RFC: Test runner integration

[krzkaczor]

Test runner integration (beforeEach/afterEach) /should be implemented to avoid repetition and hard to spot bugs. I propose to not worry about parallel test execution at this stage.

What should happen during integration?

Autoload all earl plugins (with external matchers).

After each test:

• automatically verify all created strictMocks (RFC: Function Mocks #12)

Before each test:

• set context for earl like earl.setContext({name: "testSuite/testName"}) That would allow implementation of snapshots without a need to provide a name for it (same interface as jest). I don't want to dive into this now since I am not sure if we want to implement snapshots at all 🤔

How integration should look like

Perfectly it would be as simple as -r earl/integrate-mocha but I am not sure if this can be done like this or we need to force users to add somewhere in there test suite snippet like:

beforeEach(earl.beforeEach)
afterEach(earl.afterEach)

I think earl should ship with integrations for most popular test runners (at least for mocha).

[krzkaczor]

I did a quick prototype. As I was suspecting, during require phase mocha is not yet fully initialized but you can just wait till it is :-> This works: (I am not sure if it's reliable)

async function main() {
  // sync setup like discovering and loading plugins

  // we need to delay execution after mocha finishes initialization
  await Promise.resolve()

  beforeEach(function(){
    console.log("Setting earl!")
    console.log(this.currentTest)
  })
}

main()

and it's super easy to configure with .mocharc.js just by placing:

module.exports = {
  require: ["earl/mocha"],
  // ...
};

[krzkaczor]

Mocha's team works on "Root Hook Plugins", this would allow earl to work in parallel mode in mocha:

mochajs/mocha#4244

[krzkaczor]

Basic implementation was just merged. I realized that it needs a little bit more work to properly support mocks created outside of "it" block.