Property-based testing with SwiftCheck/PBT-with-SwiftCheck

Property-based testing with SwiftCheck

Transcript

1. Copyright (C) DeNA Co.,Ltd. All Rights Reserved. iOS Test Night #5 2017/07/26(Wed) 
 ࡉপ༞հ@DeNA 1SPQFSUZCBTFE
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   ⁃ ͱ͔޷͖Ͱ͢ ࣗݾ঺հ Copyright (C) DeNA Co.,Ltd. All Rights Reserved. 2
3. ࠓ೔ɺ࿩͢͜ͱ 3 Copyright (C) DeNA Co.,Ltd. All Rights Reserved.
4. 1SPQFSUZCBTFE
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   4XJGU$IFDL 4 Copyright (C) DeNA Co.,Ltd. All Rights Reserved.
5. ΞδΣϯμ 5 Copyright (C) DeNA Co.,Ltd. All Rights Reserved. • 1SPQFSUZCBTFE
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6. 1SPQFSUZCBTFE
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   ͱ͸ʁ 6 Copyright (C) DeNA Co.,Ltd. All Rights Reserved.
7. Property-based testing ͱ͸ʁ 7 Copyright (C) DeNA Co.,Ltd. All Rights Reserved. • ଟ਺ͳϥϯμϜ஋Λ'8ʹࣗಈੜ੒ͤ͞ɺ
   • ςετର৅ͷੑ࣭ʢ1SPQFSUZʣΛίʔυͰఆٛ͠ɺ
   • ͦͷੑ࣭͕ഁΒΕΔ஋͕ͳ͍͔ݕূ͢Δ
   • Ϣχοτςετख๏ͷͭ
   • ؔ਺ܕݴޠ)BTLFMMͷʮ2VJDL$IFDLʯ͕ݩ
8. 4XJGU$IFDL 8 Copyright (C) DeNA Co.,Ltd. All Rights Reserved.
9. 4XJGU$IFDL
   ͱ͸ʁ 9 Copyright (C) DeNA Co.,Ltd. All Rights Reserved. • 2VJDL$IFDL
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10. 10 Copyright (C) DeNA Co.,Ltd. All Rights Reserved. • 1SPQFSUZCBTFE
    UFTUJOH
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11. ۩ମྫͱͯ͠
    ଍͠ࢉͷςετΛߟ͑ͯΈΔ 11 Copyright (C) DeNA Co.,Ltd. All Rights Reserved.
12. 9$5FTU
    &YBNQMFCBTFE
    UFTUJOH 12 Copyright (C) DeNA Co.,Ltd. All Rights Reserved.
13. // ϓϩμΫτίʔυ
    func add(_ x: UInt, _ y: UInt) -> UInt { return x + y } // ςετίʔυ
    func test_add_by_assert() { XCTAssertEqual(add(1, 2), 3) } XCTest Ͱͷ଍͠ࢉͷςετ 13 Copyright (C) DeNA Co.,Ltd. All Rights Reserved. 1 + 2 ͷ݁Ռ͸ 3 Ͱ͋Δ͜ͱ • ҰൠతͳY6OJU͕ఏڙ͍ͯ͠Δํ๏
    • 2VJDLͳͲͷ#%%ͳ'8΋ຊ࣭తʹ͸ಉ͡
14. ਤઆ 14 Copyright (C) DeNA Co.,Ltd. All Rights Reserved. ̍ʴ̎ʹ̏ ೖྗ஋ ೖྗ஋ ظ଴஋ ςετର৅
15. ਤઆ 15 Copyright (C) DeNA Co.,Ltd. All Rights Reserved. ̍ʴ̎ʹ̏ ೖྗ஋ ೖྗ஋ ظ଴஋ ςετର৅ ೖྗ஋ͱظ଴஋͸ɺ
    ։ൃऀ͕໌ࣔతʹબͿඞཁ͕͋Δ
16. Ͳ͏΍ͬͯೖྗ஋ΛબͿʁ 16 Copyright (C) DeNA Co.,Ltd. All Rights Reserved.
17. ςετ༻ͷೖྗ஋ΛબͿٕज़ 17 Copyright (C) DeNA Co.,Ltd. All Rights Reserved. • ಉ஋෼ׂ๏
    • ڥք஋෼ੳ
    • ΫϥγϑΟέʔγϣϯπϦʔ
    • 1BJSXJTF๏
    • FUDʜ
18. ςετ༻ͷೖྗ஋ΛબͿٕज़ 18 Copyright (C) DeNA Co.,Ltd. All Rights Reserved. • ಉ஋෼ׂ๏
    • ڥք஋෼ੳ
    • ΫϥγϑΟέʔγϣϯπϦʔ
    • 1BJSXJTF๏
    • FUDʜ ͲΕ΋֬཰తʹόάͷى͖΍͍͢σʔ λΛ༧ଌͯ͠ɺಛఆ஋ͷΈͰςετ
19. 4XJGU$IFDL
    1SPQFSUZCBTFE
    UFTUJOH 19 Copyright (C) DeNA Co.,Ltd. All Rights Reserved.
20. ·ͣ଍͠ࢉͷੑ࣭Λߟ͑Δ 20 Copyright (C) DeNA Co.,Ltd. All Rights Reserved.
21. ଍͠ࢉͷੑ࣭ 21 Copyright (C) DeNA Co.,Ltd. All Rights Reserved. • ݁߹๏ଇΛຬͨ͢
    • Y
    
