Add Jest for testing (if there is test folder)

[Sly777]

Add Jest for testing (if there is test folder)

https://facebook.github.io/jest/

Task Rules

• If there is test folder on the root, Jest will run.
• Example pages need to get tests
• All settings should be inside of jest.config.js on root.

[bearcanrun]

I started to tackle this then realized I jumped the gun by adding Jest AND Enzyme. Before I go further in this direction, is using just Jest preferred? Adding Enzyme has a few more twists and is explained in the started documentation Testing.md that you can read in my commit.

[mulyoved]

is using just Jest preferred

I think yes, I prefer using Jest with storyshots and don't use Enzyme

[Sly777]

I think also Jest is enough for most of the scenarios. But if someone says the reason why it's should be, We can discuss. I'm not 100% sure.

[bearcanrun]

We'll just go Jest then! Since getting Enzyme to work wasn't so straight forward, I'll add simple instructions for adding it in the docs.

[Sly777]

perfect! @bearcanrun

[bearcanrun]

So... I've run into a problem. Running Jest in the jsdom test environment throws breaking errors as reported in jsdom #1783. Though it says for ubuntu, I'm on a mac pro and get the same thing. When I change the testEnvironment under Jest config in package.json to 'node', then no problems at all. I realize jsdom is the more ideal testing environment.

First, is anyone willing to check to make sure it's not just me?

git clone -b add-jest --single-branch https://github.com/bearcanrun/ran.git
yarn install && yarn run setup
yarn run jest

If you get error TypeError: Cannot read property '_location' of null then change in package.json:

"jest": {
    ...
    "testEnvironment": "node"
  },

and again run yarn run jest.

Then, any thoughts on course of action? It's weird that I had no problems with Enzyme installed, but it allowed me to easily shallow render the components. With just Jest, you have to mock everything out, at least, for snapshotting pages.

[Sly777]

Hey @bearcanrun, sorry I was not able to check comments on RAN last couple days. Should I test it or did u fix it?

[jaggad]

@bearcanrun Any progress on the jest test integration?