Brian Hicks BrianHicks

Non-Deterministic Testing Overview

Background/motivation: After working through the Unison tour, in particular the section on testing, I feel a little weird about caching property test results. I raised this on the Unison Slack, and we decided that it would be helpful for me to write up an overview of non-deterministic testing as a way to contribute. So, here goes!

Non-deterministic tests generally fall into two categories:

property tests, where random values are fed into a function to assure a property holds (e.g. to assert that a function is idempotent by checking fn a == fn (fn a).) Examples: QuickCheck (Haskell/Erlang), Hedgehog (Haskell/F#/C#/R/Scala), Hypothesis (Python), elm-test (Elm)
fuzz tests, where a random bytes are given to a program to make sure it behaves properly in the face of malformed input. These tests usually start with a corpus of inputs and mutate them using a genetic algorithm guided by co

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	[package]
	name = "montage"
	version = "0.1.0"
	edition = "2021"

	# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html

	[dependencies]
	async-graphql = { version = "5.0.10", features = ["chrono", "chrono-duration", "chrono-tz", "tokio", "tracing"] }
	async-graphql-warp = "5.0.10"

	#!/usr/bin/env python3
	"""
	Build an Elm app, but isolate the working directory so that multiple Elm
	compiler invocations can run in parallel without corrupting `.elmi` files.
	"""
	from argparse import ArgumentParser, ArgumentTypeError
	import json
	import logging
	import os
	import os.path

	Deployment Controller
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	push event -> Building Push Events
	reserve -> Reserved

	Building Push Events
	Building Only Item
	finish build -> Waiting for Push Event
	cancel build -> Waiting for Push Event

	Guided Draft
	Example Closed
	Never Saw Example
	open example -> Example Opening
	Saw Example
	open example -> Example Open At Previous Scroll Position
	Example Opening
	finish scrolling animation -> Example Open At Previous Scroll Position
	Example Open At Previous Scroll Position
	close example -> Saw Example

	Comment
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	{
	"id": "custom-833cffe0-8447-4941-b97e-bdd4870bdeef",
	"name": "QGMLWY",
	"version": 1,
	"keys": {
	"KeyQ": {
	"default": {
	"base": "q",
	"shift": "Q"
	}

	module Slice exposing
	( Slice, slice
	, Multiple, Position(..), before, after, getList
	, Single, first, last, get, map
	)

	{-\| Bisect a `Todos` in whatever way.


	# initializing a slice