    Z
    
    Z
    
    Y
    • Λճ଍ͨ͠΋ͷͱɺΛճ଍ͨ͠΋ͷ͸౳͍͠
    • Y
    
    
    
    
    
    Y
    
    
    • ʢͪͳΈʹʣҾ͖ࢉ͸݁߹๏ଇΛຬͨ͞ͳ͍
    • Y
    
    Z
    㱠
    Z
    
    Y
    
22. ଍͠ࢉͷੑ࣭ 22 Copyright (C) DeNA Co.,Ltd. All Rights Reserved. • ݁߹๏ଇΛຬͨ͢
    • Y
    
    Z
    
    Z
    
    Y
    • Λճ଍ͨ͠΋ͷͱɺΛճ଍ͨ͠΋ͷ͸౳͍͠
    • Y
    
    
    
    
    
    Y
    
    
    • ʢͪͳΈʹʣҾ͖ࢉ͸݁߹ੑ͋Γ
    • Y
    
    Z
    㱠
    Z
    
    Y
    ͜ΕΒ͕ͲΜͳೖྗ஋ʹରͯ͠΋
    อͨΕΔ΂͖ੑ࣭Ͱ͋Δɺͱߟ͑Δ
23. 4XJGU$IFDLͰॻ͍ͯΈΔ 23 Copyright (C) DeNA Co.,Ltd. All Rights Reserved.
24. 4XJGU$IFDL
    Ͱͷ଍͠ࢉͷੑ࣭ςετ 24 Copyright (C) DeNA Co.,Ltd. All Rights Reserved. // ;ͭ͏ͷXCTestͱಉ͡Α͏ʹ಄ʹ`test`Λ͚ͭΔ func test_add_property() { // x + y == y + x property("଍͠ࢉ͸݁߹๏ଇΛຬͨ͢") <- forAll { (x: UInt, y: UInt) in return add(x, y) == add(y, x) } // x + 1 + 1 == x + 2 property("1Λ2ճ଍ͨ͠ͷͱɺ2Λ1ճ଍ͨ͠΋ͷ͸౳͍͠") <- forAll { (x: UInt) in return add(add(x, 1), 1) == add(x, 2) } }
25. 4XJGU$IFDL
    Ͱͷ଍͠ࢉͷੑ࣭ςετ 25 Copyright (C) DeNA Co.,Ltd. All Rights Reserved. func test_add_property() { // x + y == y + x property("଍͠ࢉ͸݁߹๏ଇΛຬͨ͢") <- forAll { (x: UInt, y: UInt) in return add(x, y) == add(y, x) } } ᶃੑ࣭ͷએݴ
26. 4XJGU$IFDL
    Ͱͷ଍͠ࢉͷੑ࣭ςετ 26 Copyright (C) DeNA Co.,Ltd. All Rights Reserved. func test_add_property() { // x + y == y + x property("଍͠ࢉ͸݁߹๏ଇΛຬͨ͢") <- forAll { (x: UInt, y: UInt) in return add(x, y) == add(y, x) } } ᶄ೚ҙͷೖྗ஋
27. 4XJGU$IFDL
    Ͱͷ଍͠ࢉͷੑ࣭ςετ 27 Copyright (C) DeNA Co.,Ltd. All Rights Reserved. func test_add_property() { // x + y == y + x property("଍͠ࢉ͸݁߹๏ଇΛຬͨ͢") <- forAll { (x: UInt, y: UInt) in return add(x, y) == add(y, x) } } ᶅશͯʹର͠
28. 4XJGU$IFDL
    Ͱͷ଍͠ࢉͷੑ࣭ςετ 28 Copyright (C) DeNA Co.,Ltd. All Rights Reserved. func test_add_property() { // x + y == y + x property("଍͠ࢉ͸݁߹๏ଇΛຬͨ͢") <- forAll { (x: UInt, y: UInt) in return add(x, y) == add(y, x) } } ᶆ͜ͷ͕ࣜ੒Γཱͭ
29. 4XJGU$IFDL
    Ͱͷ଍͠ࢉͷੑ࣭ςετ 29 Copyright (C) DeNA Co.,Ltd. All Rights Reserved. func test_add_property() { // x + y == y + x property("଍͠ࢉ͸݁߹๏ଇΛຬͨ͢") <- forAll { (x: UInt, y: UInt) in return add(x, y) == add(y, x) } } ᶃੑ࣭ͷએݴ ᶄ೚ҙͷೖྗ஋ ᶅશͯʹର͠ ᶆ͜ͷ͕ࣜ੒Γཱͭ
30. ͜ΕΛ࣮ߦ͢Δͱʁ 30 Copyright (C) DeNA Co.,Ltd. All Rights Reserved.
31. Test Case '-[SwiftCheckSampleTests.SwiftCheckSampleTests test_add_property]' started. *** Passed 100 tests . *** Passed 100 tests . Test Case '-[SwiftCheckSampleTests.SwiftCheckSampleTests test_add_property]' passed (0.009 seconds). 4XJGU$IFDLͰͷςετ͕੒ޭ 31 Copyright (C) DeNA Co.,Ltd. All Rights Reserved. ίϯιʔϧ
    1BTTFE
    
