単体テストのハジメ

୯ମςετͷϋδϝ !ZPLPZBT UXJUUFS*%ZPLPZBT

ࣗݾ঺հ ˙ OBNFZPLPZBT ˙ UXJUUFS*%ZPLPZBT ˙ KPCגࣜձࣾNJYJͰJ04ΤϯδχΞ΍͍ͬͯ·͢

୯ମςετͷൃද͕গͳ͍ͱ ฉ͍ͨͷͰɺ ୯ମςετͷ࿩Λ͠·͢

ʮςετ͍ͨ͜͠ͱʯ ͸ԿͰ͠ΐ͏͔

doSomething(x) Ҿ਺ ໭Γ஋ ςετ͍ͨ͜͠ͱ ˙ ᶃ໌ࣔతͳೖग़ྗ

doSomething(x) Ҿ਺ ໭Γ஋ ςετ͕ॻ͖΍͍͢ ςετ͍ͨ͜͠ͱ ˙ ᶃ໌ࣔతͳೖग़ྗ

ςετ͍ͨ͜͠ͱ ˙ ᶄ҉໧తͳೖग़ྗ େҬม਺ͳͲ ଞͷςετ͕յ͔͢΋ ଞͷςετΛյ͔͢΋ େҬม਺ͳͲ doSomething(x) Ҿ਺ ໭Γ஋

ςετ͍ͨ͜͠ͱ ˙ ᶄ҉໧తͳೖग़ྗ େҬม਺ͳͲ ଞͷςετ͕յ͔͢΋ ଞͷςετΛյ͔͢΋ େҬม਺ͳͲ doSomething(x) Ҿ਺ ໭Γ஋
ςετ͕ॻ͖΍͍͢ʜ

ςετ͍ͨ͜͠ͱ ˙ ҉໧తͳೖग़ྗ େҬม਺ͳͲ େҬม਺ͳͲ doSomething(x) Ҿ਺ ໭Γ஋ ଞͷςετ͕յ͔͢΋ ଞͷςετΛյ͔͢΋

ͭΒ͍

ྫ͑͹Ͳ͏͍͏ςετʁ

҉໧తͳೖग़ྗͷςετྫ ˙ 6TFS%FGBVMUT͔Βऔಘͨ͠஋Λ࢖͏ؔ਺Λςετ͢Δ৔߹ class HogeTests: XCTestCase { func testHoge() {
UserDefaults.resetStandardUserDefaults() let testValue = 10 UserDefaults.standard.set(testValue, forKey: "hoge") // something to do... UserDefaults.standard.removeObject(forKey: "hoge") } }

class HogeTests: XCTestCase { func testHoge() { UserDefaults.resetStandardUserDefaults() let testValue
= 10 UserDefaults.standard.set(testValue, forKey: "hoge") // something to do... UserDefaults.standard.removeObject(forKey: "hoge") } } ҉໧తͳೖग़ྗͷςετྫ ˙ 6TFS%FGBVMUT͔Βऔಘͨ͠஋Λ࢖͏ؔ਺Λςετ͢Δ৔߹ ຊମίʔυɺ΋͘͠͸ଞͷςετ͔Β มߋ͞Ε͍ͯΔՄೳੑ͕͋ΔͷͰɺ 6TFS%FGBVMUTΛॳظঢ়ଶʹ͔ͯ͠Βελʔτ

= 10 UserDefaults.standard.set(testValue, forKey: "hoge") // something to do... UserDefaults.standard.removeObject(forKey: "hoge") } } ҉໧తͳೖग़ྗͷςετྫ ˙ 6TFS%FGBVMUT͔Βऔಘͨ͠஋Λ࢖͏ؔ਺Λςετ͢Δ৔߹ ςετΛߦ͏ͨΊʹʮࣄલʹೖ͍ͬͯͯཉ͍͠஋ʯΛ 6TFS%FGBVMUTʹ௚઀ॻ͖ࠐΉ

