哈Ha！我向您介绍raywenderlich.com上 Shai Mishali 撰写的文章“测试RxSwift代码”的翻译。

从概念上讲，使用RxSwift编写反应式应用程序与以“常规方式”编写应用程序有所不同。它不同于在这个意义上，在你的应用程序中的对象通常不会有一个明确的意义，相反，他们会通过代表的流值在时间轴上，被称为RxSwift Observable。本文将为您提供测试RxSwift代码的关键。

Observable-一种强大的机制，使您作为开发人员能够响应更改，并确保应用程序的状态始终是最新的。加上它提供的所有好处，测试Observable并不是一件简单的任务，不仅仅是简单地将XCTAssert用于普通值。但请放心-本文将指导您成为测试RxSwift的专家！

本文将教您如何为Observable线程创建单元测试。您将学习一些测试RxSwift代码的可用技术，以及一些技巧。开始吧。

注意：本文假定您已经熟悉RxSwift以及如何使用XCTest编写简单的测试。

入门

当您需要更改内容时，反应性应用程序的性能很好，因此我们将仅使用此类应用程序。

下载启动程序项目。您将找到本教程的入门项目：Raytronome是一个节拍器应用程序，可用于练习音乐。如您所知，由于节拍器会随着时间的推移而工作，因此您必须看到许多可以测试的逻辑。

Raytronome.xcworkspace. Main.storyboard. , .

. Play . (Signature) (Tempo).

UIViewController — MetronomeViewController.swift, MetronomeViewModel.swift -, .

Observable

RxSwift Observable .

, .

; . Observable , , () .

, :

,
. ""

, . , MetronomeViewModel, ViewModel - .

MetronomeViewModel.swift. ViewModel , : , ( ), , , , ,

UI. :

4
4/4
120
Play/Pause isPlaying
, , .
"" .
.even .odd —

RxSwift, RxBlocking RxTest. .

RxBlocking

RaytronomeTests.swift.

; RxSwift, RxCocoa, RxTest RxBlocking, viewModel setUp() MetronomeViewModel

, 4. , , . RxBlocking!

RxBlocking — RxSwift, : Observable BlockingObservable, Observable , .

, — , completed error —

RxBlocking , :

toArray(): .
first(): .
last(): .

, first().

RaytronomeTests:

func testNumeratorStartsAt4() throws {
  XCTAssertEqual(try viewModel.numeratorText.toBlocking().first(), "4")
  XCTAssertEqual(try viewModel.numeratorValue.toBlocking().first(), 4)
}

func testDenominatorStartsAt4() throws {
  XCTAssertEqual(try viewModel.denominatorText.toBlocking().first(), "4")
}

toBlocking() BlockingObservable, first() . XCTAssert .

, throws, RxBlocking . throws try! .

Command-U

signatureText 4/4, tempoText 120 BPM.

func testSignatureStartsAt4By4() throws {
  XCTAssertEqual(try viewModel.signatureText.toBlocking().first(), "4/4")
}

func testTempoStartsAt120() throws {
  XCTAssertEqual(try viewModel.tempoText.toBlocking().first(), "120 BPM")
}

RxBlocking

, RxBlocking , "" . , :

, , , , RxBlocking . , — — RxBlocking
RxBlocking . Observable , BlockingObservable .
, , RxBlocking , .
RxBlocking , .

. : Play/Pause isPlaying, (tappedPlayPause ). .

RxTest

, RxBlocking , , , .

RxTest!

RxTest RxBlocking, , , . - , — TestScheduler.

— RxSwift, , ,

RxSwift , .

: " ?"

RxTest — TestScheduler — . , Observable Observer, "" .

— .

TestScheduler. DisposeBag Disposable . viewModel :

var scheduler: TestScheduler!
var disposeBag: DisposeBag!

, setUp(), TestScheduler DisposeBag :

scheduler = TestScheduler(initialClock: 0)
disposeBag = DisposeBag()

TestScheduler initialClock, " " . DisposeBag . .

"" Play/Pause , isPlaying .

Observable "" tappedPlayPause.
Observer' isPlaying.
.