    UFTUT ݸ΋ͷϥϯμϜ஋Ͱςετ͕͞Ε͍ͯΔʂ
32. ۩ମతʹͲΜͳ஋͕
    બ͹Ε͍ͯΔͷ͔ʁ 32 Copyright (C) DeNA Co.,Ltd. All Rights Reserved.
33. ۩ମతʹબ͹Ε͍ͯͨ஋ 33 Copyright (C) DeNA Co.,Ltd. All Rights Reserved. Test Case '-[SwiftCheckSampleTests.SwiftCheckSampleTests test_add_property]' started. x: 0, y: 0 x: 1, y: 1 x: 0, y: 2 x: 3, y: 3 x: 0, y: 0 x: 1, y: 1 x: 0, y: 6 x: 4, y: 1 … x: 26, y: 19 x: 34, y: 51 x: 40, y: 18 x: 10, y: 13 x: 49, y: 22 x: 9, y: 14 x: 31, y: 65 x: 45, y: 15 x: 30, y: 32 x: 46, y: 54 x: 65, y: 34 x: 57, y: 41 … x: 58, y: 17 x: 67, y: 17 x: 41, y: 93 x: 21, y: 17 *** Passed 100 tests ϥϯμϜ͚ͩΕͲɺ
    খ͞Ίͷ஋͔Βςετ͞Ε͍ͯΔ
34. ͱ͜ΖͰࣦഊ͢Δͱʁ 34 Copyright (C) DeNA Co.,Ltd. All Rights Reserved.
35. *** Failed! Proposition: x + 1 + 1 == x + 2 Falsifiable (after 3 tests and 2 shrinks): 1 *** Passed 2 tests 4XJGU$IFDLͰͷςετ͕੒ޭ 35 Copyright (C) DeNA Co.,Ltd. All Rights Reserved. ίϯιʔϧ ஋͕ʮʯͷέʔεͰɺ
    ςετ͕ύε͠ͳ͔ͬͨ͜ͱ͕ใࠂ͞Εͨ
36. ࣮ࡍʹʮʯͷέʔεͰ
    ࢼͯ͠ΈΔͱɾɾɾ 36 Copyright (C) DeNA Co.,Ltd. All Rights Reserved.
37. 9$5"TTFSU&RVBMͰݕূ 37 Copyright (C) DeNA Co.,Ltd. All Rights Reserved. ͔֬ʹςετ͕ࣦഊͨ͠ʂ func add(_ x: UInt, _ y: UInt) -> UInt { return x * y } ݪҼ͸ֻ͚ࢉʹͳ͍ͬͯͨҝ
38. 38 Copyright (C) DeNA Co.,Ltd. All Rights Reserved. • 1SPQFSUZCBTFE
    UFTUJOH
    ͱ͸ʁ
    • 4XJGU$IFDL
    ͱ͸ʁ
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    • ࣮ફతͳϢʔεέʔε
    • ·ͱΊ
39. ഑ྻͷ൓స
    "SSBZSFWFSTFE 39 Copyright (C) DeNA Co.,Ltd. All Rights Reserved.
40. ൓స SFWFSTF ͷੑ࣭ͱ͸ʁ 40 Copyright (C) DeNA Co.,Ltd. All Rights Reserved.
41. ഑ྻͷ൓సͷੑ࣭ͱ͸ʁ 41 Copyright (C) DeNA Co.,Ltd. All Rights Reserved.
    ˣ൓స SFWFSTF
    ˣ൓స SFWFSTF ճ൓సͤ͞Δͱݩʹ໭Δʂ
42. 4XJGU$IFDLͰॻ͍ͯΈΔ 42 Copyright (C) DeNA Co.,Ltd. All Rights Reserved.
43. func test_reversed() { property("഑ྻͷ൓సͷ൓స͸ݩͷ഑ྻͱಉ͡") <- forAll { (xs: ArrayOf<Int>) in let ys = xs.getArray return ys.reversed().reversed() == ys } } 4XJGU$IFDL
    Ͱ഑ྻͷ൓సͷςετ 43 Copyright (C) DeNA Co.,Ltd. All Rights Reserved. YT
    <5>
    ͱදݱͰ͖ͳ͍ͷ͸4XJGUͷ੍ݶɻ
