Snapy

Webpack based, snapshot only test runner. Currently nodejs only, but with clientside and E2E testing in planning.

Features

• Snapshots only - forces you to do proper tests of input -> output
• Interactively shows you the output and asks about it
• Uses webpack bundles to track changes
• Watches test files and dependencies
• Static analysis of tests to make writing them as easy as possible

Install

npm install --save-dev snapy

Usage

// ./test/test.js// snapy tries to load all files in test directory by default{test}=require("snapy")test((snap)=>{snap({obj: true})})

# in terminal
snapy --help
# usage: snapy <options> (config file)# options:# -w, --watch restart snapy on changes in config# config file is optional and defaults to "snapy.config.[js|json|coffee|ts]"# in "test/" and "/"

snapy.config

Read by read-conf, from ./ or ./test/ by default.

// ./test/snapy.config.jsmodule.exports={// Disable some of the default plugins// $item (String) Package name or filepath (absolute or relative to cwd) of plugindisablePlugins: null,// Array// Snapy plugins to load// type: Array// $item (String) Package name or filepath (absolute or relative to cwd) of pluginplugins: ["snapy-cache","snapy-obj","snapy-entry","snapy-promise","snapy-transform-obj","snapy-filter-obj"],// Will also run tests from unchanged chunksrunAll: false,// Boolean// Environment where the tests are runtarget: "node",// String// Timeout applied on all preparation, test and cleanup callstimeout: 2000,// Number// Level of loggingverbose: 1,// Number// webpack configuration which will be used by mergingwebpack: {},// Object// Path of webpack.config file to use for testingwebpackFile: null,// String// …}

Plugins

You should read the (short) docs of the bold ones.

Activated by default:

• snapy-obj - Take a snapshot of an object
• snapy-promise - Take a snapshot of a promise
• snapy-transform-obj - Transform an object before you take a snapshot
• snapy-filter-obj - Filter properties from a snapshot
• snapy-entry - Sets webpack entry files, when none are given
• snapy-cache - handles the cache writing to disk

Activated by target: "node"

• snapy-node - Test runner for node
• snapy-file - Take a snapshot from a file
• snapy-stream - Take a snapshot of a stream
• snapy-node-report - Asks about the snapshots and offers a error explorer for the terminal

Additional

• snapy-webpack - Take a snapshot of a webpack output

Writing tests

The API is small but powerful:

// ./test/someFile.js{test,prepare,after,getTestId}=require("snapy")// code outside will be called before all tests// prepare(fn)// fn will be called before each test and takes two arguments:// state (optional) a state given by a test// cleanUp(fn) registers a fn which will be called after each test// you can return a value, which will be passed to the testprepare((state,cleanUp)=>{// do somethingcleanUp(=>{// cleanup what you did})// getTestId()// provides you with an unique identifier for current running test// this is important as some tests may run in parallel on different threadsportToUse=8080+getTestId()returnprocessedState})// test(state, fn)// state is optional, and will be passed to prepare call// fn takes two or three arguments// depending if there is a returned value from prepare// snap(obj) will take a snapshot and test it against previous values// processedState: return value of prepare// cleanUp(fn) registers a fn which will be called after this testtest(state,(snap,processedState,cleanUp)=>{snap({obj: true})cleanUp(=>{// cleanup what you did})})// after(fn)// registers a fn which will be called after all testsafter(=>{// more cleanUp})

Caveats

As the tests are statically analysed, you are not allowed to do one of the following:

• don't rename test or snap

{test:tst}=require("snapy")// won't worktest((sn)=>{sn({obj:true})})// won't work

• don't use snap in conditional statements or loops

test((snap)=>{[1,2].forEach((i)=>{snap({obj:i})})// won't work})

• don't define the test outside of the test call

t=(snap)=>{snap({obj:true})}test(t)// won't work

License

Copyright (c) 2018 Paul Pflugradt Licensed under the MIT license.