Add some content of optional_dependencies to traits.testing.api

[kitchoi]

Pyface needed requires_numpy and numpy from traits.testing.optional_dependencies (see discussion). So this issue is for moving these objects (maybe along others too) to traits.testing.api so that pyface can import from it safely (related to #1213)

[mdickinson]

I'd rather have Pyface re-implement than import from Traits here. The functionality has nothing particularly to do with Traits, and Traits is not the right place for common non-Trait-related utilities.

[rahulporuri]

i think it's still useful to make optional_dependencies accessible from the api module.

[kitchoi]

For the record, I am in favour of pyface reimplementing those objects.

[mdickinson]

i think it's still useful to make optional_dependencies accessible from the api module.

I disagree. Everything we put in an api module is something we're guaranteeing to support. Traits already has a bunch of utilities that have nothing to do with Traits in particular; I don't want to add to those.

Utilities that are directly Traits-related are a different matter, of course.

[kitchoi]

I am happy for this issue to be closed as a wont-fix...

[kitchoi]

Closing... If anyone wants to advocate further for this, please feel free to reopen.