    ୅ΘΓʹ"SSBZ0G5ͱ͍͏ϥούʔΛࢦఆ͠ɺ
    HFU"SSBZͰத਎ΛऔΓग़͠ɻ "SSBZ0G*OU
44. ͜͜·Ͱͷ·ͱΊ 44 Copyright (C) DeNA Co.,Ltd. All Rights Reserved.
45. ͜͜·Ͱͷ·ͱΊ 45 Copyright (C) DeNA Co.,Ltd. All Rights Reserved. • 1SPQFSUZCBTFE
    UFTUJOH
    • ςετͱͯ͠ੑ࣭ʢQSPQFSUZʣΛఆٛ
    • '8͕܁Γฦ͠ϥϯμϜ஋ͰςετΛ࣮ߦ
    • 4XJGU$IFDL
    • 9$5FTUͱ૊Έ߹Θͤͯ࢖͑Δ
    • ࣦഊͨ͠৔߹ɺͦͷ஋Λใࠂͯ͘͠ΕΔ
    • ͦͷ஋͸Ͱ͖Δ͚ͩখ͍͞஋͕બ͹Ε͍ͯΔ
46. 46 Copyright (C) DeNA Co.,Ltd. All Rights Reserved. • 1SPQFSUZCBTFE
    UFTUJOH
    ͱ͸ʁ
    • 4XJGU$IFDL
    ͱ͸ʁ
    • ۩ମྫͰݟΔ
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    • ·ͱΊ
47. 1SPQFSUZCBTFE
    UFTUJOH
    Ͱͷ༻ޠ 47 Copyright (C) DeNA Co.,Ltd. All Rights Reserved.
48. "SCJUSBSZ 48 Copyright (C) DeNA Co.,Ltd. All Rights Reserved.
49. Arbitrary 49 Copyright (C) DeNA Co.,Ltd. All Rights Reserved. • ʮ೚ҙͷʯͱ͍ͬͨҙຯ
    • 4XJGU$IFDLͰ͸ϓϩτίϧͱͯ͠ఆٛ
    • ಛఆͷܕͷϥϯμϜ஋Λੜ੒͢Δ໾ׂ
    • 4XJGUඪ४ͷܕʹ͸σϑΥϧτ࣮૷͕ఏڙ͞ΕΔ
    • ͜Εʹ४ڌ͢Δ͜ͱͰϥϯμϜ஋͕ੜ੒Ͱ͖ΔΑ͏ʹ public protocol Arbitrary { public static var arbitrary: SwiftCheck.Gen<Self> { get } public static func shrink(_: Self) -> [Self] }
50. 4ISJOLJOH 50 Copyright (C) DeNA Co.,Ltd. All Rights Reserved.
51. Shrinking 51 Copyright (C) DeNA Co.,Ltd. All Rights Reserved. • ʮऩॖ͢Δʯͱ͍ͬͨҙຯ
    • ಉ͘͡"SCJUSBSZϓϩτίϧʹఆٛʢPQUJPOBMʣ
    • ΑΓখ͞ͳ஋ʹ͢Δ໾ׂ
    • ͜ΕʹΑΓࣦഊͨ͠ςετσʔλʹ͍ͭͯɺ
 ΑΓখ͞ͳࣦഊέʔεΛબग़͢Δ࢓૊Έ Int.shrink(10) // => [0, 1, 2, 5] String.shrink(“app") // => ["p", "pp", ... ,"apa", "apb"]
52. Shrinking 52 Copyright (C) DeNA Co.,Ltd. All Rights Reserved. • ʢࣦഊʣ
 ˣTISJOL
    • ʢࣦഊʣ
 ˣTISJOL
    • ʢࣦഊʣ⾣ɹ͜ΕΛʢ࠷খͷʣࣦഊྫͱͯ͠ใࠂ
 ˣTISJOL
    • ʢ੒ޭʣ
53. 53 Copyright (C) DeNA Co.,Ltd. All Rights Reserved. • 1SPQFSUZCBTFE
    UFTUJOH
    ͱ͸ʁ
    • 4XJGU$IFDL
    ͱ͸ʁ
    • ۩ମྫͰݟΔ
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    ഑ྻͷ൓స
    • ༻ޠ
    • ࣮ફతͳϢʔεέʔε
    • ·ͱΊ
54. 1SPQFSUZCBTFE
    UFTUJOH
    ͕༗ޮͳέʔε 54 Copyright (C) DeNA Co.,Ltd. All Rights Reserved.
55. Property-based testing ͕༗ޮͳέʔε 55 Copyright (C) DeNA Co.,Ltd. All Rights Reserved. • ᶃ
    &ODPEF
    
