Stephen Boyd stephenboyd

Idiomatic React Testing Patterns

Testing React components seems simple at first. Then you need to test something that isn't a pure interaction and things seem to break down. These 4 patterns should help you write readable, flexible tests for the type of component you are testing.

Setup

I recommend doing all setup in the most functional way possible. If you can avoid it, don't set variables in a beforeEach. This will help ensure tests are isolated and make things a bit easier to reason about. I use a pattern that gives great defaults for each test example but allows every example to override props when needed:

In this gist I would like to describe an idea for GraphQL subscriptions. It was inspired by conversations about subscriptions in the GraphQL slack channel and different GH issues, like #89 and #411.

Conceptual Model

At the moment GraphQL allows 2 types of queries:

query
mutation

Reference implementation also adds the third type: subscription. It does not have any semantics yet, so here I would like to propose one possible semantics interpretation and the reasoning behind it.

Deploying a Meteor app to Digital Ocean

	console.log(1);
	(_ => console.log(2))();
	eval('console.log(3);');
	console.log.call(null, 4);
	console.log.apply(null, [5]);
	new Function('console.log(6)')();
	Reflect.apply(console.log, null, [7])
	Reflect.construct(function(){console.log(8)}, []);
	Function.prototype.apply.call(console.log, null, [9]);
	Function.prototype.call.call(console.log, null, 10);

	package main

	import (
	"context"
	"crypto/tls"
	"fmt"
	"log"
	"net/http"
	"net/url"
	"time"

	import { h, cloneElement, Component } from 'preact';


	/** Example <Fetch url="/foo.json" /> compositional component.
	* Just to demonstrate a compositional component that requires input massaging.
	*/
	class Fetch extends Component {
	state = { loading: true };
	componentDidMount() {
	this.update();

	let isFunction = function(obj) {
	return typeof obj == 'function' \|\| false;
	};

	class EventEmitter {
	constructor() {
	this.listeners = new Map();
	}
	addListener(label, callback) {
	this.listeners.has(label) \|\| this.listeners.set(label, []);

	import React from 'react';
	import Flickity from 'flickity';

	export default React.createClass({

	getInitialState() {
	return {
	selectedIndex: 0
	}
	},

	// Usage:
	// Copy and paste all of this into a debug console window of the "Who is Hiring?" comment thread
	// then use as follows:
	//
	// query(term \| [term, term, ...], term \| [term, term, ...], ...)
	//
	// When arguments are in an array then that means an "or" and when they are seperate that means "and"
	//
	// Term is of the format:
	// ((-)text/RegExp) ( '-' means negation )

	Template.categorySelected.onCreated(function () {

	var instance = this;

	instance.autorun(function () {
	instance.subscribe('packages', Router.current().params.category_slug)
	});

	instance.packages = function () {
	return Packages.find({}, {sort: {"GitHub.subscribers_count": -1, "GitHub.stargazers_count": -1}})

Stephen Boyd stephenboyd

Idiomatic React Testing Patterns

Setup

Conceptual Model

Deploying a Meteor app to Digital Ocean

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