rspecs.md

April 22, 2017

Recreating RSpec

Idea from WAT guy

describe MeetupUser do
...
end 

Could also have a string - if you want a bunch of tests for a concept.

describe "hi there" do
...
end 

Lazy vs. Eager

Pupr

let(name){value} #lazy
let!(:name2){value2} #eager

• lazy: makes it when you want it
• eager: runs it first

The order in which Ruby parases it.

• Only when it sees

expect(name2).to eq("Harry")

eq("Harry") is the predicate

Generally

• Want to use let(:name)
• Runs once
• Caches name2

Two reasons:

• Want to do some setup before defining
• Performance issues

let!

Need some thing to exist in the database for some side-effect.

Example: There are disaster zones in Airbnb. Would want to call with let! because then need to see effects in the database.

Before

• Good for setup, i.e.Redis.set key
• Good for something that you only need a side effect for
• BUT if you need a reference to something you've created before -Then you would want to use let! so you can keep a reference to it

Subject

• Another way to have let

subject(:hero) { Hero.first }

Allow

Example: never in Rails.env.production?

allow(Rails.env).to receive(:production?).and_return(true)

Stubbing

Stubbing: " programs that simulate the behaviors of software components (or modules) that a module undergoing tests depends on"

Example: VCR, gem that makes external API calls, saves response. Now deterministic. Hits Github API - saves response.

Service Oriented Architecture

• Everything you're talking to is an API
• For every single service, you're talking to - have to stub out the response.

Chron Job

Runs a test at a scheduled time.

• Heroku equivalent: Heroku Scheduler In production: When you're working on a codebase, set up chron jobs to monitor performance.

Might also want to stub external classes

• Unit tests: test one particular component, testing a SINGLE component

• Integration tests: test components as integrated, "end-to-end testing" "Stub out all of the dependencies"

• Not testing external dependencies, testing sending out correct methods

• Controller specs

Everything that happens in your app, should go through your controller

• Cannot have expect without stubbing*

Overwrite method

• RSpecs is doing this for us under the hood

Core Features

• Nested describe, before, let blocks
• Expect

Thanks to Hafseb