fast-check
hypothesis
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fast-check | hypothesis | |
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21 | 20 | |
4,071 | 7,225 | |
- | 1.2% | |
9.8 | 9.9 | |
4 days ago | 4 days ago | |
TypeScript | Python | |
MIT License | GNU General Public License v3.0 or later |
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For example, an activity of 9.0 indicates that a project is amongst the top 10% of the most actively developed projects that we are tracking.
fast-check
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The 5 principles of Unit Testing
Libraries like JSVerify or Fast-Check offer essential tools to facilitate property-based testing.
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How to Survive Your Project's First 100k Lines
Strong agree!
For JavaScript, I suggest folks check out fast-check [0] and this introduction to property-based testing that uses fast-check [1].
This is broadly useful, but one specific place I've found it helpful was to check redux reducers against generated lists of actions to find unchecked edge cases and data assumptions.
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[AskJS] Should I be generating random data for parameters when unit testing?
There's a library for exactly that: FastCheck.
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Integrate Jest and fast-check together
It makes @fast-check/jest, the best option to integrate Jest and fast-check, as it provides an abstraction over both to ease their mutual integration.
- I Created an API to Generate Mock Information
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Generating dummy entities with random data for tests based on types
The closest that I know of (and I have not used this) is zod-fast-check. It generates fast-check “arbitraries” (test data generators) for property-based testing based on zod schemas. Of course, this requires that you use zod to define your types, which has some downsides. Fortunately there is another tool, ts-to-zod, (which I also have not used) which will codegen zod schemas based on TS type definitions. If you thread these four libraries together you should end up with the ability to write random tests on generated data with very little overhead. In theory.
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In praise of property-based testing (2019)
I've been aware of property-based testing for a number of years now, but never had a good opportunity to give it a try. Then the past year I had a piece of serialisation/de-serialisation code, which was the perfect opportunity for a rather simple property-based test. That gave me the hang of it, and found two (minor, but still) bugs.
Then recently I had a fairly larger, more error prone piece of work that lend itself very well to property-based testing, and it's been a godsend. It helped me discover a number of bugs, this time with the risk of causing privilege escalation. And since the proptests started succeeding reliably, I've been very confident that a rather complex piece of code now actually does what it's supposed to.
If you're working in JavaScript, I can recommend fast-check [1].
Another interesting approach, that I haven't yet tried, is Quickstrom [2], basically Puppeteer for proptests. It opens a webpage in a browser, performs some random interactions (pressing buttons, entering data, etc.), and then verifies that properties you specified still hold.
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Fastcheck: Property based testing for JavaScript and TypeScript
The about says:
Property based testing framework for JavaScript (like QuickCheck) written in TypeScript
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Effective Property-Based Testing
For JS and TypeScript, the best property testing library I've encountered so far is fast-check https://github.com/dubzzz/fast-check
hypothesis
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A Tale of Two Kitchens - Hypermodernizing Your Python Code Base
Hypothesis for Property-Based Testing: Hypothesis is a Python library facilitating property-based testing. It offers a distinct advantage by generating a wide array of input data based on specified properties or invariants within the code. The perks of Hypothesis include:
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Pix2tex: Using a ViT to convert images of equations into LaTeX code
But then add tests! Tests for LaTeX equations that had never been executable as code.
https://github.com/HypothesisWorks/hypothesis :
> Hypothesis is a family of testing libraries which let you write tests parametrized by a source of examples. A Hypothesis implementation then generates simple and comprehensible examples that make your tests fail. This simplifies writing your tests and makes them more powerful at the same time, by letting software automate the boring bits and do them to a higher standard than a human would, freeing you to focus on the higher level test logic.
> This sort of testing is often called "property-based testing", and the most widely known implementation of the concept is the Haskell library QuickCheck, but Hypothesis differs significantly from QuickCheck and is designed to fit idiomatically and easily into existing styles of testing that you are used to, with absolutely no familiarity with Haskell or functional programming needed.
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Python toolkits
Hypothesis to generate dummy data for test.
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Best way to test GraphQL API using Python?
To create your own test cases, I recommend you use hypothesis-graphql in combination with hypothesis. hypothesis is a property-based testing library. Property-based testing is an approach to testing in which you make assertions about the result of a test given certain conditions and parameters. For example, if you have a mutation that requires a boolean parameter, you can assert that the client will receive an error if it sends a different type. hypothesis-graphql is a GraphQL testing library that knows how to use hypothesis strategies to generate query documents.
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Fuzzcheck (a structure-aware Rust fuzzer)
The Hypothesis stateful testing code is somewhat self-contained, since it mostly builds on top of internal APIs that already existed.
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Running C unit tests with pytest
We've had a lot of success combining that approach with property-based testing (https://github.com/HypothesisWorks/hypothesis) for the query engine at backtrace: https://engineering.backtrace.io/2020-03-11-how-hard-is-it-t... .
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Machine Readable Specifications at Scale
Systems I've used for this include https://agda.readthedocs.io/en/v2.6.0.1/getting-started/what... https://coq.inria.fr https://www.idris-lang.org and https://isabelle.in.tum.de
An easier alternative is to try disproving the statement, by executing it on thousands of examples and seeing if any fail. That gives us less confidence than a full proof, but can still be better than traditional "there exists" tests. This is called property checking or property-based testing. Systems I've used for this include https://hypothesis.works https://hackage.haskell.org/package/QuickCheck https://scalacheck.org and https://jsverify.github.io
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Top 5 decentralized app development frameworks
Unlike other frameworks mentioned in this article, Brownie’s test language is Python using hypothesis.
- What Is Property Based Testing?
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Go: Fuzzing Is Beta Ready
People can have different definitions and still communicate usefully, and I think there is not 100% agreement on the exact boundaries between the two.
That said, for me: they are distinct but related, and that distinction is useful.
For example, Hypothesis is a popular property testing framework. The authors have more recently created HypoFuzz, which includes this sentence in the introduction:
“HypoFuzz runs your property-based test suite, using cutting-edge fuzzing techniques and coverage instrumentation to find even the rarest inputs which trigger an error.”
Being able to talk about fuzzing and property testing as distinct things seems useful — saying something like “We added fuzzing techniques to our property testing framework“ is more meaningful than “We added property testing techniques to our property testing framework“ ;-)
My personal hope is there will be more convergence, and work to add first-class fuzzing support in a popular language like Go will hopefully help move the primary use case for fuzzing to be about correctness, with security moving to an important but secondary use case.
What are some alternatives?
pytest - The pytest framework makes it easy to write small tests, yet scales to support complex functional testing
Robot Framework - Generic automation framework for acceptance testing and RPA
Behave - BDD, Python style.
nose2 - The successor to nose, based on unittest2
nose - nose is nicer testing for python
Schemathesis - Automate your API Testing: catch crashes, validate specs, and save time
Unexpected - Unexpected - the extensible BDD assertion toolkit
mamba - The definitive testing tool for Python. Born under the banner of Behavior Driven Development (BDD).
Slash - The Slash testing infrastructure
jest - Delightful JavaScript Testing.
tape - tap-producing test harness for node and browsers
trevor - 🚦 Your own mini Travis CI to run tests locally