Upgrade to Pro
— share decks privately, control downloads, hide ads and more …
Speaker Deck
Features
Speaker Deck
PRO
Sign in
Sign up for free
Search
Search
Network Testing in Swift with DVR
Search
Sam Soffes
October 08, 2015
Programming
0
6.5k
Network Testing in Swift with DVR
Walkthrough of how to use DVR and the design behind it. Given at Realm on 2015-10-08.
Sam Soffes
October 08, 2015
Tweet
Share
More Decks by Sam Soffes
See All by Sam Soffes
Starting a Mobile Design System
soffes
0
120
Building Functional Apps in Swift for iOS & OS X
soffes
5
13k
Go
soffes
2
600
Favorites
soffes
2
800
Seesaw — Under the Playground
soffes
2
410
Ubiquitously Connected to the World
soffes
0
200
API First, Then Apps
soffes
3
350
Building Realtime Apps
soffes
6
7.8k
Dispatch Awesome
soffes
8
930
Other Decks in Programming
See All in Programming
Scale out your Claude Code ~自社専用Agentで10xする開発プロセス~
yukukotani
9
2.5k
あまり知られていない MCP 仕様たち / MCP specifications that aren’t widely known
ktr_0731
0
290
GUI操作LLMの最新動向: UI-TARSと関連論文紹介
kfujikawa
0
1k
エンジニアのための”最低限いい感じ”デザイン入門
shunshobon
0
120
『リコリス・リコイル』に学ぶ!! 〜キャリア戦略における計画的偶発性理論と変わる勇気の重要性〜
wanko_it
1
580
MLH State of the League: 2026 Season
theycallmeswift
0
150
一人でAIプロダクトを作るための工夫 〜技術選定・開発プロセス編〜 / I want AI to work harder
rkaga
12
2.8k
サイトを作ったらNFCタグキーホルダーを爆速で作れ!
yuukis
0
430
Understanding Ruby Grammar Through Conflicts
yui_knk
1
120
実践!App Intents対応
yuukiw00w
1
330
MCPで実現するAIエージェント駆動のNext.jsアプリデバッグ手法
nyatinte
4
270
The state patternの実践 個人開発で培ったpractice集
miyanokomiya
0
140
Featured
See All Featured
Code Reviewing Like a Champion
maltzj
525
40k
Fight the Zombie Pattern Library - RWD Summit 2016
marcelosomers
234
17k
Improving Core Web Vitals using Speculation Rules API
sergeychernyshev
18
1.1k
Unsuck your backbone
ammeep
671
58k
Evolution of real-time – Irina Nazarova, EuRuKo, 2024
irinanazarova
8
890
Scaling GitHub
holman
462
140k
BBQ
matthewcrist
89
9.8k
Thoughts on Productivity
jonyablonski
69
4.8k
Making Projects Easy
brettharned
117
6.3k
No one is an island. Learnings from fostering a developers community.
thoeni
21
3.4k
GraphQLとの向き合い方2022年版
quramy
49
14k
How GitHub (no longer) Works
holman
315
140k
Transcript
DVR Networking tes-ng in Swi/.
Hi, I'm @soffes.
DVR is this thing I made when I worked at
Venmo.
Inspired by VCR for Ruby.
Records networking and plays it back in tests.
Using DVR
// Example XCTest func testTimeline() { let expectation = expectationWithDescription("Networking")
// Your network client let client = APIClient() client.getTimeline { success in XCTAssertTrue(success) expectation.fulfill() } waitForExpectationsWithTimeout(1, handler: nil) }
// DVR Session let dvr = Session(cassetteName: "timeline") // Pass
into initializer let client = APIClient(session: dir)
class APIClient { let session: NSURLSession init(session: NSURLSession = NSURLSession.sharedSession())
{ self.session = session } }
func getTimeline(completion: Bool -> Void) { let request = NSURLRequest(URL:
timelineURL) session.dataTaskWithRequest(request) { _, _, _ completion(true) }.resume() }
DVR Internals
class Session: NSURLSession { let cassetteName: String let backingSession: NSURLSession
init(cassetteName: StringbackingSession: NSURLSession = NSURLSession.sharedSession()) { self.cassetteName = cassetteName self.backingSession = backingSession super.init() } override func dataTaskWithRequest(request: NSURLRequest) -> NSURLSessionDataTask { return SessionDataTask(session: self, request: request) } }
Call resume() & then magic.
class SessionDataTask: NSURLSessionDataTask { override func resume() { // Playback
cassette on disk or record } }
Casse%es are stored as JSON.
{ "name" : "example", "interactions" : [ { "recorded_at" :
1434688721.440751, "request" : { "method" : "GET", "url" : "http:\/\/example.com" } "response" : { "body" : "hello", "status" : 200, "url" : "http:\/\/example.com\/", "headers" : { "Cache-Control" : "max-age=604800", "Content-Type" : "text\/plain", "Last-Modified" : "Fri, 09 Aug 2013 23:54:35 GMT", "Content-Length" : "5" } } } ] }
Why this over mocks?
Mocks are inherently fragile. You have to couple your tes7ng
code with the implementa7on details of your test. — Dave Abrahams, Protocol-Oriented Programming in Swi3
class DisabledSession: NSURLSession { override func dataTaskWithRequest(request: NSURLRequest, completionHandler: (NSData?,
NSURLResponse?, NSError?) -> Void) -> NSURLSessionDataTask? { XCTFail("Networking disabled") return nil } }
github.com/venmo/DVR
Thanks