, !

. RxTest-:

func testTappedPlayPauseChangesIsPlaying() {
  // 1
  let isPlaying = scheduler.createObserver(Bool.self)

  // 2
  viewModel.isPlaying
    .drive(isPlaying)
    .disposed(by: disposeBag)

  // 3
  scheduler.createColdObservable([.next(10, ()),
                                  .next(20, ()),
                                  .next(30, ())])
           .bind(to: viewModel.tappedPlayPause)
           .disposed(by: disposeBag)

  // 4
  scheduler.start()

  // 5
  XCTAssertEqual(isPlaying.events, [
    .next(0, false),
    .next(10, true),
    .next(20, false),
    .next(30, true)
  ])
}

, . :

TestScheduler TestableObserver , Observable — Bool. Observaer — events, .
drive() "" viewModel.isPlaying TestableObserver. "" .
Observable, "" tappedPlayPause. , Observable, TestableObservable, TestScheduler "" .
start() .
XCTAssertEqual RxTest, , isPlaying , . 10, 20 30 , , 0 — isPlaying.

? : viewModel . , .

Command-u. 5 .

, 0, 10, 20 30 , .

RxTest (Date) , VirtualTimeUnit ( Int).

RxSwift — TestScheduler .

, — , , , 10 10 , . .

, TestScheduler, ?

func testModifyingNumeratorUpdatesNumeratorText() {
  let numerator = scheduler.createObserver(String.self)

  viewModel.numeratorText
           .drive(numerator)
           .disposed(by: disposeBag)

  scheduler.createColdObservable([.next(10, 3),
                                  .next(15, 1)])
           .bind(to: viewModel.steppedNumerator)
           .disposed(by: disposeBag)

  scheduler.start()

  XCTAssertEqual(numerator.events, [
    .next(0, "4"),
    .next(10, "3"),
    .next(15, "1")
  ])
}

func testModifyingDenominatorUpdatesNumeratorText() {
  let denominator = scheduler.createObserver(String.self)

  viewModel.denominatorText
           .drive(denominator)
           .disposed(by: disposeBag)

  // Denominator () -  2   `steppedDenominator + 1`.
  // f(1, 2, 3, 4) = 4, 8, 16, 32
  scheduler.createColdObservable([.next(10, 2),
                                  .next(15, 4),
                                  .next(20, 3),
                                  .next(25, 1)])
          .bind(to: viewModel.steppedDenominator)
          .disposed(by: disposeBag)

  scheduler.start()

  XCTAssertEqual(denominator.events, [
    .next(0, "4"),
    .next(10, "8"),
    .next(15, "32"),
    .next(20, "16"),
    .next(25, "4")
  ])
}

func testModifyingTempoUpdatesTempoText() {
  let tempo = scheduler.createObserver(String.self)

  viewModel.tempoText
           .drive(tempo)
           .disposed(by: disposeBag)

  scheduler.createColdObservable([.next(10, 75),
                                  .next(15, 90),
                                  .next(20, 180),
                                  .next(25, 60)])
           .bind(to: viewModel.tempo)
           .disposed(by: disposeBag)

  scheduler.start()

  XCTAssertEqual(tempo.events, [
    .next(0, "120 BPM"),
    .next(10, "75 BPM"),
    .next(15, "90 BPM"),
    .next(20, "180 BPM"),
    .next(25, "60 BPM")
  ])
}

testModifyingNumeratorUpdatesNumeratorText: , .
testModifyingDenominatorUpdatesNumeratorText: , .
testModifyingTempoUpdatesTempoText: ,

, , . , 3, 1. , numeratorText "4" ( ), "3", , , "1".

, denominatorText

, BPM

Command-U, 8 . !

, !

