Thanks for agreeing to review this. This includes:

• A few new constructors for SpherePoint which we don't necessarily need, but which are convenient.
• New Endpoint classes that act as interfaces between the data used by astshim and our specialized classes Point<N>D and SpherePoint.
• The start of a new class Transform which holds two Endpoints and an ast::FrameSet. Only tranForward and tranInverse are supported on this ticket. There are linked tickets to add additional behavior such as returning the Jacobian, making an inverse transform and making a compound transform.

I believe I have addressed all the review issues, including:

• Removing the default constructor for SpherePoint
• Improve the documentation and comments as requested
• Add default copy and move constructors to Endpoint
• Add default move constructors to Transform and disable copy constructors
• Remove one unused import from the Endpoint and Transform pybind11 wrappers

I addition I made the following changes:

• Improved the unit tests as requested.
• Add ostream::operator<< to the C++ classes and __str__ and __repr__ to the Python wrappers. The latter have unit tests. Also the Endpoint version of ostream::operator<< is used by Endpoint.__str__ and __repr__ so it is tested. The Transform version of ostream::operator<< is not used by the Python wrapper (since the templated class name naturally looks different than the C++ class name) and is not tested.
• Fixed a few minor pep8 errors in the new unit tests (my linter was broken when I wrote those tests)

Please have another look.

Also I made each change its own commit (in hopes of making the followup review easier) and separated out work on Endpoint and Transform (to simplify a planned squash). I intend to squash the commits after the review to leave 1 commit each for SpherePoint, Endpoint and Transform.

Thanks for the cleanups. It's unfortunate that we can't use assertFloatsAlmostEqual here, but I guess them's the breaks.

As per John Parejko's request I'm asking Krzysztof Findeisen to have a look at the pybind11 (and anything else of interest).

The pybind11 wrappers look good; I did request some minor changes on GitHub.

Merged. AST is now officially part of the DM stack.