sympy/sympy — pull request #641 by mattpap (2011-10-09 07:36:27+00:00)
Title: Test whether elements of args are instances of Basic

1. Added tests for all subclasses of `Basic`.
2. Fixed `Limit` (`dir` is now an instance of `Symbol`).
3. There are a few classes to be fixed (see XFAILed tests).
4. All tests related to `sympy.physics` are SKIPed (arguments have to be added to constructors).