. :

func testModifyingSignatureUpdatesSignatureText() {
  // 1
  let signature = scheduler.createObserver(String.self)

  viewModel.signatureText
           .drive(signature)
           .disposed(by: disposeBag)

  // 2
  scheduler.createColdObservable([.next(5, 3),
                                  .next(10, 1),

                                  .next(20, 5),
                                  .next(25, 7),

                                  .next(35, 12),

                                  .next(45, 24),
                                  .next(50, 32)
                                ])
           .bind(to: viewModel.steppedNumerator)
           .disposed(by: disposeBag)

  // Denominator () -  2   `steppedDenominator + 1`.
  // f(1, 2, 3, 4) = 4, 8, 16, 32
  scheduler.createColdObservable([.next(15, 2), // switch to 8ths
                                  .next(30, 3), // switch to 16ths
                                  .next(40, 4)  // switch to 32nds
                                ])
           .bind(to: viewModel.steppedDenominator)
           .disposed(by: disposeBag)

  // 3
  scheduler.start()

  // 4
  XCTAssertEqual(signature.events, [
    .next(0, "4/4"),
    .next(5, "3/4"),
    .next(10, "1/4"),

    .next(15, "1/8"),
    .next(20, "5/8"),
    .next(25, "7/8"),

    .next(30, "7/16"),
    .next(35, "12/16"),

    .next(40, "12/32"),
    .next(45, "24/32"),
    .next(50, "32/32")
  ])
}

! , , . steppedNumerator steppedDenominator , signatureText .

. 9 !

, .

4/4
24/32.
"-" ; 16/16, 8/8, , , 4/4, 24/16, 24/8 24/4 — .

: , ,

func testModifyingDenominatorUpdatesNumeratorValueIfExceedsMaximum() {
  // 1
  let numerator = scheduler.createObserver(Double.self)

  viewModel.numeratorValue
           .drive(numerator)
           .disposed(by: disposeBag)

  // 2

  // Denominator () -  2   `steppedDenominator + 1`.
  // f(1, 2, 3, 4) = 4, 8, 16, 32
  scheduler.createColdObservable([
      .next(5, 4), // switch to 32nds
      .next(15, 3), // switch to 16ths
      .next(20, 2), // switch to 8ths
      .next(25, 1)  // switch to 4ths
      ])
      .bind(to: viewModel.steppedDenominator)
      .disposed(by: disposeBag)

  scheduler.createColdObservable([.next(10, 24)])
           .bind(to: viewModel.steppedNumerator)
           .disposed(by: disposeBag)

  // 3
  scheduler.start()

  // 4
  XCTAssertEqual(numerator.events, [
    .next(0, 4), //  4/4
    .next(10, 24), //  24/32
    .next(15, 16), //  16/16
    .next(20, 8), //  8/8
    .next(25, 4) //  4/4
  ])
}

, , ! :

, TestableObserver "" numeratorValue
, . 32, 24 ( ). 24/32. , numeratorValue.
schelduer
numeratorValue

! Command-U:

XCTAssertEqual failed: ("[next(4.0) @ 0, next(24.0) @ 10]") is not equal to ("[next(4.0) @ 0, next(24.0) @ 10, next(16.0) @ 15, next(8.0) @ 20, next(4.0) @ 25]") -

! .

, numeratorValue 24, , 24/16 24/4. :

, 4/8.
, 7/8.
. 4/4, 7/4 — !

, . :]

MetronomeViewModel.swift , numeratorValue:

numeratorValue = steppedNumerator
  .distinctUntilChanged()
  .asDriver(onErrorJustReturn: 0)

numeratorValue = steppedNumerator
  .distinctUntilChanged()
  .asDriver(onErrorJustReturn: 0)

steppedNumerator , steppedNumerator maxNumerator .

Command-U, 10 . !

viewModel. , 78%. !

: , Edit Scheme... - , , Tests, Options Code Coverage. Gather coverage for some targets Raytronome . Report Navigator

, . — .

, /, , ( )

— 32. RaytronomeTests.swift :

func testBeatBy32() {
  // 1
  viewModel = MetronomeViewModel(initialMeter: Meter(signature: "4/32"),
                                 autoplay: true,
                                 beatScheduler: scheduler)

  // 2
  let beat = scheduler.createObserver(Beat.self)
  viewModel.beat.asObservable()
    .take(8)
    .bind(to: beat)
    .disposed(by: disposeBag)

  // 3
  scheduler.start()

  XCTAssertEqual(beat.events, [])
}

. - :

viewModel . 4/32, , tappedPlayPause .
. , viewModel SerialDispatchQueueScheduler , TestScheduler, , .
TestableObserver Beat 8 beat. 8 — , , .
scheduler. , , , — .

