Consolidate testing data modules

[xushiyan]

Make crates/tests the centralized place for providing testing tables. Bind to python using pyo3 and use the testing helpers for python unit tests, and remove the existing testing fixture used in python.

The outcome would be for an IDE (e.g., vscode, rustrover) that imports this project should be able to run all the test suits out-of-the-box without further setup tweaking.

[xushiyan]

@TheR1sing3un are you interested in picking this up? this is some low hanging fruit that we'd like to have so that we can ship faster