Forbid duplicate test names

[lo1tuma]

No description provided.

[lo1tuma]

The following patterns should be considered a warning

it('foo');
it('foo');

We need to decide if we want to only disallow duplicates in the same describe level or in the whole file.
Should we also disallow duplicate describe names?

[jfmengels]

We need to decide if we want to only disallow duplicates in the same describe level or in the whole file.

In the same describe level.

describe('foo', function() {
  it('should throw when called with null', function() {})
});
describe('bar', function() {
  it('should throw when called with null', function() {})
});

I think it's fine to have the same title here, as the end title would be different for both.

Should we also disallow duplicate describe names?

Yes. Ideally, this should be project wide for top-level describe, but ESLint is not fit to check that.