Score the Tendulkar Test Coverage

Simple coding principles and design patterns you can follow to make your code testable and achieve organic and high test coverage

Transcript

1. Score
   
   
   the
   
   
   Tendulkar
   
   
   Test Coverage
   @GopalAkshintala
   

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2. Gopal S Akshintala
   
   
   Engineering Lead, Salesforce
   Community
   Day 2022
   September 10th, 2022
   
   
   T-Hub, Hyderabad
   @GopalAkshintala
   overfullstack.ga
   

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3. Sachin Tendulkar
   
   
   holds the record for
   
   
   highest number of dismissals
   
   
   in the 90s
   
   
   (28 times)🏏
   

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4. @GopalAkshintala
   

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5. Why
   
   
   Unit Test ?
   
   
   🧪
   @GopalAkshintala
   

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6. Why
   
   
   Unit Test?
   @GopalAkshintala
   Find Bugs
   Statement Coverage
   Behaviour documentation in form
   of code
   Strive for behaviour coverage
   NOT Statement coverage
   

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7. What makes Unit Testing
   
   
   Di
   ffi
   cult? 😓
   @GopalAkshintala
   Code Smells
   void methods
   static methods that are not static
   
   
   Bad Design
   Legacy Code interactions
   

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8. We have the Hammer!
   OOps!
   @GopalAkshintala
   

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9. The Unstoppable Hammer!
   OOps!
   @GopalAkshintala
   Suppress
   this and super constructor
   static init blocks
   Stub
   private methods
   static methods
   final methods
   Constructors
   Mock final classes
   

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10. The PowerMock Rocky!
    @GopalAkshintala
    OOps!
    100%
    

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11. The Dark Powers 👹
    Synthetic coverage is dangerous
    PowerMock is a new framework to
    learn
    Involves a lot of Setup and
    trail-and-error to get it right
    Tests written with PowerMock
    are brittle and difficult to
    Maintain
    It’s not Transparent
    OOps!
    @GopalAkshintala
    

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12. @GopalAkshintala
    

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13. PowerMock
    
    
    is a 💊
    
    
    Painkiller
    @GopalAkshintala
    

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14. But! Why is
    
    
    PowerMock
    
    
    Invasive?
    @GopalAkshintala
    

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15. @GopalAkshintala
    powermock.github.io
    

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16. PowerMock Compatibility
    Incompatible with JUnit 5
    JUnit 5 was release 5 years ago
    Incompatible with Latest Mockito
    Latest Mockito: 4.20
    Compatible version: 3.12
    Not fully compatible with Java 11
    OOps!
    @GopalAkshintala
    

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17. But do I need Unit Tests at all?
    
    
    Can’t I get Coverage with
    
    
    Integration Tests!?
    
    
    🤷
    @GopalAkshintala
    

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18. @GopalAkshintala
    ITests Vs UTests
    

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19. @GopalAkshintala
    Use-Case
    
    
    Diagram
    

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20. @GopalAkshintala
    ITests
    
    
    Vs
    
    
    UTests
    Use-case: How customer uses
    ITests should test Features
    Use-cases : Features : Components
    1
    Feature: Reflects software Functionality
    UTests should test Component Behaviour
    N N
    

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21. @GopalAkshintala
    ITests
    
    
    Vs
    
    
    UTests
    Traceability - How well a given
    test can precisely trace/pinpoint
    the cause of failure when it fails
    Productivity - Writing, Executing
    and Maintaining effort
    

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22. The Redemption
    
    
    🍕 🥗
    @GopalAkshintala
    

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23. @GopalAkshintala
    Code Smells
    
    
    🐽
    

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24. @GopalAkshintala
    Code Smells 🐽
    Avoid
    void
    Methods
    

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25. @GopalAkshintala
    Code
    Smells
    
    
    🐽
    Are static methods
    
    
    bad
    
    
    for Unit testing?
    

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26. @GopalAkshintala
    Pure Vs Impure
    Pure
    
    
    Logic
    Impure
    
    
    Side-Effects
    REST I/O
    
    
    DB I/O
    
    
    Events
    • Data-in
    

    Data-out
    
    
    • Referentially
    Transparent
    

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27. @GopalAkshintala
    Impure
    static void add(int a, int b) {
    
    
    System.out.println(a + b);
    
    
    }
    

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28. @GopalAkshintala
    Pure
    static int add(int a, int b) {
    
    
    return a + b;
    
    
    }
    

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29. @GopalAkshintala
    Impure Pure
    static void add(int a, int b,
    
    
    Consumer consumer) {
    
    
    consumer.accept(a + b);
    
    
    }
    
    
    / /
    Function call in Prod
    
    
    add(1, 2, System.out
    ::
    println);
    
    
    / /
    Function call in Test
    
    
    add(1, 2, result
    ->
    assertEquals(3, result));
    

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30. @GopalAkshintala
    Bad Design
    

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31. @GopalAkshintala
    Bad Design
    OOP
    P
    💩
    

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32. @GopalAkshintala
    👨💼
    🙉
    Domain
    
    
    Logic
    DB
    
    
    layer
    Prod
    Test
    

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33. @GopalAkshintala
    Design
    for Tests
    A Unit Test is the
    First client
    for your
    Component
    

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34. @GopalAkshintala
    Test in
    Isolation
    Mock
    Dependencies
    NOT
    Statements
    

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35. @GopalAkshintala
    Test in
    Isolation
    Inject
    your
    Dependencies
    💉
    

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36. @GopalAkshintala
    Legacy
    
    
    Dependencies
    🗿
    🗿
    

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37. @GopalAkshintala
    Legacy
    Dependencies
    If you interact
    with a

    Legacy component,
    Your component
    Instantly turns Legacy!
    

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38. @GopalAkshintala
    Legacy
    Dependencies
    If you “Directly” interact
    with a

    Legacy component,
    Your component
    Instantly turns Legacy!
    

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39. @GopalAkshintala
    Ports & Adapters
    Domain
    Adapters
    

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40. @GopalAkshintala
    👨💼
    🙉
    Domain
    
    
    Logic
    DB
    
    
    layer
    Prod
    Test
    

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41. @GopalAkshintala
    Port
    👨💼
    🐵
    Isolated
    
    
    Domain
    
    
    Logic
    DB
    
    
    layer
    Prod Adapter
    Fake Adapter
    Prod
    Test
    

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42. @GopalAkshintala
    Black box Unit Testing
    Unit Test
    !
    =
    Test Internals
    
    
    Unit Test
    ==
    E2E test for the Component
    

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43. @GopalAkshintala
    Anti-Patterns (digitaltapestry.net)
    https://confluence.internal.salesforce.com/display/TESTSFDC/
    Unit+Testing+Best+Practices
    https://confluence.internal.salesforce.com/display/TESTSFDC/
    Unit+Test+Recipes%3A+How+to+Write+High-Quality+Tests
    Explanation how proxy based Mock Frameworks work
    Write tests. Not too many. Mostly integration. (kentcdodds.com)
    Testing of Microservices - Spotify Engineering : Spotify Engineering
    (atspotify.com)
    On the Diverse And Fantastical Shapes of Testing (martinfowler.com)
    ongoing by Tim Bray · Testing in the Twenties (tbray.org)
    Resources
    

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44. No one gives you Change,
    you need to bring Change
    - Ramulu, Bus conductor
    #dadJoke
    

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45. @GopalAkshintala
    github.com/overfullstack/sttc-demo
    { }
    speakerdeck.com/gopalakshintala/
    score-the-tendulkar-test-coverage
    

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46. @GopalAkshintala
    🐵
    

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