The tasty-lens package

[ Tags: bsd3, lenses, library, testing ] [ Propose Tags ]

Preassembled tasty TestTrees for property testing Lenses, Setters, Traversals, Isos and Prisms laws.

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Versions 0.3, 0.3.1
Change log
Dependencies base (>=4.6 && <4.9), lens (>=, smallcheck (>=1.1.1), smallcheck-lens (>=0.3), tagged (>=0.7.2), tasty (>=0.10), tasty-smallcheck (>= [details]
License BSD3
Author Danny Navarro
Category Testing, Lenses
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Source repo head: git clone git://
Uploaded Wed Sep 23 10:55:35 UTC 2015 by jdnavarro
Distributions NixOS:0.3.1
Downloads 457 total (10 in the last 30 days)
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Status Docs available [build log]
Last success reported on 2015-09-23 [all 1 reports]
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Maintainer's Corner

For package maintainers and hackage trustees

Readme for tasty-lens-0.3.1

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Tasty Lens

Hackage Version Build Status

Preassembled tasty TestTrees with sensible defaults for the validation of:

  • Lens
  • Setter
  • Traversal
  • Iso
  • Prism

Although these tests offer weaker guarantees compared to manually proving the laws through equational reasoning, they can still be useful for regression testing where you don't want to manually proof every time you make a slight change that could affect the laws.

It uses smallcheck-lens under the hood. If you don't find any functions to create the TestTrees you are looking for, you may want to use the smallcheck-lens package directly. In such case you can still check this package as a reference to implement your own smallcheck-lens TestTrees.

Check the tests in this package for usage examples.


Contributions and bug reports are welcome!

Please feel free to contact jdnavarro on the #haskell IRC channel on