= 10 UserDefaults.standard.set(testValue, forKey: "hoge") // something to do... UserDefaults.standard.removeObject(forKey: "hoge") } } ҉໧తͳೖग़ྗͷςετྫ ˙ 6TFS%FGBVMUT͔Βऔಘͨ͠஋Λ࢖͏ؔ਺Λςετ͢Δ৔߹ ຊମίʔυɺ΋͘͠͸ଞͷςετ΁  ӨڹΛ༩͑ͳ͍ͨΊʹɺ 6TFS%FGBVMUTʹՃ͑ͨมߋΛऔΓফ͢

҉໧తͳೖग़ྗͷςετྫ ˙ 6TFS%FGBVMUTΛ௚઀৮Δͱ͕͜͜ਏ͍ ɾ༩͑ͨมߋΛফ͠๨ΕΔͱɺຊମ࣮ߦ࣌΍ଞͷςετʹӨڹ͢Δ ɾςετߦ͏ͱ΋Εͳ͘ ʮ6TFS%FGBVMUT΁ͷૢ࡞෭࡞༻ʯ͕ੜͯ͡͠·͏ ෭࡞༻ͳ͘ςετ͍ͨ͠ʂ

෭࡞༻ͳ͘ςετΛߦ͏ͨΊʹ ˙ ҉໧తͳೖग़ྗ େҬม਺ͳͲ େҬม਺ͳͲ doSomething(x) Ҿ਺ ໭Γ஋ ελϒͱ͍͏ख๏ Λ࢖͍·͢
εύΠͱ͍͏ख๏ Λ࢖͍·͢

҉໧తೖྗͷςετΛ ͢ΔͨΊʹελϒΛ࢖͏ ຊ୊ͦͷ̍

doSomething(x) Ҿ਺ େҬม਺ͳͲ ࣄલʹઃఆͨ͠ৼΔ෣͍Λ͢Δ  ِ෺ͷΦϒδΣΫτ ελϒ ໭Γ஋ ˞ࢲ͕͜Ε͔Βઆ໌͢ΔʮελϒʯͷৼΔ෣͍͸্هͷ΋ͷ ʹͳΓ·͢ ಉ໊ͰผͷఆٛΛࢦ͢͜ͱ΋͋ΔͨΊ
҉໧తೖྗͷςετΛ͢ΔͨΊʹελϒΛ࢖͏

҉໧తೖྗͷςετΛ͢ΔͨΊʹελϒΛ࢖͏ ˙ ཁ݅6TFS%FGBVMUT͔Βऔಘͨ͠஋ *OU Ҿ਺໭Γ஋ class Input { func
multiplication(int: Int) -> Int { let base = UserDefaults.standard.integer(forKey: “base") return base * int }

multiplication(int: Int) -> Int { let base = UserDefaults.standard.integer(forKey: “base") return base * int } େҬม਺͔Βऔಘ͍ͯ͠Δ

multiplication(int: Int) -> Int { let base = UserDefaults.standard.integer(forKey: “base") return base * int } େҬม਺͔Βऔಘ͍ͯ͠Δ ςετ࣌͸ِ෺ʹࠩ͠ସ͍͑ͨ

multiplication(int: Int) -> Int { let base = UserDefaults.standard.integer(forKey: “base") return base * int } େҬม਺͔Βऔಘ͍ͯ͠Δ ςετ࣌͸ِ෺ʹࠩ͠ସ͍͑ͨ ελϒΛ࢖͍͍ͨ

multiplication(int: Int) -> Int { let base = UserDefaults.standard.integer(forKey: “base") return base * int } ςετ࣌͸ِ෺ʹࠩ͠ସ͍͑ͨ ελϒΛ࢖͍͍ͨ ελϒΛ࢖͑Δঢ়ଶʹ͢Δʂ େҬม਺͔Βऔಘ͍ͯ͠Δ

