Compiler Based Testing

Transcript

1. @xgouchet
   Compiler based
   Testing
   CodeMobile UK 2019 - Chester
   

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2. @xgouchet
   About me…
   Xavier F. Gouchet
   Android developer since the Cupcake years
   Lead Android Engineer at WorkWell
   @xgouchet on every social network you can
   think of…
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3. @xgouchet
   Testing is Hard
   Let’s let the compiler do most of the hard
   work for us
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4. @xgouchet
   Kotlin / Swift
   ▧ Statically Typed
   ▧ Strong Typed
   ▧ Type Safe
   ▧ Type Inference
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5. @xgouchet
   Basic use case — JSON
   {
   "id" : 481516,
   "title" : "Lorem ipsum dolor sit amet…",
   "picture" : "https://cloudhost.com/5162342",
   "created": 1553631328
   }
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6. @xgouchet
   Basic use case — App Model
   data class Event(
   val id: Int,
   val title: String,
   val picture: String,
   val created: Int
   }
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7. @xgouchet
   Primitive Aversion
   Primitives are lightweight…
   but lack context
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8. @xgouchet
   Use existing types
   ▧ Integrated in framework and libraries
   ▧ Zero additional work
   data class Event(
   …
   val created: Date
   }
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9. @xgouchet
   Type Alias
   ▧ Give context
   ▧ Prevent invalid assignements
   ▧ Ease Maintenance
   typealias Id = Int
   data class Event(
   val id: Id,
   …
   }
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10. @xgouchet
    Type Checking
    ▧ Limit Primitive Scope
    ▧ Validate data
    data class Url(val value: String) {
    init { val parsedUrl = URL(value) }
    }
    data class Event(
    …
    val picture: Url
    }
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11. @xgouchet
    Additional gains
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12. @xgouchet
    Bonus
    ▧ Share common operations
    ▧ Force explicit types
    ▧ Simplify complex structure
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13. @xgouchet
    @xgouchet
    Thanks!
    Any questions?
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