Nested describes don't run if parent describe has .only (mocha 3)

[jhartikainen]

Previously, if you had a nested describe and tests inside a parent describe with .only, the child-describe blocks would also run.

It seems #1481 may have broken this behavior. While I think the actual fix in 1481 makes sense, this side-effect of it seems counter-intuitive, and at least goes against my expectations of how this should work. It's also different from how this works in some other testing tools I've used in the past with similar features.

Steps to reproduce

1. Create a test file with a root describe using .only.
2. Put another describe inside it, with an it inside
3. Run test

Expected result

The tests inside the nested describe run

Actual result

Only tests immediately inside the parent describe block run, at least with mocha@3.0.0-1

Sample code

describe.only('this should run', function() {
  it('an it should also run', function() { });

  describe('this nested describe should run', function() {
    it('and this nested it should run as well', function() { });
  });
});

Output:

  this should run
    ✓ an it should also run


  1 passing (14ms)

Expected output:

  this should run
    ✓ an it should also run
    this nested describe should run
      ✓ and this nested it should run as well


  2 passing (17ms)

[boneskull]

Yeah, OK, this was clearly the intent of #1807. See this line.

I'll need to re-read the discussion around it, because I wouldn't expect this behavior.

UPDATE: Fixed the PR number twice

[boneskull]

Hmm. Actually I'm not sure this particular case got coverage.

[boneskull]

This is a bit tricky, so I'm not going to finish it tonight; could use some assistance. Basically what needs to happen is if a suite is marked "only", then unless a test within that suite is marked "only", all child suites' tests should run as well. Or, that's what I'd expect, anyhow.

describe.only('foo', function () {
  describe('bar', function () {
    it('should run', function () {});
  });
});

// do we agree?
describe.only('foo', function () {
  it.only('should run', function () {});
  describe('bar', function () {
    it('should not run', function () {});
  });
});

// careful with the order...
describe.only('foo', function () {
  describe('bar', function () {
    it('should not run', function () {});
  });
  it.only('should run', function () {});
});

also deeply-nested suites may complicate matters, as you can't simply check the most immediate parent to see if it has tests marked "only"; when child suites are created, they should be given a false isOnly prop (regardless of whether describe.only() was used!) when the parent has a truthy onlyTests prop OR when the parent has a false isOnly prop. Given that the default value of isOnly is undefined, one could think of this as a ternary flag...

[boneskull]

cc @mochajs/core

this will delay the final v3 release until it's resolved or we can agree that this is what should be happening, which is unlikely...

[boneskull]

@jhartikainen If you're feeling generous, I'd encourage you to pull down the issue/2378 branch and see if the behavior matches what you expect.

[jhartikainen]

@boneskull yep appears to function as expected on that branch

[boneskull]

closed by 9ea2011, but I'm not 100% convinced, so we'll see if this stays closed.