ελϒΛ࢖͑Δঢ়ଶʹ͢Δ multiplication(int:) Ҿ਺ 6TFS%FGBVMUT ελϒ ໭Γ஋ 6TFS%FGBVMU͔Β௚઀औಘ͸ͤͣʹɺ  ৼΔ෣͍Λ੍ޚͰ͖ΔΦϒδΣΫτΛڬΉ

ελϒΛ࢖͑Δঢ়ଶʹ͢Δ ᶃ੍ޚ͍ͨ͠ৼΔ෣͍Λ1SPUPDPMʹ͢Δ protocol ReadableRepositoryContract { func read() -> Int }

ελϒΛ࢖͑Δঢ়ଶʹ͢Δ ᶄ1SPUPDPMʹ४ڌͨ͠ΫϥεΛ࡞੒͢Δ class ReadableRepository: ReadableRepositoryContract { func read() -> Int
{ return UserDefaults.standard.integer(forKey: "base") } }

ελϒΛ࢖͑Δঢ়ଶʹ͢Δ ᶅ҉໧తೖྗͷՕॴͰ͸1SPUPDPMΛར༻͢ΔΑ͏ʹมߋ͢Δ class Input { func multiplication(int: Int) -> Int
{ let base = UserDefaults.standard.integer(forKey: “base") return base * int } }

ελϒΛ࢖͑Δঢ়ଶʹ͢Δ class Input { private let repository: ReadableRepositoryContract func multiplication(int:
Int) -> Int { let base = UserDefaults.standard.integer(forKey: “base") return base * int } } ᶅ҉໧తೖྗͷՕॴͰ͸1SPUPDPMΛར༻͢ΔΑ͏ʹมߋ͢Δ

ελϒΛ࢖͑Δঢ়ଶʹ͢Δ class Input { private let repository: ReadableRepositoryContract init (repository:
ReadableRepositoryContract) { self.repository = repository } func multiplication(int: Int) -> Int { let base = UserDefaults.standard.integer(forKey: “base") return base * int } } ᶅ҉໧తೖྗͷՕॴͰ͸1SPUPDPMΛར༻͢ΔΑ͏ʹมߋ͢Δ

class Input { private let repository: ReadableRepositoryContract init (repository: ReadableRepositoryContract)
{ self.repository = repository } func multiplication(int: Int) -> Int { let base = self.repository.read() return base * int } } ελϒΛ࢖͑Δঢ়ଶʹ͢Δ ᶅ҉໧తೖྗͷՕॴͰ͸1SPUPDPMΛར༻͢ΔΑ͏ʹมߋ͢Δ

{ self.repository = repository } func multiplication(int: Int) -> Int { let base = self.repository.read() return base * int } } ελϒΛ࢖͑Δঢ়ଶʹ͢Δ ᶅ҉໧తೖྗͷՕॴͰ͸1SPUPDPMΛར༻͢ΔΑ͏ʹมߋ͢Δ ˙ ཁ݅6TFS%FGBVMUT͔Βऔಘͨ͠஋ *OU Ҿ਺໭Γ஋

{ self.repository = repository } func multiplication(int: Int) -> Int { let base = self.repository.read() return base * int } } ελϒΛ࢖͑Δঢ়ଶʹ͢Δ ᶅ҉໧తೖྗͷՕॴͰ͸1SPUPDPMΛར༻͢ΔΑ͏ʹมߋ͢Δ ˙ ཁ݅6TFS%FGBVMUT͔Βऔಘͨ͠஋ *OU Ҿ਺໭Γ஋ ˙ ཁ݅3FQPTJUPSZ͔Βऔಘͨ͠஋ *OU Ҿ਺໭Γ஋