    %FDPEF
    • ᶄ
    ஗͘໌֬ͳΞϧΰϦζϜ
    WT
    ߴ଎ͳΞϧΰϦζϜ
    • ᶅ
    ϥϯμϜੑʹج͍ͮͨΞϧΰϦζϜ
56. ᶃ
    &ODPEF
    
    %FDPEF 56 Copyright (C) DeNA Co.,Ltd. All Rights Reserved.
57. Encode / Decode ͷϢχοτςετ 57 Copyright (C) DeNA Co.,Ltd. All Rights Reserved. • ΘΓͱେม
    • ϓϩύςΟ͕ଟ͍ͱॻ͘ͷେม
    • ಉ͡ೖྗ஋Λ࢖͏ͱೖΕସ͑Λݕग़Ͱ͖ͳ͍
    • ςετΛॻ͘࿑ྗʹݟ߹͍ͬͯΔ͔ʁ
    • ϦεΫ͕ߴ͍
    • Ұݟਖ਼͘͠ಈ͍͍ͯΔΑ͏ʹΈ͑Δ
    • ͚ΕͲɺҰ෦ͷ߲໨͚͚͍ͩܽͯͨΓ
58. Encode / Decode ͷੑ࣭ 58 Copyright (C) DeNA Co.,Ltd. All Rights Reserved. • &ODPEF
    
