An Introduction to Snapshot testing

Transcript

1. AN INTRODUCTION
   
   
   TO SNAPSHOT TESTING
   Freek Van der Herten
   

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2. About me
   
   
   Freek Van der Herten
   
   
   Developer at SPATIE
   
   
   @freekmurze
   
   
   freek.dev
   
   
   spatie.be/products
   
   
   ohdear.app
   

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3. spatie.be/open-source
   
   
   300+ open source packages
   
   
   PHP & Laravel
   
   
   175 million downloads total
   
   
   9 million downloads per month
   

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4. LET’S TALK ABOUT
   

   SNAPSHOT TESTING
   

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5. What?
   
   
   A file on disk – let’s call it a snapshot
   
   
   Test succeeds if the output matches the snapshot
   
   
   If not, the test will fail
   

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6. Where does it come from?
   
   
   Characterisation testing
   
   
   Popularized by Facebook
   
   
   Jest
   
   
   Testing interfaces
   

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7. How can we do it in PHP?
   
   
   github.com/spatie/phpunit-snapshot-assertions
   
   
   github.com/spatie/pest-plugin-snapshots
   
   
   assertMatchesSnapshot
   
   assertMatchesJsonSnapshot
   
   assertMatchesXmlSnapshot
   

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8. DEMO
   

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9. WRAPPING UP
   

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10. Advantages
    
    
    Very easy to get started with
    
    
    Can be used to validate complex output
    
    
    Easily update all the tests in one go
    
    
    

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11. Disadvantages
    
    
    Brittle
    
    
    Hard to pinpoint exact point of failure
    
    
    Bugs can be easily written in the snapshots
    

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12. Interesting links
    
    
    github.com/spatie/phpunit-snapshot-assertions
    
    
    github.com/spatie/pest-plugin-snapshots
    
    
    github.com/spatie/shiki-php
    
    
    github.com/spatie/laravel-markdown
    
    
    torchlight.dev
    

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13. ONE MORE THING
    

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14. testing-laravel.com
    
    
    Premium video course, 6+ hours of video
    
    
    Learn how to tests a Laravel app from scratch
    
    
    Tips and tricks to sharpen your skills
    
    
    Two courses in one: Pest & PHPUnit
    
    
    10 % discount with SPATIE-LOVES-LARACON
    
    
    

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15. Thank you!
    
    
    spatie.be
    
    
    spatie.be/products
    
    
    spatie.be/open-source
    
    
    testing-laravel.com
    
    
    freek.dev
    

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