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https://github.com/Wilfred/propcheck
Quickcheck/hypothesis style testing for elisp
https://github.com/Wilfred/propcheck
emacs-lisp hypothesis-testing quickcheck
Last synced: 3 months ago
JSON representation
Quickcheck/hypothesis style testing for elisp
- Host: GitHub
- URL: https://github.com/Wilfred/propcheck
- Owner: Wilfred
- Created: 2018-10-15T00:02:22.000Z (over 5 years ago)
- Default Branch: master
- Last Pushed: 2021-03-01T01:43:34.000Z (over 3 years ago)
- Last Synced: 2024-01-21T21:50:05.654Z (6 months ago)
- Topics: emacs-lisp, hypothesis-testing, quickcheck
- Language: Emacs Lisp
- Homepage:
- Size: 106 KB
- Stars: 59
- Watchers: 4
- Forks: 1
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
Lists
- awesome - propcheck - Quickcheck/hypothesis style testing for elisp (Emacs Lisp)
- awesome-stars - Wilfred/propcheck - Quickcheck/hypothesis style testing for elisp (Emacs Lisp)
README
# propcheck [](https://coveralls.io/github/Wilfred/propcheck?branch=master)
propcheck brings property based testing to elisp.
It's similar to the excellent [Hypothesis](https://hypothesis.works/)
library for Python.
Status: beta. It works, but expect rough edges.
## Usage
Tests are defined with `propcheck-deftest`, which defines an ERT test
just like `ert-deftest`.
Your test should generate input values with the propcheck generator
functions, then call `propcheck-should` to make assertions about the
result.
```emacs-lisp
(require 'propcheck)
(defun buggy-zerop (num)
;; Return t for all values >= 0. This is wrong! We'll claim that 42
;; is zero.
;;
;; There are lots of numbers that produce a wrong result from this
;; function, but 1 is the smallest. Ideally propcheck would report 1
;; as failing example. It usually does.
(>= num 0))
(propcheck-deftest buggy-zerop-should-match-zerop ()
;; The body of this test will be evaluated repeatedly (up to
;; `propcheck-max-examples` times). The value generated will be
;; different on each iteration.
;;
;; If the assertion ever fails, propcheck will call the body again
;; with progressively smaller values, then report the smallest
;; failing example it could find.
(let* ((i (propcheck-generate-integer "i")))
(propcheck-should
(eq (zerop i)
(buggy-zerop i)))))
```
## Generators
propcheck provides the following generators:
* `propcheck-generate-bool`
* `propcheck-generate-integer`
* `propcheck-generate-float`
* `propcheck-generate-ascii-char`
* `propcheck-generate-proper-list`
* `propcheck-generate-vector`
* `propcheck-generate-string`
* `propcheck-generate-one-of`
### Using Generators Interactively
Generally you'll want to use `propcheck-deftest` to handle seeds for
you. You can still experiement with generator functions in `M-x ielm`
if you bind `propcheck-seed` first. Here's an example:
``` emacs-lisp
(let ((propcheck-seed (propcheck-seed)))
(propcheck-generate-string nil)) ; e.g. "M26gM{^*v "
```