    %FDPEF
    ͨ͠΋ͷ͸ݩͱಉ͡
    • EFDPEF FODPEF PCK
    
    PCK
59. Dogߏ଄ମ 59 Copyright (C) DeNA Co.,Ltd. All Rights Reserved. public struct Dog: Equatable { let name: String let age: Int func encode() -> [String: String] { return [ "name": name, "age": "\(age)", ] } static func decode(_ encoded: [String: String]) -> Dog? { guard let name = encoded["name"], let age = (encoded["age"].flatMap{ Int($0) }) else { return nil } return Dog(name: name, age: age) } } public func == (a: Dog, b: Dog) -> Bool { return a.name == b.name && a.age == b.age }
60. Dog Λ Arbiratyϓϩτίϧʹ४ڌͤ͞Δ 60 Copyright (C) DeNA Co.,Ltd. All Rights Reserved. extension Dog: Arbitrary { public static var arbitrary: SwiftCheck.Gen<Dog> { return Gen<(String, Int)> .zip(String.arbitrary, Int.arbitrary) .map(Dog.init) } } ࠓճ͸TISJOLͷ࣮૷͸ׂѪ
    ʢͳͯ͘΋ಈ͖͸͢Δʣ
61. SwiftCheckͰͷςετίʔυ 61 Copyright (C) DeNA Co.,Ltd. All Rights Reserved. func testDogEncodeDecode() { property(“DogΛencodeͯ͠decodeͨ͠΋ͷ͸ɺݩͱಉ͡") <- forAll { (dog: Dog) in guard let decoded = Dog.decode(dog.encode()) else { return false } return dog == decoded } } "SCJUSBSZʹ४ڌͨ͠ͷͰɺ
    ϥϯμϜ஋͕ੜ੒Ͱ͖ΔΑ͏ʹͳͬͨ
62. ༷ʑͳσʔλͰςετ͞Ε͍ͯΔ 62 Copyright (C) DeNA Co.,Ltd. All Rights Reserved. Dog(name: "", age: 0) Dog(name: "O", age: 1) Dog(name: "d", age: 1) Dog(name: "ÇÆØ", age: 3) Dog(name: "!\\-", age: -4) Dog(name: "0S=ä", age: 3) Dog(name: "¡¨sóø", age: 1) Dog(name: "Ü+_<M", age: 4) Dog(name: "fín«ÄqÙv", age: -5) Dog(name: "ÁZõXü:¼¢", age: -4) Dog(name: "Ͼâñ. øýí", age: -9) Dog(name: "ùÝofNÁ&S", age: 9) Dog(name: " aÞäÈyÚ&Á", age: -5) Dog(name: "_¯¼Ì6<ÙRçv", age: 3) Dog(name: "êð©[ý#ùTó}°Õ|É", age: 7) Dog(name: "KVGH<ø«zE7\'", age: 12)
63. ᶄ
    ஗͘໌֬ͳΞϧΰϦζϜ
    WT
    ߴ଎ͳΞϧΰϦζϜ 63 Copyright (C) DeNA Co.,Ltd. All Rights Reserved.
64. ஗͘໌֬ͳΞϧΰϦζϜ vs ߴ଎ͳΞϧΰϦζϜ 64 Copyright (C) DeNA Co.,Ltd. All Rights Reserved. • ΞϧΰϦζϜ
    • ໌֬ͳॻ͖ํΛ͢Δͱʢ͍͍ͩͨʣ஗͍
    • ߴ଎ʹ͢Δͱʢ͍͍ͩͨʣίʔυ͕ෳࡶʹͳΔ
    • ςετͷ೉͠͞
    • +BWBͷ4%,ʹؚ·ΕΔೋ෼୳ࡧ͸ɺ
 ೥ؒ΋όάʹؾ͔ͮΕͳ͔ͬͨ
65. ஗͘໌֬ͳΞϧΰϦζϜ vs ߴ଎ͳΞϧΰϦζϜ 65 Copyright (C) DeNA Co.,Ltd. All Rights Reserved. • ੑ࣭Λߟ͑Δ
    • ೖྗ஋͕ಉ͡Ͱ͋Ε͹ɺ྆ऀͷ݁Ռ͸ৗʹಉ͡
    
