Jest/Mocha not picking up all tests

[maximilianschmitt]

Hi!

We're looking to parallelize our mocha-based test suite and we think that going with jest and jest-runner-mocha might be the easiest way to get there.

There is one problem we're running into and that is that Jest/Mocha are not picking up all the tests and so quite a few fail with Your test suite must contain at least one test..

The following types of tests are not being picked up:

1. Tests written with co-mocha in mind

Example (notice the generator function):

it('registers a user', function*() {
  const user = yield createUser()
  expect(yield findUser(user.id)).toEqual(true)
})

We've tried require('co-mocha')(require('mocha')) from our jest config file and also from within jest-runner-mocha but that didn't get us anywhere.

2. Tests that generate the it call dynamically

Example:

testForValidationError("when input is invalid", function() {
  return runRequest(invalidInput)
})

function testForValidationError(description, fn) {
  it(`rejects with validation error ${description}`, function() {
    return fn().then(assertValidationError)
  })
}

What can we do to have Jest/Mocha pick up those tests?

Thanks for your help!

[rogeliog]

Thanks for reporting!

• It is finding the files right?
• Does it work when you run it with Mocha(without Jest)
• Are you using any mocha options?

[maximilianschmitt]

Hi @rogeliog, thanks for getting back to me!

• Yes, it's finding the files. Just not the individual tests (its) written in the way described in the OP
• Yes, these tests have been running with Mocha correctly
• No, I'm not using any Mocha options

Using mocha@4.0.1 by the way.

Any ideas?

[ljharb]

I would very much expect the generator example to fail, since that's a pretty weird hack around mocha, which doesn't have generator support (n.b: generators aren't and can't be coroutines, and combining them with a runner is just faking it)

However, I would also very much expect the dynamic it example to work identically, since that's just moving synchronous code around.

[maximilianschmitt]

I'm sorry, the issue was something completely different:

If a promise is rejected (or an error is thrown) inside a beforeEach or if timeout is exceeded in a beforeEach, you will see Your test suite must contain at least one test. but the actual error will not be reported. I think I should create a separate issue for that?

@ljharb generators did turn out to be working as coroutines with co-mocha, as did the dynamic its, like they should :) thanks!