ελϒΛ࢖͏४උ͸Ͱ͖ͨ

ελϒΛ࢖ͬͯςετΛॻ͘ ελϒΛ࢖͏४උ͸Ͱ͖ͨ

ελϒΛ࢖ͬͯςετΛॻ͘ class ReadableRepositoryStub: ReadableRepositoryContract { private let base: Int init(base:
Int) { self.base = base } func read() -> Int { return self.base } } 1SPUPDPMʹ४ڌͨ͠ελϒΛ࡞੒͢Δ

class ReadableRepositoryStub: ReadableRepositoryContract { private let base: Int init(base: Int)
{ self.base = base } func read() -> Int { return self.base } } ελϒΛ࢖ͬͯςετΛॻ͘ 1SPUPDPMʹ४ڌͨ͠ελϒΛ࡞੒͢Δ ʮِ෺ͷৼΔ෣͍ʯΛߦͳ͍ͬͯΔՕॴ

class InputTests: XCTestCase { func testMultiplication() { let base =
5 let int = 2 let expected = 10 } } ˙ ςετέʔε ɾظ଴͕ฦͬͯ͘Δ ελϒΛ࢖ͬͯςετΛॻ͘ ɾঢ়گCBTF JOUͷ࣌

5 let int = 2 let expected = 10 let repositoryStub = ReadableRepositoryStub(base: base) let input = Input(repository: repositoryStub) } } ɾঢ়گCBTF JOUͷ࣌ ˙ ςετέʔε ɾظ଴͕ฦͬͯ͘Δ ελϒΛ࢖ͬͯςετΛॻ͘ ελϒΛࠩ͠ࠐΉ

5 let int = 2 let expected = 10 let repositoryStub = ReadableRepositoryStub(base: base) let input = Input(repository: repositoryStub) let actual = input.multiplication(int: int) XCTAssertEqual(actual, expected) } } ɾঢ়گJOU CBTFͷ࣌ ˙ ςετέʔε ɾظ଴͕ฦͬͯ͘Δ ελϒΛ࢖ͬͯςετΛॻ͘ தͰελϒ͕࢖ΘΕ͍ͯΔ

ελϒ׬

҉໧తग़ྗͷςετΛ ͢ΔͨΊʹεύΠΛ࢖͏ ຊ୊ͦͷ̎

doSomething(x) Ҿ਺ ໭Γ஋ େҬม਺ͳͲ ِ෺ͷؔ਺΍ΦϒδΣΫτͰɺ  ݺͼग़͠΍ࣗ਎΁ͷมߋΛه࿥͢Δ εύΠ ҉໧తग़ྗͷςετΛ͢ΔͨΊʹεύΠΛ࢖͏

҉໧తग़ྗͷςετΛ͢ΔͨΊʹεύΠΛ࢖͏ ˙ ཁ݅Ҿ਺Ͱड͚औͬͨ஋Λ6TFS%FGBVMUTʹอଘ͢Δ class Output { func write(int: Int) {
UserDefaults.standard.set(int, forKey: "write") } }

class Output { func write(int: Int) { UserDefaults.standard.set(int, forKey: "write")
} } ҉໧తग़ྗͷςετΛ͢ΔͨΊʹεύΠΛ࢖͏ ˙ ཁ݅Ҿ਺Ͱड͚औͬͨ஋Λ6TFS%FGBVMUTʹอଘ͢Δ େҬม਺΁ه࿥͍ͯ͠Δ

} } ҉໧తग़ྗͷςετΛ͢ΔͨΊʹεύΠΛ࢖͏ ˙ ཁ݅Ҿ਺Ͱड͚औͬͨ஋Λ6TFS%FGBVMUTʹอଘ͢Δ େҬม਺΁ه࿥͍ͯ͠Δ ςετ࣌͸ผͷ৔ॴʹه࿥͍ͨ͠

} } ҉໧తग़ྗͷςετΛ͢ΔͨΊʹεύΠΛ࢖͏ ˙ ཁ݅Ҿ਺Ͱड͚औͬͨ஋Λ6TFS%FGBVMUTʹอଘ͢Δ େҬม਺΁ه࿥͍ͯ͠Δ ςετ࣌͸ผͷ৔ॴʹه࿥͍ͨ͠ εύΠΛ࢖͍͍ͨ

} } ҉໧తग़ྗͷςετΛ͢ΔͨΊʹεύΠΛ࢖͏ ˙ ཁ݅Ҿ਺Ͱड͚औͬͨ஋Λ6TFS%FGBVMUTʹอଘ͢Δ େҬม਺΁ه࿥͍ͯ͠Δ ςετ࣌͸ผͷ৔ॴʹه࿥͍ͨ͠ εύΠΛ࢖͍͍ͨ εύΠΛ࢖͑Δঢ়ଶʹ͢Δʂ

save(int:) Ҿ਺ 6TFS%FGBVMUT εύΠ εύΠΛ࢖͑Δঢ়ଶʹ͢Δ 6TFS%FGBVMU΁௚઀ه࿥͸ͤͣʹɺ  ݺͼग़͠΍มߋΛه࿥Ͱ͖ΔΦϒδΣΫτΛڬΉ

εύΠΛ࢖͑Δঢ়ଶʹ͢Δ ᶃه࿥͍ͨ͠ৼΔ෣͍Λ1SPUPDPMʹ͢Δ protocol WritableRepositoryContract { func write(int: Int) }

εύΠΛ࢖͑Δঢ়ଶʹ͢Δ ᶄ1SPUPDPMʹ४ڌͨ͠ΫϥεΛ࡞੒ class WritableRepository: WritableRepositoryContract { func write(int: Int) {
UserDefaults.standard.set(int, forKey: “write") } }

ᶅ҉໧తग़ྗͷՕॴͰ͸1SPUPDPMΛར༻͢ΔΑ͏ʹมߋ͢Δ εύΠΛ࢖͑Δঢ়ଶʹ͢Δ class Output { func write(int: Int) { UserDefaults.standard.set(int,
forKey: "write") } }

class Output { private let repository: WritableRepositoryContract func write(int: Int)
{ UserDefaults.standard.set(int, forKey: "write") } } εύΠΛ࢖͑Δঢ়ଶʹ͢Δ ᶅ҉໧తग़ྗͷՕॴͰ͸1SPUPDPMΛར༻͢ΔΑ͏ʹมߋ͢Δ

class Output { private let repository: WritableRepositoryContract init(repository: WritableRepositoryContract) {
self.repository = repository } func write(int: Int) { UserDefaults.standard.set(int, forKey: "write") } } εύΠΛ࢖͑Δঢ়ଶʹ͢Δ ᶅ҉໧తग़ྗͷՕॴͰ͸1SPUPDPMΛར༻͢ΔΑ͏ʹมߋ͢Δ

self.repository = repository } func write(int: Int) { self.repository.write(int: int) } } εύΠΛ࢖͑Δঢ়ଶʹ͢Δ ᶅ҉໧తग़ྗͷՕॴͰ͸1SPUPDPMΛར༻͢ΔΑ͏ʹมߋ͢Δ

self.repository = repository } func write(int: Int) { self.repository.write(int: int) } } εύΠΛ࢖͑Δঢ়ଶʹ͢Δ ᶅ҉໧తग़ྗͷՕॴͰ͸1SPUPDPMΛར༻͢ΔΑ͏ʹมߋ͢Δ ˙ ཁ݅Ҿ਺Ͱड͚औͬͨ஋Λ6TFS%FGBVMUTʹอଘ͢Δ

self.repository = repository } func write(int: Int) { self.repository.write(int: int) } } εύΠΛ࢖͑Δঢ়ଶʹ͢Δ ᶅ҉໧తग़ྗͷՕॴͰ͸1SPUPDPMΛར༻͢ΔΑ͏ʹมߋ͢Δ ˙ ཁ݅Ҿ਺Ͱड͚औͬͨ஋Λ6TFS%FGBVMUTʹอଘ͢Δ ˙ ཁ݅Ҿ਺Ͱड͚औͬͨ஋Λ3FQPTJUPSZʹ౉͢

εύΠΛ࢖͏४උ͸Ͱ͖ͨ

εύΠΛ࢖ͬͯςετΛॻ͘ εύΠΛ࢖͏४උ͸Ͱ͖ͨ

εύΠΛ࢖ͬͯςετΛॻ͘ 1SPUPDPMʹ४ڌͨ͠εύΠΛ࡞੒͢Δ class WritableRepositorySpy: WritableRepositoryContract { /// ϝιου͕ݺͼग़͞ΕͨࡍͷҾ਺ྻɻ private(set) var
callArguments: [Int] = [] func write(int: Int) { self.record(int) } private func record(_ args: Int) { self.callArguments += [args] } }

class WritableRepositorySpy: WritableRepositoryContract { /// ϝιου͕ݺͼग़͞ΕͨࡍͷҾ਺ྻɻ private(set) var callArguments: [Int]
= [] func write(int: Int) { self.record(int) } private func record(_ args: Int) { self.callArguments += [args] } } εύΠΛ࢖ͬͯςετΛॻ͘ ϓϩτίϧ४ڌ 1SPUPDPMʹ४ڌͨ͠εύΠΛ࡞੒͢Δ

class WritableRepositorySpy: WritableRepositoryContract { /// ϝιου͕ݺͼग़͞ΕͨࡍͷҾ਺ྻɻ private(set) var callArguments: [Int]
= [] func write(int: Int) { self.record(int) } private func record(_ args: Int) { self.callArguments += [args] } } εύΠΛ࢖ͬͯςετΛॻ͘ ݺͼग़͠Λه࿥͢Δ 1SPUPDPMʹ४ڌͨ͠εύΠΛ࡞੒͢Δ

εύΠΛ࢖ͬͯςετΛॻ͘ ɾঢ়گJOUͷ࣌ ˙ ςετέʔε ɾظ଴6TFS%FGBVMUT΁lz͕อଘ͞ΕΔ class OutputTests: XCTestCase { func
testWrite() { let int = 2 } }

testWrite() { let int = 2 let spy = WritableRepositorySpy() let output = Output(repository: spy)  } } εύΠΛࠩ͠ࠐΉ

testWrite() { let int = 2 let spy = WritableRepositorySpy() let output = Output(repository: spy)  output.write(int: int) XCTAssertEqual(int, spy.callArguments.first!) } } தͰεύΠ͕࢖ΘΕ͍ͯΔ

testWrite() { let int = 2 let spy = WritableRepositorySpy() let output = Output(repository: spy)  output.write(int: int) XCTAssertEqual(int, spy.callArguments.first!) } } εύΠʹه࿥͞Εͨ஋Λ֬ೝ͢Δ

εύΠ׬

·ͱΊ ˙ ҉໧తೖग़ྗ͕͋Δ৔߹ ɾೖྗ ɾِ෺ʹࠩ͠ସ͑ΒΕΔͱςετͷ४උָ͕ʹͳΔΑ ɾग़ྗ ɾʮ6TFS%FGBVMUTʹ΂ͬͨΓґଘʯͳΜͯ͜ͱ͕ແ͘ͳΔΑ ɾ1SPUPDPMΛ࢖ͬͯελϒ औಘ༻ͷِ෺ Λ
ɹࠩ͠ࠐΊΔΑ͏ʹ͠Α͏ ɾ1SPUPDPMΛ࢖ͬͯεύΠ ه࿥༻ͷِ෺ Λ ɹࠩ͠ࠐΊΔΑ͏ʹ͠Α͏ ˙ ϝϦοτ

&OKPZ5FTU%BZT

単体テストのハジメ

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