Since dataflow, points-to, call-graph and type-inference are all interlinked it makes sense to test them together.
The test code is all under the code/ subdirectory and all test files are named \w_name, supporting
files do have an underscore as their second character.
This allows tests to be applied to a subset of the test data and test/data combinations to be turned on/off easily for debugging.
Be aware that here are two __init__.py, so the results are interleaved.