66. ֊৐ΛٻΊΔίʔυ 66 Copyright (C) DeNA Co.,Ltd. All Rights Reserved. // ֊৐Λ࠶ؼͰٻΊΔ func fact(_ n: Int) -> Int { if n == 1 { return 1 } return n * fact(n - 1) } // ֊৐ΛϧʔϓͰٻΊΔ func factFast(_ n: Int) -> Int { var r = n var i = n - 1 while i > 1 { r *= i i = i - 1 } return r } ࠶ؼ൛͸͍͕ٙͳ͍͘Β͍ʹ໌֬ɻ͚ΕͲίʔϧ ελοΫͷ෼ɺύϑΥʔϚϯε͸ѱ͍
67. SwiftCheckͰͷςετίʔυ 67 Copyright (C) DeNA Co.,Ltd. All Rights Reserved. func test_fact() { // 1ʙ20ͷ஋ΛબͿʢେ͖͗͢ΔͱΤϥʔʹͳΔͨΊʣ let gen: Gen<Int> = Gen<Int>.choose((1, 20)) property("fact()ͱfactFast()͸ৗʹಉ݁͡ՌΛฦ͢͜ͱ") <- forAll(gen) { (n: Int) in return fact(n) == factFast(n) } } ໌֬ͳΞϧΰϦζϜͷ݁ՌͱҰக͍ͯ͠Ε͹ɺߴ ଎ͳΞϧΰϦζϜ΋ਖ਼͘͠ػೳ͍ͯ͠Δͱߟ͑Β ΕΔ DIPPTFͰ஋ͷൣғΛ੍ݶ
68. ᶅ
    ϥϯμϜੑʹج͍ͮͨ
    ΞϧΰϦζϜ 68 Copyright (C) DeNA Co.,Ltd. All Rights Reserved.
69. ϥϯμϜੑʹج͍ͮͨΞϧΰϦζϜ 69 Copyright (C) DeNA Co.,Ltd. All Rights Reserved. • έʔε
    • μϯδϣϯϚοϓͷੜ੒
    • μΠεϩʔϧ
    • ੑ࣭Λߟ͑Δ
    • Ϛοϓ͸ඞͣΰʔϧʹͭͳ͕͍ͬͯΔ͜ͱ
    • Ϛοϓʹ౸ୡͰ͖ͳ͍෦԰͕ͳ͍͜ͱ
    • े෼ʹۉ౳ͳϥϯμϜੑ͕ಘΒΕΔ͜ͱ
70. ࠓ೔ͷ·ͱΊ 70 Copyright (C) DeNA Co.,Ltd. All Rights Reserved.
71. ·ͱΊ 71 Copyright (C) DeNA Co.,Ltd. All Rights Reserved. • 1SPQFSUZCBTFE
    UFTUJOH
    • ੑ࣭ʢQSPQFSUZʣʹண໨ͨ͠Ϣχοτςετख๏
    • ଟ਺ͳϥϯμϜ஋Ͱςετ͞ΕΔ
    • 4XJGU$IFDL
    Ͱ
    9$5FTU
    ͱ૊Έ߹Θͤͯ࢖͑Δ
    • ࢖͍Ͳ͜Ζ
    • ޻෉࣍ୈͰ͍Ζ͍Ζ͋Γͦ͏
    • &YBNQMFCBTFE
    UFTUJOH
    ͱ஥ྑ͘
72. &OKPZ
    UIF
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     72 Copyright (C) DeNA Co.,Ltd. All Rights Reserved.