Command-U. :

XCTAssertEqual failed: ("[next(first) @ 1, next(regular) @ 2, next(regular) @ 3, next(regular) @ 4, next(first) @ 5, next(regular) @ 6, next(regular) @ 7, next(regular) @ 8, completed @ 8]") is not equal to ("[]") —

, , ? 1 8.

, - , 4/32 4/4. , .

Meter(signature: "4/32") Meter(signature: "4/4") Command-U. - - .

, ! , - , . , ? -, VirtualTimeUnit, .

120 BPM, 4 ( 4/4), 0.5 . 32, 0.0625 .

, — , TestScheduler , VirtualTimeUnit.

resolution . resolution — TestScheduler 1.

0.0625/1 1, 0.5/1 1, .

, resolution, .

viewModel, , :

scheduler = TestScheduler(initialClock: 0, resolution: 0.01)

resolution

resoulution

4/32 viewModel Command-U.

, .

XCTAssertEqual failed: ("[next(first) @ 6, next(regular) @ 12, next(regular) @ 18, next(regular) @ 24, next(first) @ 30, next(regular) @ 36, next(regular) @ 42, next(regular) @ 48, completed @ 48]") is not equal to ("[]") —

6. XCTAssertEqual :

XCTAssertEqual(beat.events, [
  .next(6, .first),
  .next(12, .regular),
  .next(18, .regular),
  .next(24, .regular),
  .next(30, .first),
  .next(36, .regular),
  .next(42, .regular),
  .next(48, .regular),
  .completed(48)
])

Command-U, , . !

- 4/4 .

func testBeatBy4() {
  scheduler = TestScheduler(initialClock: 0, resolution: 0.1)

  viewModel = MetronomeViewModel(initialMeter: Meter(signature: "4/4"),
                                 autoplay: true,
                                 beatScheduler: scheduler)

  let beat = scheduler.createObserver(Beat.self)
  viewModel.beat.asObservable()
    .take(8)
    .bind(to: beat)
    .disposed(by: disposeBag)

  scheduler.start()

  XCTAssertEqual(beat.events, [
    .next(5, .first),
    .next(10, .regular),
    .next(15, .regular),
    .next(20, .regular),
    .next(25, .first),
    .next(30, .regular),
    .next(35, .regular),
    .next(40, .regular),
    .completed(40)
  ])
}

— , resolution, 0.1, 4.

Command-U, , 12 !

, , 99.25% MetronomeViewModel, . : beatType.

beatType — , , , beatType .even .odd. . , , :

func testBeatTypeAlternates() {
  scheduler = TestScheduler(initialClock: 0, resolution: 0.1)

  viewModel = MetronomeViewModel(initialMeter: Meter(signature: "4/4"),
                                 autoplay: true,
                                 beatScheduler: scheduler)

  let beatType = scheduler.createObserver(BeatType.self)
  viewModel.beatType.asObservable()
    .take(8)
    .bind(to: beatType)
    .disposed(by: disposeBag)

  scheduler.start()

  XCTAssertEqual(beatType.events, [
    .next(5, .even),
    .next(10, .odd),
    .next(15, .even),
    .next(20, .odd),
    .next(25, .even),
    .next(30, .odd),
    .next(35, .even),
    .next(40, .odd),
    .completed(40)
  ])
}

?

, . , RxSwift. RxBlocking , RxTest .

, Scheduler, TestScheduler .

在RxSwift和RxBlocking中都可以学到更多东西 -它们的内部工作，运算符等。最好的选择是官方的RxSwift文档以及RxBlocking运算符列表。

如果您对文章的内容有任何疑问或评论-欢迎发表评论或在原始文章的讨论中。谢谢阅读！警告，本文摘自raywenderlich.com的文章。

RxSwift代码的单元测试

入门

Observable

RxBlocking

RxBlocking

RxTest

?

More articles: