UnitTest Anti-Pattern

こんなUnitTest はイヤだ
~ 対策を添えて ~

Transcript

1. UnitTest Anti-Pattern
   2018/01/30 BPStudy#125
   Shoma Suzuki
   

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2. About Me
   • Software Engineer in Test at Mercari
   • github/twitter -> shoma
   • ։ൃ/ςετ؀ڥΛ੔උͨ͠Γ
   • CI ઃఆͨ͠Γ
   • ςετॻ͍ͨΓ
   • build Λ௚ͨ͠Γ
   • ٕज़తෛ࠴ͱ޲͖߹ͬͨΓ
   

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3. For Disclaimer
   • xUnit Test Patterns

   xunitpatterns.com
   • Unit testing Anti-patterns catalogue
   • stackoverflow.com/questions/333682/unit-testing-anti-
   patterns-catalogue
   • [࿨༁] joker1007.hatenablog.com/entry/20130709/
   1373365053
   • TddAntiPatterns

   www.hyuki.com/yukiwiki/wiki.cgi?TddAntiPatterns

   (ݪจ 404 NotFound)

   

   ʹ͍͍ͩͨॻ͍ͯ͋Γ·͢

   

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4. ͜ΜͳUnitTest ͸ΠϠͩ
   ~ ରࡦΛఴ͑ͯ ~
   

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5. 1. Assertion ͕ແ͍
   @Test

   public testSomething() {
   arrangeCondition();
   sut.theMethod();

   }
   

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6. 1. Assertion ͕ແ͍
   • [ݪҼ] ྫ֎͕ग़ͳ͚Ε͹͍͍΍/ಈ͔͚ͩ͢Ͱςετͨͭ͠
   ΋Γ
   • [ରࡦ] PMD JUnitTestsShouldIncludeAssert

   pmd.sourceforge.net/pmd-4.3.0/rules/
   junit.html#JUnitTestsShouldIncludeAssert
   • [ରࡦ] phpunit —report-useless-tests

   phpunit.de/manual/current/en/risky-tests.html
   • [ରࡦ] Test ͷଥ౰ੑΛݕূ͢Δ Mutation Test
   

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7. 2. ։ൃऀͷखݩ͚ͩͰಈ͘
   def test_config_exists():
   assert os.path.isfile(‘/Users/shoma/.gitconfig’)
   

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8. 2. ։ൃऀͷखݩ͚ͩͰಈ͘
   • ιʔείʔυ؅ཧ֎ͷϑΝΠϧ͸஫ҙ
   • /usr/bin ͱ͔΋ո͍͠
   • ؀ڥηοτΞοϓͷ೉қ౓্͕͕Δ
   • 127.0.0.1/localhost ΋஫ҙ͕ඞཁ
   • [ରࡦ] ؀ڥʹԠͯ͡มΘΔ΋ͷ͸؀ڥม਺Λ࢖͏
   • [ରࡦ] ηοτΞοϓ΋ؚΊ࣮ͨߦํ๏ͷ౷ҰԽ
   • [ରࡦ] ૣΊͷ CI
   • [ରࡦ] ։ൃ/ຊ൪Ұக 12factor.net/ja/dev-prod-parity
   

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9. 3. ςετ͍ͯ͠Δͷ͸Mockͩ
   class TheService {
   public Long calculate(Long a, Long b) {

   return innerService.calculate(a, b);
   }
   }

   @Test

   void testCalulate() {

   InnerService service = mock(InnerService.class):

   when(service.calculate(19L, 21L)).thenReturn(42L);

   // ུ

   Long res = theService.calculate(19L, 21L);

   assertEquals(LongValueOf(42L), res);
   }
   

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10. 3. ςετ͍ͯ͠Δͷ͸Mockͩ
    • [ݪҼ] Mock Λ࢖͍͗ͯ͢͠·͏
    • [ରࡦ] CodeCoverageϨϙʔτΛΈΑ͏
    • [ରࡦ] Mutation Test (લड़)
    

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11. 4. ඪ४ػೳͷςετ
    • Bug͕͋ΔͳΒ΍͓͍ͬͯͯ΋Α͍
    • ਖ਼نදݱͩͱ΍Γ͕ͪ
    • ʮTDD ͸։ൃதͷෆ҆Λίϯτʔϧ͢Δํ๏ͩʯ
    • ڍಈͷཧղ͸ਂ·Δ
    • [ݪҼ] ϥΠϒϥϦʹςετ͕ແ͔ͬͨ

    ˠ OSS ߩݙνϟϯε
    • [ରࡦ] ͋ͳͨͷίʔυΛςετ͠Α͏
    

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12. 5. ಈ͔͢ͱ՝ۚ͞ΕΔ
    • [ݪҼ] Ϋϥ΢υαʔϏεΛ࢖͍ͬͯΔ
    • [ݪҼ] Credential ͷѻ͍͕͋΍͍͠…
    • [ରࡦ] SDK ʹ Stub/Fake/Simulator ͕͋Δ͔
    ֬ೝ͠Α͏
    • [ରࡦ] ͜͜͸ Mock Խ
    

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13. 6. ͱ͖Ͳ͖ࣦഊ͢Δ
    • ೰ΜͰ·͢
    • [ରࡦ] Vefiry-Act-Vefiry
    • arrange લͷࣄલ৚͕݅๬Ήঢ়ଶͰ͋Δ͔֬ೝ͢Δ

    testautomationpatterns.wikispaces.com/VERIFY-ACT-VERIFY
    • [ରࡦ] ෆ҆ఆͳςετΛmark ͓ͯ͘͠

    github.com/nodejs/node/wiki/Flaky-tests
    • [ରࡦ] TestSize Λنఆͯ͠UnitTest ͱͯ͠΍ΔൣғΛܾΊΔ
    testing.googleblog.com/2010/12/test-sizes.html
    

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14. Happy Unit Testing!
    

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