Integration Tests with Super Powers And even more... Alexandre - - PowerPoint PPT Presentation

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Integration Tests with Super Powers And even more... Alexandre - - PowerPoint PPT Presentation

May 14, 2023 116 likes •350 views

Integration Tests with Super Powers And even more... Alexandre Figura Site Reliability Engineer @ SysEleven GmbH A Brillant Masterpiece Irresistibly Entertaining The Python Magazine Edinburgh Times

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Integration Tests
 with Super Powers

And even more...

Alexandre Figura · Site Reliability Engineer @ SysEleven GmbH

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A Brillant Masterpiece Golden Snake Awards

Nominated for

Best Speaker

Alexandre Figura

⭐⭐⭐⭐⭐ The Most Exciting Talk of the Year ⭐⭐⭐⭐⭐ ⭐⭐⭐⭐⭐

The Python Magazine Scottish Insiders

Irresistibly Entertaining ⭐⭐⭐⭐⭐

Edinburgh Times

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Who Am I?

3

  • Use Python with 😎 since 2014.
  •  Live in Berlin 🛬 since 2016 
  • Always eat 2 desserts at lunch 🍧
  • Work with cool folks at SysEleven GmbH,


best company in town.

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Tests and
 Programmers

❤ A True Love Story ❤

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A Well-Kept Secret

There is one And only one Reason why we write tests. We want our Pull-Requests to get accepted. And incidentally, to make it easier to maintain our code in the future.

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Lazy Mocking

Or how harmful mocks can be...

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Mocks

Advantages

  • Easy to write.

Drawbacks

  • Dependant on implementation,
  • Make refactoring harder,
  • Hide errors and behavioral changes.

Conclusion Never use them*

*Unless you have a very good reason...

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Please Do Not Try Mocks at Home

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Alternative Testing Strategies

...Pimp my Mock™...

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Basic Concepts

Integration Tests are built around two ideas:

  • 1. Dependency Injection,
  • 2. Interface Testing.

It sounds complicated. But it isn't.

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Summary

Advantages:

  • Tests not dependant anymore on implementation.
  • Easy to change dependency later on.
  • Make refactoring easier.

Drawbacks:

  • Require way more work at first.
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Real World Example

When practice meets theory...

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To the Cloud and Beyond

Use Case We want to upload a static website To the Cloud Using OpenStack Object Store's API. Links:

  • Officiel API, - Fake Implementation,
  • Interface Tests,
  • Parametrizing with Pytest.

Container Object Object Object Object Object Store

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Additional Examples


  • f

Dependency Injection

Let's eat the snake!

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Mock Injection

Too much work to write Fake dependencies?

  • Write a Mock-like implementation,
  • Inject it as a dependency.

Useful for simulating complex systems. Advantages:

  • Easy as mocks,
  • Tests remaining independent of implementation


(makes refactoring easier).

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Minimalist Interface Testing

Use Case: I make Holiday movies Recorded on Blu-ray And need to convert them to MKV. Problem: A Blu-Ray is 30-50GB large. Solution: Only check for syntax errors. Links:

  • Syntax Errors Testing,
  • Fake Implementations,
  • Dependency Injection.
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💹 Bonus 💹 Running inside Docker Compose

Because Buzzwords matter...

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Standard Workflow

Tests independent

  • f running platform.

Working example available on Github. Docker Compose Application Container Container 2 Container 3 Source Code Tox +
 Pytest Container 4

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Conclusion

What you should remember

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Summary

Mocks make refactoring harder. Interface Testing is more flexible, but involves more work. Dependency Injection will improve your code's API. Always ask yourself (or around)
 if you need 100% test coverage.

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Everything is about Tradeoffs

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We're hiring! Interested? 
 Just say: "Hello!"

Mail: jobs@syseleven.de WhatsApp, SMS: +49 171/8934073