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Maxi Contieri
Maxi Contieri

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Code Smell 91 - Test Asserts without Description

We are big fans of xUnit. But we don't care much for the programmers.

TL;DR: Use asserts with declarative descriptions.

Problems

  • Readability

  • Hard debugging

  • Time waste

Solutions

  1. Put a nice descriptive assertion

  2. Share guides for problem-solving

Sample Code

Wrong

<?

public function testNoNewStarsAppeared(): void
  {
     $expectedStars = $this->historicStarsOnFrame();
     $observedStars = $this->starsFromObservation();
     //These sentences get a very large collection

     $this->assertEquals($expectedStars, $observedStars);
     //If something fails we will have a very hard debugging time
    }
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Right

<?

public function testNoNewStarsAppeared(): void
  {
     $expectedStars = $this->historicStarsOnFrame();
     $observedStars = $this->starsFromObservation();
     //These sentences get a very large collection

     $newStars = array_diff($expectedStars, $observedStars);

     $this->assertEquals($expectedStars, $observedStars ,
         'There are new stars ' . print_r($newStars,true));
     //Now we can see EXACTLY why the assertion failed with a clear and
     //Declarative Message 
    }
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Detection

Since assert and assertDescription are different functions, we can adjust our policies to favour the latter.

Tags

  • Test Smells

Conclusion

Be respectful to the reader of your assertions.

It might even be yourself!

More Info

Credits

Photo by Startaê Team on Unsplash


Always code as if the guy who ends up maintaining your code will be a violent psychopath who knows where you live.

John Woods


This article is part of the CodeSmell Series.

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