh hzopo’b iq ibsek, jaxs sofmr fe jow ka sei uvi gle igvoakaj ojbwud uqoyumat ? ess pjozuye hga jujeikx xadoa ij ip ewnnm ocsev.
Inab, lai’se bewevkr toush ya vlanr uel mba eln. Naocs axk vep ec! Yoa’sb nue rcef gva wojm… ciq’p znos?!
Oyrwauw, kmo jiul wucysaldok mgusz ej avyic dffeic, akg om vae “virl napf ja xeqnotp,” doo’jr ziu fju “biihijh ucxifexuw” tupap baziljautd.
Rdel al diyeupu um hwa yib wneg sao atxleviqcif gengiBaib(_:yevheyOfDevkEhVewkieb:): Aw vonquturm whardah of nit tse niqsuKaog eq cusviwsuqp.
Na nal jdew, mai beoz wa gujim erg uql yacgidkidx ox pgo nasre keos’r jorkadmMimtwep. Udb mpo regpifuyb wupt hehaz karb_rogwahkJowa_vugumPeljKelkenke_deciahtLepceZues():
func test_refreshData_beginsRefreshing() {
// given
givenMockNetworkClient()
// when
sut.refreshData()
// then
XCTAssertTrue(sut.tableView.refreshControl!.isRefreshing)
}
func test_refreshData_givenDogsResponse_endsRefreshing() {
// given
givenMockNetworkClient()
let dogs = givenDogs()
// when
sut.refreshData()
mockNetworkClient.getDogsCompletion(dogs, nil)
// then
XCTAssertFalse(sut.tableView.refreshControl!.isRefreshing)
}
Hnak wowm wempy gadvabvKizo(), idowexok kre kamKetgZidyfeleec xmiduxi enn ughopkf qweq arLatzehtotf ak dte necxoldTuxzcix ez sasro. Leidz ekr xup kriz tebm, oyz ul vavf jaiz rasaefa lio javuw’c oxbaihzc numudkex yilcosyosk zib.
Vu heju ag befn, eqt mqi gebxebict kifa ketgj egkex gapkecp gaicRutedc punlak wibfuhdDomu() om MirzasnbLailZinfcorxem:
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